Cell membrane glycoproteins that are selectively permeable to potassium ions. At least eight major groups of K channels exist and they are made up of dozens of different subunits.
An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
Potassium channels where the flow of K+ ions into the cell is greater than the outward flow.
A class of drugs that act by inhibition of potassium efflux through cell membranes. Blockade of potassium channels prolongs the duration of ACTION POTENTIALS. They are used as ANTI-ARRHYTHMIA AGENTS and VASODILATOR AGENTS.
Potassium channel whose permeability to ions is extremely sensitive to the transmembrane potential difference. The opening of these channels is induced by the membrane depolarization of the ACTION POTENTIAL.
Gated, ion-selective glycoproteins that traverse membranes. The stimulus for ION CHANNEL GATING can be due to a variety of stimuli such as LIGANDS, a TRANSMEMBRANE POTENTIAL DIFFERENCE, mechanical deformation or through INTRACELLULAR SIGNALING PEPTIDES AND PROTEINS.
Voltage-gated potassium channels whose primary subunits contain six transmembrane segments and form tetramers to create a pore with a voltage sensor. They are related to their founding member, shaker protein, Drosophila.
A delayed rectifier subtype of shaker potassium channels that is the predominant VOLTAGE-GATED POTASSIUM CHANNEL of T-LYMPHOCYTES.
A delayed rectifier subtype of shaker potassium channels that is selectively inhibited by a variety of SCORPION VENOMS.
The opening and closing of ion channels due to a stimulus. The stimulus can be a change in membrane potential (voltage-gated), drugs or chemical transmitters (ligand-gated), or a mechanical deformation. Gating is thought to involve conformational changes of the ion channel which alters selective permeability.
A delayed rectifier subtype of shaker potassium channels that is commonly mutated in human episodic ATAXIA and MYOKYMIA.
Potassium channels whose activation is dependent on intracellular calcium concentrations.
Voltage-dependent cell membrane glycoproteins selectively permeable to calcium ions. They are categorized as L-, T-, N-, P-, Q-, and R-types based on the activation and inactivation kinetics, ion specificity, and sensitivity to drugs and toxins. The L- and T-types are present throughout the cardiovascular and central nervous systems and the N-, P-, Q-, & R-types are located in neuronal tissue.
A family of voltage-gated potassium channels that are characterized by long N-terminal and C-terminal intracellular tails. They are named from the Drosophila protein whose mutation causes abnormal leg shaking under ether anesthesia. Their activation kinetics are dependent on extracellular MAGNESIUM and PROTON concentration.
A shaker subfamily that is prominently expressed in NEURONS and are necessary for high-frequency, repetitive firing of ACTION POTENTIALS.
A voltage-gated potassium channel that is expressed primarily in the HEART.
A family of delayed rectifier voltage-gated potassium channels that share homology with their founding member, KCNQ1 PROTEIN. KCNQ potassium channels have been implicated in a variety of diseases including LONG QT SYNDROME; DEAFNESS; and EPILEPSY.
A delayed rectifier subtype of shaker potassium channels that conducts a delayed rectifier current. It contributes to ACTION POTENTIAL repolarization of MYOCYTES in HEART ATRIA.
A fast inactivating subtype of shaker potassium channels that contains two inactivation domains at its N terminus.
A subfamily of shaker potassium channels that shares homology with its founding member, Shab protein, Drosophila. They regulate delayed rectifier currents in the NERVOUS SYSTEM of DROSOPHILA and in the SKELETAL MUSCLE and HEART of VERTEBRATES.
A major class of calcium activated potassium channels whose members are voltage-dependent. MaxiK channels are activated by either membrane depolarization or an increase in intracellular Ca(2+). They are key regulators of calcium and electrical signaling in a variety of tissues.
Heteromultimers of Kir6 channels (the pore portion) and sulfonylurea receptor (the regulatory portion) which affect function of the HEART; PANCREATIC BETA CELLS; and KIDNEY COLLECTING DUCTS. KATP channel blockers include GLIBENCLAMIDE and mitiglinide whereas openers include CROMAKALIM and minoxidil sulfate.
A very slow opening and closing voltage-gated potassium channel that is expressed in NEURONS and is commonly mutated in BENIGN FAMILIAL NEONATAL CONVULSIONS.
Potassium channels that contain two pores in tandem. They are responsible for baseline or leak currents and may be the most numerous of all K channels.
A very slow opening and closing voltage-gated potassium channel that is expressed in NEURONS and is closely related to KCNQ2 POTASSIUM CHANNEL. It is commonly mutated in BENIGN FAMILIAL NEONATAL CONVULSIONS.
A shaker subfamily of potassium channels that participate in transient outward potassium currents by activating at subthreshold MEMBRANE POTENTIALS, inactivating rapidly, and recovering from inactivation quickly.
The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).
A class of drugs that act by selective inhibition of calcium influx through cellular membranes.
A family of inwardly-rectifying potassium channels that are activated by PERTUSSIS TOXIN sensitive G-PROTEIN-COUPLED RECEPTORS. GIRK potassium channels are primarily activated by the complex of GTP-BINDING PROTEIN BETA SUBUNITS and GTP-BINDING PROTEIN GAMMA SUBUNITS.
A major class of calcium-activated potassium channels that are found primarily in excitable CELLS. They play important roles in the transmission of ACTION POTENTIALS and generate a long-lasting hyperpolarization known as the slow afterhyperpolarization.
The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.
An electrophysiologic technique for studying cells, cell membranes, and occasionally isolated organelles. All patch-clamp methods rely on a very high-resistance seal between a micropipette and a membrane; the seal is usually attained by gentle suction. The four most common variants include on-cell patch, inside-out patch, outside-out patch, and whole-cell clamp. Patch-clamp methods are commonly used to voltage clamp, that is control the voltage across the membrane and measure current flow, but current-clamp methods, in which the current is controlled and the voltage is measured, are also used.
A group of slow opening and closing voltage-gated potassium channels. Because of their delayed activation kinetics they play an important role in controlling ACTION POTENTIAL duration.
Cell membrane glycoproteins that form channels to selectively pass chloride ions. Nonselective blockers include FENAMATES; ETHACRYNIC ACID; and TAMOXIFEN.
An antidiabetic sulfonylurea derivative with actions similar to those of chlorpropamide.
A potassium-selective ion channel blocker. (From J Gen Phys 1994;104(1):173-90)
The ability of a substrate to allow the passage of ELECTRONS.
Female germ cells derived from OOGONIA and termed OOCYTES when they enter MEIOSIS. The primary oocytes begin meiosis but are arrested at the diplotene state until OVULATION at PUBERTY to give rise to haploid secondary oocytes or ova (OVUM).
The commonest and widest ranging species of the clawed "frog" (Xenopus) in Africa. This species is used extensively in research. There is now a significant population in California derived from escaped laboratory animals.
Long-lasting voltage-gated CALCIUM CHANNELS found in both excitable and nonexcitable tissue. They are responsible for normal myocardial and vascular smooth muscle contractility. Five subunits (alpha-1, alpha-2, beta, gamma, and delta) make up the L-type channel. The alpha-1 subunit is the binding site for calcium-based antagonists. Dihydropyridine-based calcium antagonists are used as markers for these binding sites.
A major class of calcium-activated potassium channels that were originally discovered in ERYTHROCYTES. They are found primarily in non-excitable CELLS and set up electrical gradients for PASSIVE ION TRANSPORT.
An aquatic genus of the family, Pipidae, occurring in Africa and distinguished by having black horny claws on three inner hind toes.
One of the POTASSIUM CHANNEL BLOCKERS, with secondary effect on calcium currents, which is used mainly as a research tool and to characterize channel subtypes.
The pore-forming subunits of large-conductance calcium-activated potassium channels. They form tetramers in CELL MEMBRANES.
Venoms from animals of the order Scorpionida of the class Arachnida. They contain neuro- and hemotoxins, enzymes, and various other factors that may release acetylcholine and catecholamines from nerve endings. Of the several protein toxins that have been characterized, most are immunogenic.
A potassium-channel opening vasodilator that has been investigated in the management of hypertension. It has also been tried in patients with asthma. (Martindale, The Extra Pharmacopoeia, 30th ed, p352)
A guanidine that opens POTASSIUM CHANNELS producing direct peripheral vasodilatation of the ARTERIOLES. It reduces BLOOD PRESSURE and peripheral resistance and produces fluid retention. (Martindale The Extra Pharmacopoeia, 31st ed)
A 37-amino acid residue peptide isolated from the scorpion Leiurus quinquestriatus hebraeus. It is a neurotoxin that inhibits calcium activated potassium channels.
Potassium or potassium compounds used in foods or as foods.
A class of drugs that act by inhibition of sodium influx through cell membranes. Blockade of sodium channels slows the rate and amplitude of initial rapid depolarization, reduces cell excitability, and reduces conduction velocity.
ATP-BINDING CASSETTE PROTEINS that are highly conserved and widely expressed in nature. They form an integral part of the ATP-sensitive potassium channel complex which has two intracellular nucleotide folds that bind to sulfonylureas and their analogs.
A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.
Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
An element of the alkaline earth group of metals. It has an atomic symbol Ba, atomic number 56, and atomic weight 138. All of its acid-soluble salts are poisonous.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
CALCIUM CHANNELS that are concentrated in neural tissue. Omega toxins inhibit the actions of these channels by altering their voltage dependence.
An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.
Inorganic compounds that contain barium as an integral part of the molecule.
A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.
A condition due to decreased dietary intake of potassium, as in starvation or failure to administer in intravenous solutions, or to gastrointestinal loss in diarrhea, chronic laxative abuse, vomiting, gastric suction, or bowel diversion. Severe potassium deficiency may produce muscular weakness and lead to paralysis and respiratory failure. Muscular malfunction may result in hypoventilation, paralytic ileus, hypotension, muscle twitches, tetany, and rhabomyolysis. Nephropathy from potassium deficit impairs the concentrating mechanism, producing POLYURIA and decreased maximal urinary concentrating ability with secondary POLYDIPSIA. (Merck Manual, 16th ed)
The rate dynamics in chemical or physical systems.
Inorganic compounds that contain potassium as an integral part of the molecule.
A subgroup of TRP cation channels that contain 3-4 ANKYRIN REPEAT DOMAINS and a conserved C-terminal domain. Members are highly expressed in the CENTRAL NERVOUS SYSTEM. Selectivity for calcium over sodium ranges from 0.5 to 10.
A subgroup of cyclic nucleotide-regulated ION CHANNELS within the superfamily of pore-loop cation channels. They are expressed in OLFACTORY NERVE cilia and in PHOTORECEPTOR CELLS and some PLANTS.
A heterogenous group of transient or low voltage activated type CALCIUM CHANNELS. They are found in cardiac myocyte membranes, the sinoatrial node, Purkinje cells of the heart and the central nervous system.
The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.
Compounds with a core of fused benzo-pyran rings.
A highly neurotoxic polypeptide from the venom of the honey bee (Apis mellifera). It consists of 18 amino acids with two disulfide bridges and causes hyperexcitability resulting in convulsions and respiratory paralysis.
The regulatory subunits of large-conductance calcium-activated potassium channels.
The relationship between the dose of an administered drug and the response of the organism to the drug.
Agents that increase calcium influx into calcium channels of excitable tissues. This causes vasoconstriction in VASCULAR SMOOTH MUSCLE and/or CARDIAC MUSCLE cells as well as stimulation of insulin release from pancreatic islets. Therefore, tissue-selective calcium agonists have the potential to combat cardiac failure and endocrinological disorders. They have been used primarily in experimental studies in cell and tissue culture.
Proteins that bind specific drugs with high affinity and trigger intracellular changes influencing the behavior of cells. Drug receptors are generally thought to be receptors for some endogenous substance not otherwise specified.
The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.
A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.
A derivative of the NIACINAMIDE that is structurally combined with an organic nitrate. It is a potassium-channel opener that causes vasodilatation of arterioles and large coronary arteries. Its nitrate-like properties produce venous vasodilation through stimulation of guanylate cyclase.
A member of the alkali metals. It has an atomic symbol Cs, atomic number 50, and atomic weight 132.91. Cesium has many industrial applications, including the construction of atomic clocks based on its atomic vibrational frequency.
A white crystal or crystalline powder used in BUFFERS; FERTILIZERS; and EXPLOSIVES. It can be used to replenish ELECTROLYTES and restore WATER-ELECTROLYTE BALANCE in treating HYPOKALEMIA.
Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.
The movement of ions across energy-transducing cell membranes. Transport can be active, passive or facilitated. Ions may travel by themselves (uniport), or as a group of two or more ions in the same (symport) or opposite (antiport) directions.
A family of proton-gated sodium channels that are primarily expressed in neuronal tissue. They are AMILORIDE-sensitive and are implicated in the signaling of a variety of neurological stimuli, most notably that of pain in response to acidic conditions.
Sodium channels found on salt-reabsorbing EPITHELIAL CELLS that line the distal NEPHRON; the distal COLON; SALIVARY DUCTS; SWEAT GLANDS; and the LUNG. They are AMILORIDE-sensitive and play a critical role in the control of sodium balance, BLOOD VOLUME, and BLOOD PRESSURE.
A benzothiadiazine derivative that is a peripheral vasodilator used for hypertensive emergencies. It lacks diuretic effect, apparently because it lacks a sulfonamide group.
Single chains of amino acids that are the units of multimeric PROTEINS. Multimeric proteins can be composed of identical or non-identical subunits. One or more monomeric subunits may compose a protomer which itself is a subunit structure of a larger assembly.
Venoms from snakes of the family Elapidae, including cobras, kraits, mambas, coral, tiger, and Australian snakes. The venoms contain polypeptide toxins of various kinds, cytolytic, hemolytic, and neurotoxic factors, but fewer enzymes than viper or crotalid venoms. Many of the toxins have been characterized.
Stable potassium atoms that have the same atomic number as the element potassium, but differ in atomic weight. K-41 is a stable potassium isotope.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
A subgroup of TRP cation channels named after vanilloid receptor. They are very sensitive to TEMPERATURE and hot spicy food and CAPSAICIN. They have the TRP domain and ANKYRIN repeats. Selectivity for CALCIUM over SODIUM ranges from 3 to 100 fold.
10-carbon saturated monocarboxylic acids.
A subgroup of TRP cation channels named after melastatin protein. They have the TRP domain but lack ANKYRIN repeats. Enzyme domains in the C-terminus leads to them being called chanzymes.
Organic compounds containing both the hydroxyl and carboxyl radicals.
The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.
Established cell cultures that have the potential to propagate indefinitely.
Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.
A delayed rectifier subtype of shaker potassium channels that has been described in NEURONS and ASTROCYTES.
An element that is an alkali metal. It has an atomic symbol Rb, atomic number 37, and atomic weight 85.47. It is used as a chemical reagent and in the manufacture of photoelectric cells.
A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.
Unstable isotopes of potassium that decay or disintegrate emitting radiation. K atoms with atomic weights 37, 38, 40, and 42-45 are radioactive potassium isotopes.
Inorganic compounds derived from hydrochloric acid that contain the Cl- ion.
Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.
A family of neuronal calcium-sensor proteins that interact with and regulate potassium channels, type A.
CELL LINE derived from the ovary of the Chinese hamster, Cricetulus griseus (CRICETULUS). The species is a favorite for cytogenetic studies because of its small chromosome number. The cell line has provided model systems for the study of genetic alterations in cultured mammalian cells.
Arthropods of the order Scorpiones, of which 1500 to 2000 species have been described. The most common live in tropical or subtropical areas. They are nocturnal and feed principally on insects and other arthropods. They are large arachnids but do not attack man spontaneously. They have a venomous sting. Their medical significance varies considerably and is dependent on their habits and venom potency rather than on their size. At most, the sting is equivalent to that of a hornet but certain species possess a highly toxic venom potentially fatal to humans. (From Dorland, 27th ed; Smith, Insects and Other Arthropods of Medical Importance, 1973, p417; Barnes, Invertebrate Zoology, 5th ed, p503)
A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.
An actinomycete used for production of commercial ANTIBIOTICS and as a host for gene cloning.
A condition that is characterized by episodes of fainting (SYNCOPE) and varying degree of ventricular arrhythmia as indicated by the prolonged QT interval. The inherited forms are caused by mutation of genes encoding cardiac ion channel proteins. The two major forms are ROMANO-WARD SYNDROME and JERVELL-LANGE NIELSEN SYNDROME.
The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow.
Elements of limited time intervals, contributing to particular results or situations.
Drugs used to cause dilation of the blood vessels.
A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.
The uptake of naked or purified DNA by CELLS, usually meaning the process as it occurs in eukaryotic cells. It is analogous to bacterial transformation (TRANSFORMATION, BACTERIAL) and both are routinely employed in GENE TRANSFER TECHNIQUES.
A broad group of eukaryotic six-transmembrane cation channels that are classified by sequence homology because their functional involvement with SENSATION is varied. They have only weak voltage sensitivity and ion selectivity. They are named after a DROSOPHILA mutant that displayed transient receptor potentials in response to light. A 25-amino-acid motif containing a TRP box (EWKFAR) just C-terminal to S6 is found in TRPC, TRPV and TRPM subgroups. ANKYRIN repeats are found in TRPC, TRPV & TRPN subgroups. Some are functionally associated with TYROSINE KINASE or TYPE C PHOSPHOLIPASES.
The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
A cell line generated from human embryonic kidney cells that were transformed with human adenovirus type 5.
Pyridines substituted in any position with an amino group. May be hydrogenated, but must retain at least one double bond.
Use of electric potential or currents to elicit biological responses.
CALCIUM CHANNELS located within the PURKINJE CELLS of the cerebellum. They are involved in stimulation-secretion coupling of neurons.
A group of compounds that are monomethyl derivatives of pyridines. (From Dorland, 28th ed)
A potent direct-acting peripheral vasodilator (VASODILATOR AGENTS) that reduces peripheral resistance and produces a fall in BLOOD PRESSURE. (From Martindale, The Extra Pharmacopoeia, 30th ed, p371)
The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).
An aminoperhydroquinazoline poison found mainly in the liver and ovaries of fishes in the order TETRAODONTIFORMES, which are eaten. The toxin causes paresthesia and paralysis through interference with neuromuscular conduction.
Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.
A superorder of CEPHALOPODS comprised of squid, cuttlefish, and their relatives. Their distinguishing feature is the modification of their fourth pair of arms into tentacles, resulting in 10 limbs.
A subgroup of cyclic nucleotide-regulated ION CHANNELS of the superfamily of pore-loop cation channels that are opened by hyperpolarization rather than depolarization. The ion conducting pore passes SODIUM, CALCIUM, and POTASSIUM cations with a preference for potassium.
Membrane proteins whose primary function is to facilitate the transport of positively charged molecules (cations) across a biological membrane.
An atom or group of atoms that have a positive or negative electric charge due to a gain (negative charge) or loss (positive charge) of one or more electrons. Atoms with a positive charge are known as CATIONS; those with a negative charge are ANIONS.
The parts of a macromolecule that directly participate in its specific combination with another molecule.
Positively charged atoms, radicals or groups of atoms which travel to the cathode or negative pole during electrolysis.
Abnormally low potassium concentration in the blood. It may result from potassium loss by renal secretion or by the gastrointestinal route, as by vomiting or diarrhea. It may be manifested clinically by neuromuscular disorders ranging from weakness to paralysis, by electrocardiographic abnormalities (depression of the T wave and elevation of the U wave), by renal disease, and by gastrointestinal disorders. (Dorland, 27th ed)
The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.
An inorganic compound that is used as a source of iodine in thyrotoxic crisis and in the preparation of thyrotoxic patients for thyroidectomy. (From Dorland, 27th ed)
A family of MEMBRANE TRANSPORT PROTEINS that require ATP hydrolysis for the transport of substrates across membranes. The protein family derives its name from the ATP-binding domain found on the protein.
The hollow, muscular organ that maintains the circulation of the blood.
The study of PHYSICAL PHENOMENA and PHYSICAL PROCESSES as applied to living things.
A quality of cell membranes which permits the passage of solvents and solutes into and out of cells.
Synthetic transcripts of a specific DNA molecule or fragment, made by an in vitro transcription system. This cRNA can be labeled with radioactive uracil and then used as a probe. (King & Stansfield, A Dictionary of Genetics, 4th ed)
An optical isomer of quinine, extracted from the bark of the CHINCHONA tree and similar plant species. This alkaloid dampens the excitability of cardiac and skeletal muscles by blocking sodium and potassium currents across cellular membranes. It prolongs cellular ACTION POTENTIALS, and decreases automaticity. Quinidine also blocks muscarinic and alpha-adrenergic neurotransmission.
The physiological widening of BLOOD VESSELS by relaxing the underlying VASCULAR SMOOTH MUSCLE.
A voltage-gated sodium channel subtype that mediates the sodium ion PERMEABILITY of CARDIOMYOCYTES. Defects in the SCN5A gene, which codes for the alpha subunit of this sodium channel, are associated with a variety of CARDIAC DISEASES that result from loss of sodium channel function.
CALCIUM CHANNELS located in the neurons of the brain.
Agents used for the treatment or prevention of cardiac arrhythmias. They may affect the polarization-repolarization phase of the action potential, its excitability or refractoriness, or impulse conduction or membrane responsiveness within cardiac fibers. Anti-arrhythmia agents are often classed into four main groups according to their mechanism of action: sodium channel blockade, beta-adrenergic blockade, repolarization prolongation, or calcium channel blockade.
A sulphonylurea hypoglycemic agent with actions and uses similar to those of CHLORPROPAMIDE. (From Martindale, The Extra Pharmacopoeia, 30th ed, p290)
Venoms from jellyfish; CORALS; SEA ANEMONES; etc. They contain hemo-, cardio-, dermo- , and neuro-toxic substances and probably ENZYMES. They include palytoxin, sarcophine, and anthopleurine.
The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.
Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are linear polypeptides that are normally synthesized on RIBOSOMES.
Derivatives of ammonium compounds, NH4+ Y-, in which all four of the hydrogens bonded to nitrogen have been replaced with hydrocarbyl groups. These are distinguished from IMINES which are RN=CR2.
Proteins prepared by recombinant DNA technology.
The nonstriated involuntary muscle tissue of blood vessels.
A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.
A potent vasodilator agent with calcium antagonistic action. It is a useful anti-anginal agent that also lowers blood pressure.
Layers of lipid molecules which are two molecules thick. Bilayer systems are frequently studied as models of biological membranes.
Unstable isotopes of rubidium that decay or disintegrate emitting radiation. Rb atoms with atomic weights 79-84, and 86-95 are radioactive rubidium isotopes.
A tetrameric calcium release channel in the SARCOPLASMIC RETICULUM membrane of SMOOTH MUSCLE CELLS, acting oppositely to SARCOPLASMIC RETICULUM CALCIUM-TRANSPORTING ATPASES. It is important in skeletal and cardiac excitation-contraction coupling and studied by using RYANODINE. Abnormalities are implicated in CARDIAC ARRHYTHMIAS and MUSCULAR DISEASES.
A genus of the family Muridae consisting of eleven species. C. migratorius, the grey or Armenian hamster, and C. griseus, the Chinese hamster, are the two species used in biomedical research.
RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.
The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.
The physical characteristics and processes of biological systems.
Positively charged atoms, radicals or group of atoms with a valence of plus 1, which travel to the cathode or negative pole during electrolysis.
The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.
A voltage-gated sodium channel subtype that mediates the sodium ion permeability of excitable membranes. Defects in the SCN2A gene which codes for the alpha subunit of this sodium channel are associated with benign familial infantile seizures type 3, and early infantile epileptic encephalopathy type 11.
The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.
A powder that dissolves in water, which is administered orally, and is used as a diuretic, expectorant, systemic alkalizer, and electrolyte replenisher.
Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.
The level of protein structure in which regular hydrogen-bond interactions within contiguous stretches of polypeptide chain give rise to alpha helices, beta strands (which align to form beta sheets) or other types of coils. This is the first folding level of protein conformation.
The naturally occurring or experimentally induced replacement of one or more AMINO ACIDS in a protein with another. If a functionally equivalent amino acid is substituted, the protein may retain wild-type activity. Substitution may also diminish, enhance, or eliminate protein function. Experimentally induced substitution is often used to study enzyme activities and binding site properties.
The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)
CALCIUM CHANNELS located in the neurons of the brain. They are inhibited by the marine snail toxin, omega conotoxin MVIIC.
Nerve fibers that are capable of rapidly conducting impulses away from the neuron cell body.
A family of iminourea derivatives. The parent compound has been isolated from mushrooms, corn germ, rice hulls, mussels, earthworms, and turnip juice. Derivatives may have antiviral and antifungal properties.
CELL LINES derived from the CV-1 cell line by transformation with a replication origin defective mutant of SV40 VIRUS, which codes for wild type large T antigen (ANTIGENS, POLYOMAVIRUS TRANSFORMING). They are used for transfection and cloning. (The CV-1 cell line was derived from the kidney of an adult male African green monkey (CERCOPITHECUS AETHIOPS).)
A rare neuromuscular disorder with onset usually in late childhood or early adulthood, characterized by intermittent or continuous widespread involuntary muscle contractions; FASCICULATION; hyporeflexia; MUSCLE CRAMP; MUSCLE WEAKNESS; HYPERHIDROSIS; TACHYCARDIA; and MYOKYMIA. Involvement of pharyngeal or laryngeal muscles may interfere with speech and breathing. The continuous motor activity persists during sleep and general anesthesia (distinguishing this condition from STIFF-PERSON SYNDROME). Familial and acquired (primarily autoimmune) forms have been reported. (From Ann NY Acad Sci 1998 May 13;841:482-496; Adams et al., Principles of Neurology, 6th ed, p1491)
Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.
Striated muscle cells found in the heart. They are derived from cardiac myoblasts (MYOBLASTS, CARDIAC).
Abnormally high potassium concentration in the blood, most often due to defective renal excretion. It is characterized clinically by electrocardiographic abnormalities (elevated T waves and depressed P waves, and eventually by atrial asystole). In severe cases, weakness and flaccid paralysis may occur. (Dorland, 27th ed)
Toxic substances from microorganisms, plants or animals that interfere with the functions of the nervous system. Most venoms contain neurotoxic substances. Myotoxins are included in this concept.
A paraneoplastic syndrome marked by degeneration of neurons in the LIMBIC SYSTEM. Clinical features include HALLUCINATIONS, loss of EPISODIC MEMORY; ANOSMIA; AGEUSIA; TEMPORAL LOBE EPILEPSY; DEMENTIA; and affective disturbance (depression). Circulating anti-neuronal antibodies (e.g., anti-Hu; anti-Yo; anti-Ri; and anti-Ma2) and small cell lung carcinomas or testicular carcinoma are frequently associated with this syndrome.
Pyridine moieties which are partially saturated by the addition of two hydrogen atoms in any position.
The excitable plasma membrane of a muscle cell. (Glick, Glossary of Biochemistry and Molecular Biology, 1990)
A neurotransmitter found at neuromuscular junctions, autonomic ganglia, parasympathetic effector junctions, a subset of sympathetic effector junctions, and at many sites in the central nervous system.
Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction.
The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.
A curved elevation of GRAY MATTER extending the entire length of the floor of the TEMPORAL HORN of the LATERAL VENTRICLE (see also TEMPORAL LOBE). The hippocampus proper, subiculum, and DENTATE GYRUS constitute the hippocampal formation. Sometimes authors include the ENTORHINAL CORTEX in the hippocampal formation.
A family of membrane proteins that selectively conduct SODIUM ions due to changes in the TRANSMEMBRANE POTENTIAL DIFFERENCE. They typically have a multimeric structure with a core alpha subunit that defines the sodium channel subtype and several beta subunits that modulate sodium channel activity.
Recombinant proteins produced by the GENETIC TRANSLATION of fused genes formed by the combination of NUCLEIC ACID REGULATORY SEQUENCES of one or more genes with the protein coding sequences of one or more genes.
Property of membranes and other structures to permit passage of light, heat, gases, liquids, metabolites, and mineral ions.
Unstriated and unstriped muscle, one of the muscles of the internal organs, blood vessels, hair follicles, etc. Contractile elements are elongated, usually spindle-shaped cells with centrally located nuclei. Smooth muscle fibers are bound together into sheets or bundles by reticular fibers and frequently elastic nets are also abundant. (From Stedman, 25th ed)
Permanganic acid (HMnO4), potassium salt. A highly oxidative, water-soluble compound with purple crystals, and a sweet taste. (From McGraw-Hill Dictionary of Scientific and Technical Information, 4th ed)
A variety of neuromuscular conditions resulting from MUTATIONS in ION CHANNELS manifesting as episodes of EPILEPSY; HEADACHE DISORDERS; and DYSKINESIAS.
A group of peptide antibiotics from BACILLUS brevis. Gramicidin C or S is a cyclic, ten-amino acid polypeptide and gramicidins A, B, D are linear. Gramicidin is one of the two principal components of TYROTHRICIN.
A condition marked by recurrent seizures that occur during the first 4-6 weeks of life despite an otherwise benign neonatal course. Autosomal dominant familial and sporadic forms have been identified. Seizures generally consist of brief episodes of tonic posturing and other movements, apnea, eye deviations, and blood pressure fluctuations. These tend to remit after the 6th week of life. The risk of developing epilepsy at an older age is moderately increased in the familial form of this disorder. (Neurologia 1996 Feb;11(2):51-5)
A group of enzymes that are dependent on CYCLIC AMP and catalyze the phosphorylation of SERINE or THREONINE residues on proteins. Included under this category are two cyclic-AMP-dependent protein kinase subtypes, each of which is defined by its subunit composition.
The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.
The process of moving proteins from one cellular compartment (including extracellular) to another by various sorting and transport mechanisms such as gated transport, protein translocation, and vesicular transport.
Azoles of one NITROGEN and two double bonds that have aromatic chemical properties.
Interstitial space between cells, occupied by INTERSTITIAL FLUID as well as amorphous and fibrous substances. For organisms with a CELL WALL, the extracellular space includes everything outside of the CELL MEMBRANE including the PERIPLASM and the cell wall.
The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.
A phosphoinositide present in all eukaryotic cells, particularly in the plasma membrane. It is the major substrate for receptor-stimulated phosphoinositidase C, with the consequent formation of inositol 1,4,5-triphosphate and diacylglycerol, and probably also for receptor-stimulated inositol phospholipid 3-kinase. (Kendrew, The Encyclopedia of Molecular Biology, 1994)
The electrical properties, characteristics of living organisms, and the processes of organisms or their parts that are involved in generating and responding to electrical charges.

Leptin suppression of insulin secretion and gene expression in human pancreatic islets: implications for the development of adipogenic diabetes mellitus. (1/9961)

Previously we demonstrated the expression of the long form of the leptin receptor in rodent pancreatic beta-cells and an inhibition of insulin secretion by leptin via activation of ATP-sensitive potassium channels. Here we examine pancreatic islets isolated from pancreata of human donors for their responses to leptin. The presence of leptin receptors on islet beta-cells was demonstrated by double fluorescence confocal microscopy after binding of a fluorescent derivative of human leptin (Cy3-leptin). Leptin (6.25 nM) suppressed insulin secretion of normal islets by 20% at 5.6 mM glucose. Intracellular calcium responses to 16.7 mM glucose were rapidly reduced by leptin. Proinsulin messenger ribonucleic acid expression in islets was inhibited by leptin at 11.1 mM, but not at 5.6 mM glucose. Leptin also reduced proinsulin messenger ribonucleic acid levels that were increased in islets by treatment with 10 nM glucagon-like peptide-1 in the presence of either 5.6 or 11.1 mM glucose. These findings demonstrate direct suppressive effects of leptin on insulin-producing beta-cells in human islets at the levels of both stimulus-secretion coupling and gene expression. The findings also further indicate the existence of an adipoinsular axis in humans in which insulin stimulates leptin production in adipocytes and leptin inhibits the production of insulin in beta-cells. We suggest that dysregulation of the adipoinsular axis in obese individuals due to defective leptin reception by beta-cells may result in chronic hyperinsulinemia and may contribute to the pathogenesis of adipogenic diabetes.  (+info)

Alternative sulfonylurea receptor expression defines metabolic sensitivity of K-ATP channels in dopaminergic midbrain neurons. (2/9961)

ATP-sensitive potassium (K-ATP) channels couple the metabolic state to cellular excitability in various tissues. Several isoforms of the K-ATP channel subunits, the sulfonylurea receptor (SUR) and inwardly rectifying K channel (Kir6.X), have been cloned, but the molecular composition and functional diversity of native neuronal K-ATP channels remain unresolved. We combined functional analysis of K-ATP channels with expression profiling of K-ATP subunits at the level of single substantia nigra (SN) neurons in mouse brain slices using an RT-multiplex PCR protocol. In contrast to GABAergic neurons, single dopaminergic SN neurons displayed alternative co-expression of either SUR1, SUR2B or both SUR isoforms with Kir6.2. Dopaminergic SN neurons expressed alternative K-ATP channel species distinguished by significant differences in sulfonylurea affinity and metabolic sensitivity. In single dopaminergic SN neurons, co-expression of SUR1 + Kir6.2, but not of SUR2B + Kir6.2, correlated with functional K-ATP channels highly sensitive to metabolic inhibition. In contrast to wild-type, surviving dopaminergic SN neurons of homozygous weaver mouse exclusively expressed SUR1 + Kir6.2 during the active period of dopaminergic neurodegeneration. Therefore, alternative expression of K-ATP channel subunits defines the differential response to metabolic stress and constitutes a novel candidate mechanism for the differential vulnerability of dopaminergic neurons in response to respiratory chain dysfunction in Parkinson's disease.  (+info)

Inward rectification in KATP channels: a pH switch in the pore. (3/9961)

Inward-rectifier potassium channels (Kir channels) stabilize the resting membrane potential and set a threshold for excitation in many types of cell. This function arises from voltage-dependent rectification of these channels due to blockage by intracellular polyamines. In all Kir channels studied to date, the voltage-dependence of rectification is either strong or weak. Here we show that in cardiac as well as in cloned KATP channels (Kir6.2 + sulfonylurea receptor) polyamine-mediated rectification is not fixed but changes with intracellular pH in the physiological range: inward-rectification is prominent at basic pH, while at acidic pH rectification is very weak. The pH-dependence of polyamine block is specific for KATP as shown in experiments with other Kir channels. Systematic mutagenesis revealed a titratable C-terminal histidine residue (H216) in Kir6.2 to be the structural determinant, and electrostatic interaction between this residue and polyamines was shown to be the molecular mechanism underlying pH-dependent rectification. This pH-dependent block of KATP channels may represent a novel and direct link between excitation and intracellular pH.  (+info)

Cloning and characterization of the promoters of the maxiK channel alpha and beta subunits. (4/9961)

Large conductance, calcium-activated potassium (maxiK) channels are expressed in nerve, muscle, and other cell types and are important determinants of smooth muscle tone. To determine the mechanisms involved in the transcriptional regulation of maxiK channels, we characterized the promoter regions of the pore forming (alpha) and regulatory (beta) subunits of the human channel complex. Maximum promoter activity (up to 12.3-fold over control) occurred between nucleotides -567 and -220 for the alpha subunit (hSlo) gene. The minimal promoter is GC-rich with 5 Sp-1 binding sites and several TCC repeats. Other transcription factor-binding motifs, including c/EBP, NF-kB, PU.1, PEA-3, Myo-D, and E2A, were observed in the 5'-flanking sequence. Additionally, a CCTCCC sequence, which increases the transcriptional activity of the SM1/2 gene in smooth muscle, is located 27 bp upstream of the TATA-like sequence, a location identical to that found in the SM1/2 5'-flanking region. However, the promoter directed equivalent expression when transfected into smooth muscle and other cell types. Analysis of the hSlo beta subunit 5'-flanking region revealed a TATA box at position -77 and maximum promoter activity (up to 11.0-fold) in a 200 bp region upstream from the cap site. Binding sites for GATA-1, Myo-D, c-myb, Ets-1/Elk-1, Ap-1, and Ik-2 were identified within this sequence. Two CCTCCC elements are present in the hSlo beta subunit promoter, but tissue-specific transcriptional activity was not observed. The lack of tissue-specific promoter activity, particularly the finding of promoter activity in cells from tissues in which the maxiK gene is not expressed, suggests a complex channel regulatory mechanism for hSlo genes. Moreover, the lack of similarity of the promoters of the two genes suggests that regulation of coordinate expression of the subunits does not occur through equivalent cis-acting sequences.  (+info)

Genomic organization of the KCNQ1 K+ channel gene and identification of C-terminal mutations in the long-QT syndrome. (5/9961)

The voltage-gated K+ channel KVLQT1 is essential for the repolarization phase of the cardiac action potential and for K+ homeostasis in the inner ear. Mutations in the human KCNQ1 gene encoding the alpha subunit of the KVLQT1 channel cause the long-QT syndrome (LQTS). The autosomal dominant form of this cardiac disease, the Romano-Ward syndrome, is characterized by a prolongation of the QT interval, ventricular arrhythmias, and sudden death. The autosomal recessive form, the Jervell and Lange-Nielsen syndrome, also includes bilateral deafness. In the present study, we report the entire genomic structure of KCNQ1, which consists of 19 exons spanning 400 kb on chromosome 11p15.5. We describe the sequences of exon-intron boundaries and oligonucleotide primers that allow polymerase chain reaction (PCR) amplification of exons from genomic DNA. Two new (CA)n repeat microsatellites were found in introns 10 and 14. The present study provides helpful tools for the linkage analysis and mutation screening of the complete KCNQ1 gene. By use of these tools, five novel mutations were identified in LQTS patients by PCR-single-strand conformational polymorphism (SSCP) analysis in the C-terminal part of KCNQ1: two missense mutations, a 20-bp and 1-bp deletions, and a 1-bp insertion. Such mutations in the C-terminal domain of the gene may be more frequent than previously expected, because this region has not been analyzed so far. This could explain the low percentage of mutations found in large LQTS cohorts.  (+info)

Angiotensin II type 1 receptor-mediated inhibition of K+ channel subunit kv2.2 in brain stem and hypothalamic neurons. (6/9961)

Angiotensin II (Ang II) has powerful modulatory actions on cardiovascular function that are mediated by specific receptors located on neurons within the hypothalamus and brain stem. Incubation of neuronal cocultures of rat hypothalamus and brain stem with Ang II elicits an Ang II type 1 (AT1) receptor-mediated inhibition of total outward K+ current that contributes to an increase in neuronal firing rate. However, the exact K+ conductance(s) that is inhibited by Ang II are not established. Pharmacological manipulation of total neuronal outward K+ current revealed a component of K+ current sensitive to quinine, tetraethylammonium, and 4-aminopyridine, with IC50 values of 21.7 micromol/L, 1.49 mmol/L, and 890 micromol/L, respectively, and insensitive to alpha-dendrotoxin (100 to 500 nmol/L), charybdotoxin (100 to 500 nmol/L), and mast cell degranulating peptide (1 micromol/L). Collectively, these data suggest the presence of Kv2.2 and Kv3.1b. Biophysical examination of the quinine-sensitive neuronal K+ current demonstrated a macroscopic conductance with similar biophysical properties to those of Kv2.2 and Kv3.1b. Ang II (100 nmol/L), in the presence of the AT2 receptor blocker PD123,319, elicited an inhibition of neuronal K+ current that was abolished by quinine (50 micromol/L). Reverse transcriptase-polymerase chain reaction analysis confirmed the presence of Kv2.2 and Kv3.1b mRNA in these neurons. However, Western blot analyses demonstrated that only Kv2.2 protein was present. Coexpression of Kv2.2 and the AT1 receptor in Xenopus oocytes demonstrated an Ang II-induced inhibition of Kv2.2 current. Therefore, these data suggest that inhibition of Kv2.2 contributes to the AT1 receptor-mediated reduction of neuronal K+ current and subsequently to the modulation of cardiovascular function.  (+info)

Ionic currents underlying spontaneous action potentials in isolated cerebellar Purkinje neurons. (7/9961)

Acutely dissociated cell bodies of mouse Purkinje neurons spontaneously fired action potentials at approximately 50 Hz (25 degrees C). To directly measure the ionic currents underlying spontaneous activity, we voltage-clamped the cells using prerecorded spontaneous action potentials (spike trains) as voltage commands and used ionic substitution and selective blockers to isolate individual currents. The largest current flowing during the interspike interval was tetrodotoxin-sensitive sodium current (approximately -50 pA between -65 and -60 mV). Although the neurons had large voltage-dependent calcium currents, the net current blocked by cobalt substitution for calcium was outward at all times during spike trains. Thus, the electrical effect of calcium current is apparently dominated by rapidly activated calcium-dependent potassium currents. Under current clamp, all cells continued firing spontaneously (though approximately 30% more slowly) after block of T-type calcium current by mibefradil, and most cells continued to fire after block of all calcium current by cobalt substitution. Although the neurons possessed hyperpolarization-activated cation current (Ih), little current flowed during spike trains, and block by 1 mM cesium had no effect on firing frequency. The outward potassium currents underlying the repolarization of the spikes were completely blocked by 1 mM TEA. These currents deactivated quickly (<1 msec) after each spike. We conclude that the spontaneous firing of Purkinje neuron cell bodies depends mainly on tetrodotoxin-sensitive sodium current flowing between spikes. The high firing rate is promoted by large potassium currents that repolarize the cell rapidly and deactivate quickly, thus preventing strong hyperpolarization and restoring a high input resistance for subsequent depolarization.  (+info)

Inducible genetic suppression of neuronal excitability. (8/9961)

Graded, reversible suppression of neuronal excitability represents a logical goal of therapy for epilepsy and intractable pain. To achieve such suppression, we have developed the means to transfer "electrical silencing" genes into neurons with sensitive control of transgene expression. An ecdysone-inducible promoter drives the expression of inwardly rectifying potassium channels in polycistronic adenoviral vectors. Infection of superior cervical ganglion neurons did not affect normal electrical activity but suppressed excitability after the induction of gene expression. These experiments demonstrate the feasibility of controlled ion channel expression after somatic gene transfer into neurons and serve as the prototype for a novel generalizable approach to modulate excitability.  (+info)

TY - JOUR. T1 - ATP sensitive potassium channel openers. T2 - A new class of ocular hypotensive agents. AU - Roy Chowdhury, Uttio. AU - Dosa, Peter I.. AU - Fautsch, Michael P. PY - 2016/3/2. Y1 - 2016/3/2. N2 - ATP sensitive potassium (KATP) channels connect the metabolic and energetic state of cells due to their sensitivity to ATP and ADP concentrations. KATP channels have been identified in multiple tissues and organs of the body including heart, pancreas, vascular smooth muscles and skeletal muscles. These channels are obligatory hetero-octamers and contain four sulfonylurea (SUR) and four potassium inward rectifier (Kir) subunits. Based on the particular type of SUR and Kir present, there are several tissue specific subtypes of KATP channels, each with their own unique set of functions. Recently, KATP channels have been reported in human and mouse ocular tissues. In ex vivo and in vivo model systems, KATP channel openers showed significant ocular hypotensive properties with no appearance of ...
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TY - JOUR. T1 - The Role of the Voltage-Gated Potassium Channel Proteins Kv8.2 and Kv2.1 in Vision and Retinal Disease. T2 - Insights from the Study of Mouse Gene Knock-Out Mutations. AU - Hart, Nathan S. AU - Mountford, Jessica K. AU - Voigt, Valentina. AU - Fuller-Carter, Paula. AU - Barth, Melanie. AU - Nerbonne, Jeanne M. AU - Hunt, David M. AU - Carvalho, Livia S. PY - 2019/2. Y1 - 2019/2. N2 - Mutations in the KCNV2 gene, which encodes the voltage-gated K+ channel protein Kv8.2, cause a distinctive form of cone dystrophy with a supernormal rod response (CDSRR). Kv8.2 channel subunits only form functional channels when combined in a heterotetramer with Kv2.1 subunits encoded by the KCNB1 gene. The CDSRR disease phenotype indicates that photoreceptor adaptation is disrupted. The electroretinogram (ERG) response of affected individuals shows depressed rod and cone activity, but what distinguishes this disease is the supernormal rod response to a bright flash of light. Here, we have utilized ...
Title: Targeting Potassium Channels: New Advances in Cardiovascular Therapy. VOLUME: 3 ISSUE: 2. Author(s):Ramon Martinez-Marmol, Meritxell Roura-Ferrer and Antonio Felipe. Affiliation:Molecular Physiology Laboratory, Departament de Bioquimica i Biologia Molecular, Universitat de Barcelona, E-08028 Barcelona, Spain.. Keywords:Potassium channels, cardiovascular therapy, channelopathy, long QT syndrome, arrithmiogenesis, heart diseases. Abstract: Potassium channels, which are essential to a wide range of physiological processes, are involved in many diseases. Thus, alterations in such important proteins due to congenital deficiencies or to undesirable side-effects of common medications might lead to dysfunctions. Heart is one of those tissues where potassium channels play a crucial role. The maintenance of cardiac action potential appears to be the consequence of the varied activity of several types of potassium channels. Recently, compounds that modify cardiac potassium channel activity and so ...
TY - JOUR. T1 - Blockade of ATP-sensitive potassium channels prevents the attenuation of the exercise pressor reflex by tempol in rats with ligated femoral arteries. AU - Yamauchi, Katsuya. AU - Stone, Audrey J.. AU - Stocker, Sean D.. AU - Kaufman, Marc P.. PY - 2012/8/1. Y1 - 2012/8/1. N2 - We reported previously that tempol attenuated the exercise pressor and muscle mechanoreceptor reflexes in rats whose femoral arteries were ligated, whereas tempol did not attenuate these reflexes in rats whose femoral arteries were freely perfused. Although the mechanism whereby tempol attenuated these reflexes in rats whose femoral artery was ligated was independent of its ability to scavenge reactive oxygen species, its nature remains unclear. An alternative explanation for the tempol-induced attenuation of these reflexes involves ATP-sensitive potassium channels (K Atp) and calcium-activated potassium channels (BK Ca), both of which are opened by tempol. We tested the likelihood of this explanation by ...
Potassium ion (K+) channels are ubiquitous components and are widely distributed on the surface of the cell membrane in various tissues. There are many types of potassium ion channels (voltage-gated K+ channels, ATP-sensitive K+ channels, Ca2+-activated K+ channels, etc.), and each type of potassium ion channel has its own characteristic features concerning electrophysiology and molecular biology in each potassium ion channel. The potassium ion current across the plasma membrane is considered to have two main physiological functions, one for determining the membrane potential and the other regulating the electrical activity. Membrane hyperpolarization would reduce the excitability of the membrane by shifting the membrane potential away from the threshold for excitation and would inhibit, where it existed, calcium ion (Ca2+) influx through voltage-gated Ca2+ channels by closing the Ca2+ channel. Outward potassium ion currents activated upon depolarization would counteract the depolarizing action ...
Carr DB, McDonnell Moorehead T, Bouchard A, et al. Effects of injectable HPβCD-diclofenac on the human delayed rectifier potassium channel current in vitro and on proarrhythmic QTc in vivo. Clin Ther. 2013;35(5):646-658. doi:10.1016/j.clinthera.2013.03.014. View article
TY - JOUR. T1 - Squaring the Circle. T2 - A New Study of Inward and Outward-Rectifying Potassium Currents in U251 GBM Cells. AU - Ratto, Daniela. AU - Ferrari, Beatrice. AU - Roda, Elisa. AU - Brandalise, Federico. AU - Siciliani, Stella. AU - De Luca, Fabrizio. AU - Priori, Erica Cecilia. AU - Di Iorio, Carmine. AU - Cobelli, Filippo. AU - Veneroni, Paola. AU - Bottone, Maria Grazia. AU - Rossi, Paola. PY - 2020/7. Y1 - 2020/7. N2 - In the present study, the functional role of the inwardly rectifying K+ channel, Kir4.1, and large-conductance Ca2+-activated K+ (BK) channel during cell migration in U251 cell line was investigated. We focused on polarised cells which are positive for the active-Cdc42 migration marker. The perforated patch technique was used to avoid intracellular dialysis and to maintain physiological changes in intracellular calcium. Wound healing was employed to assay migration after 24 h. Polarised cells recorded displayed different hallmarks of undifferentiated glial cells: ...
Transient exposure to ethanol (EtOH) results in a massive neurodegeneration in the developing brain leading to behavioral and cognitive deficits observed in fetal alcohol syndrome. There is now compelling evidence that K+ channels play an important role in the control of programmed cell death. The aim of the present work was to investigate the involvement of K+ channels in the EtOH-induced cerebellar granule cell death and/or survival. At low and high concentrations, EtOH evoked membrane depolarization and hyperpolarization, respectively. Bath perfusion of EtOH (10 mM) depressed the I(A) (transient K+ current) potassium current whereas EtOH (400 mM) provoked a marked potentiation of the specific I(K) (delayed rectifier K+ current) current. Pipette dialysis with GTPgammaS or GDPbetaS did not modify the effects of EtOH (400 mM) on both membrane potential and I(K) current. In contrast, the reversible depolarization and slowly recovering inhibition of I(A) induced by EtOH (10 mM) became irreversible in the
Most information currently available regarding vascular K+ channel function in diabetes concerns KATP channels. As for chronic hypertension, there are now several reports of impaired vascular relaxant responses to synthetic openers of KATP channels in long-term diabetes. These studies have mostly utilized the streptozotocin-injected rat model of diabetes and have examined vessels at 2.5 to 4 months after streptozotocin treatment. In this model in which plasma glucose levels are increased 3- to 4-fold, impaired relaxation of the isolated aorta122 123 124 and mesenteric vascular bed125 and reduced dilatation of large126 and small127 cerebral arteries in vivo typically develop. These changes are thought to be the result of a decreased number of vascular KATP channels and/or reduced sensitivity of these channels to synthetic openers. Nonspecific cytotoxic effects of streptozotocin seem an unlikely cause of these changes because, like other manifestations of vascular dysfunction, abnormal vasodilator ...
Most information currently available regarding vascular K+ channel function in diabetes concerns KATP channels. As for chronic hypertension, there are now several reports of impaired vascular relaxant responses to synthetic openers of KATP channels in long-term diabetes. These studies have mostly utilized the streptozotocin-injected rat model of diabetes and have examined vessels at 2.5 to 4 months after streptozotocin treatment. In this model in which plasma glucose levels are increased 3- to 4-fold, impaired relaxation of the isolated aorta122 123 124 and mesenteric vascular bed125 and reduced dilatation of large126 and small127 cerebral arteries in vivo typically develop. These changes are thought to be the result of a decreased number of vascular KATP channels and/or reduced sensitivity of these channels to synthetic openers. Nonspecific cytotoxic effects of streptozotocin seem an unlikely cause of these changes because, like other manifestations of vascular dysfunction, abnormal vasodilator ...
Potassium channel molecule. Computer model showing the structure of a bacterial potassium channel with four units arranged around an axis going through the first (and only visible) of four potassium ions (big purple sphere). From Bacillus cereus. - Stock Image C035/8257
A recent study (1) gives insight into how the lipids in the cell membranes affect how well one particular potassium channel functions. The particular channel the researchers investigated is one of the most studied potassium channels. This channel demonstrates how the function of other channels and pumps also may be affected by the composition of the cell membranes.. The researchers showed that the pore that lets potassium flow through the channel is fine-tuned by the physical characteristics of the lipid in the cell membrane. When the membrane allows protein in the pore of the channel to change more easily, potassium can get through faster.. This study changed two characteristics of the membrane that potassium channels sit in. The two characteristics of the membrane that the researchers changed were the temperature of the membrane, and the type of fats the membrane was made of. Both of these characteristics changed the fluidity of the membrane.. The researchers then determined whether the ...
An electrochemical gating model is presented to account for the effects described in the companion paper by M. R. Silver, M. S. Shapiro, and T. E. DeCoursey (1994. Journal of General Physiology, 103:519-548) of Rb+ and Rb+/K+ mixtures on the kinetics and voltage dependence of an inwardly rectifying (IR) K+ channel. The model proposes that both Rb+ and K+ act as allosteric modulators of an intrinsically voltage dependent isomerization between open and closed states. Occupancy of binding sites on the outside of the channel promotes channel opening and stabilizes the open state. Rb+ binds to separate sites within the pore and plugs IR channels. Occupancy of the pore by Rb+ can modify the rates of isomerization and the affinity of the allosteric sites for activator ions. The model also incorporates the proposed triple-barreled nature of the IR channel (Matsuda, H., 1988. Journal of Physiology. 397:237-258.) by proposing that plugging of the channel is a cooperative process involving a single site in ...
Global Markets Directs, Potassium Voltage Gated Channel Subfamily C Member 1 (Voltage Gated Potassium Channel Subunit Kv3.1 or Voltage Gated Potassium Channel Subunit Kv4 or KCNC1) - Pipeline
This enabled them to draw conclusions about its mechanism of action, which they describe in the current issue of Nature Communications. Neurons conduct information by way of electrical impulses through our body. Potassium channels are a key component of this electrical circuit and are controlled either by an electrical impulse or through signaling molecules. In man, the dysfunction of the so-called HCN potassium channels is associated with neurological disorders such as epilepsy and depression. Prof. Henning Stahlbergs team at the Biozentrum of the University of Basel has now elucidated the full structure of a bacterial counterpart of this type of potassium channel, which has provided new insights into its functioning.. ...
This e-book presents an overview of the different substances capable of modulating potassium channels in relation to various clinical indications in cardiology, pulmonology, endocrinology and neurology. The possible benefits and side effects of potassium channel modulators is discussed in correlation with biophysical and pharmacological properties of ion channels. Readers will learn how mutation of K+ channels can be conferred by molecular processes such as alternative splicing, RNA editing and posttranslational modifications. Altogether, this e-book will be of use to clinical practitioners, electrophysiologists and pharmacologists interested in the complicated but fascinating science of potassium channels.. ...
Energy dissipating systems (uncoupling proteins - UCPs, alternative oxidase - AOX, mitochondrial potassium channels) in physiological and pathological conditions: the activity of UCPs and AOXs in different eukaryotic organisms, UCP proteins in inflammation and circulatory diseases, mitochondrial potassium channels in cytoprotection, mitochondria and the endurance ...
July 29, 2013. Just 12 molecules of water cause the long post-activation recovery period required by potassium ion channels before they can function again. Using molecular simulations that modeled a potassium channel and its immediate cellular environment, atom for atom, University of Chicago scientists have revealed this new mechanism in the function of a nearly universal biological structure, with implications ranging from fundamental biology to the design of pharmaceuticals. Their findings were published online July 28 in Nature.. Our research clarifies the nature of this previously mysterious inactivation state. This gives us better understanding of fundamental biology and should improve the rational design of drugs, which often target the inactivated state of channels said Benoît Roux, PhD, professor of biochemistry and molecular biology at the University of Chicago.. Potassium channels, present in the cells of virtually all living organisms, are core components in bioelectricity ...
Effects of KRN4884 (5-amino-,i,N,/i,-[2-(2-chlorophenyl)ethyl]-,i,N,/i,-cyano-3-pyridinecarboxamidine), a novel K,sup,+,/sup, channel opener, on ionic currents were examined in rabbit femoral arterial myocytes (RFAMs). Under whole-cell clamp conditions where cells were superfused with 5.9 mM K,sup,+,/sup, bathing solution, KRN4884 elicited an outward current at −30 mV. KRN4884-induced current had a reversal potential of −78 mV and was abolished by application of glibenclamide (glib). KRN4884 was approximately 43 times more potent than levcromakalim in activating an ATP-sensitive K,sup,+,/sup, current (I,sub,K-ATP,/sub,). On the other hand, KRN4884 affected neither voltage-dependent Ca,sup,2+,/sup, nor delayed rectifier K,sup,+,/sup, channel currents. In the inside-out patch clamp configuration where cells were superfused with the symmetrical 140 mM K,sup,+,/sup, solution, KRN4884 activated 47 pS K,sup,+,/sup, channels in the presence of adenosine diphosphate. Similar 47 pS K,sup,+,/sup, ...
The following figure shows the location of the disease-causing mutations in hKv8.2 in CDSRE patients examined in this study. Three of these, W450G, G459D, and G461R, are located in the pore region of the hKv8.2 α-subunit. The missense mutations G459D and G461R affect the first and second glycine, respectively, of the Gly-Tyr-Gly motif, the characteristic potassium channel signature sequence. To understand the functional consequences of these mutations, the corresponding mutations (W467G, G476D, and G478R) were introduced into mKv8.2, and their effect on subunit localization in COS7L cells was examined. Like mKv8.2, the expression of either mKv8.2-W467G-EGFP, mKv8.2-G476D-EGFP, or mKv8.2-G478R-EGFP resulted in an intracellular localization [1753]. Voltage-gated K+ channels selectively transfer potassium ions through the plasma membrane in response to depolarization. The ion-conducting core of voltage-gated K+ channels is composed of four Kv-alpha subunits, which also possess the voltage sensor. ...
Fig. 2. KCNE1 inhibits KCNQ1 currents and depolarizes embryonic cells. (A) Tail currents were analyzed at −120 mV and normalized to the value followed after the 60-mV depolarizing pulse to estimate the voltage dependence of channel activation (n = 10 or 11). At voltages of 0 mV or less, addition of KCNE1 reduced the currents compared with KCNQ1 alone. (B) KCNQ1 (5 ng of mRNA) was expressed alone or together with 0.2 ng of KCNE1 mRNA. Each lane was loaded with equal amounts of protein (as estimated by Bradford test and Ponceau staining). Four consecutive biotinylation Western blots detected no clear alterations of KCNQ1 protein in the plasma membrane (densitometric analysis of all four gels normalized to the respective KCNQ1 band gave 1.0061 ± 0.1025 for KCNQ1 + KCNE1 injections). Analysis of membrane potential in vivo using DiSBAC voltage reporter dye reveals that KCNE1 mRNA expression depolarizes cells in the neurulating embryo. (C) Histograms showing normalized frequencies corresponding to ...
Potassium channels selectively conduct K(+) ions across cell membranes and have key roles in cell excitability. Their opening and closing can be spontaneous or controlled by membrane voltage or ligand binding. We used Ba(2+) as a probe to determine the location of the ligand-sensitive gate in an inwardly rectifying K(+) channel (Kir6.2). To a K(+) channel, Ba(2+) and K(+) are of similar sizes, but Ba(2+) blocks the pore by binding within the selectivity filter. We found that internal Ba(2+) could still access its binding site when the channel was shut, which indicates that the ligand-sensitive gate lies above the Ba(2+)-block site, and thus within or above the selectivity filter. This is in marked contrast to the voltage-dependent gate of K(V) channels, which is located at the intracellular mouth of the pore.
Gene Information Potassium channels are present in most mammalian cells where they participate in a wide range of physiologic responses. The protein encoded by this gene is an integral membrane protein and inward-rectifier type potassium channel. The encoded protein which has a greater tendency to allow potassium to flow into a cell rather than out of a cell is controlled by G-proteins. It associates with another G-protein-activated potassium channel to form a heteromultimeric pore-forming complex. [provided by RefSeq Jul 2008]. ...
This review has focused on the properties of the ATP-sensitive K-channel found in cardiac and skeletal muscle, and in pancreatic beta-cells. It is conceivable that this channel will be found in other cell types. In particular, it would be worthwhile looking for its presence in those cells in which electrical activity is linked to metabolism, glucose concentration, or oxygen levels. Obvious examples are the glucoreceptor neurons of mammalian brain and chemoreceptors such as those of the carotid body. While ATP-sensitive K-channels in cardiac and skeletal muscle membranes are rather similar, there are a few significant differences between these channels and that found in the beta-cell. Most notably, the latter is more sensitive to inhibition by ATP and sulphonylureas. It remains to be seen whether they also differ in the ability of nucleotides to activate the channel. Considerable confusion also still surrounds the physiological regulation of the ATP-sensitive K-channel in intact cells. Although the
This gene encodes one of the members of the superfamily of potassium channel proteins containing two pore-forming P domains. The message for this gene is mainly expressed in the cortical distal tubules and collecting ducts of the kidney. The protein is highly sensitive to external pH and this, in combination with its expression pattern, suggests it may play an important role in renal potassium transport ...
Potassium channel (Protein Data Bank entry 1bl8) on a dark slate blue background with potassium ions shown in firebrick. The channel is comprised of four chains. Each chain has been rainbow-colored from blue at the N-terminus to red at the C-terminus, but only the surface of the channel is shown. The surface has been sliced with a per-model clipping plane. The surface cap color is plum except with opacity set to 0.8. The shininess and brightness have been set to 128 and 8, respectively, and the lights on the scene have been moved from their default positions. The subdivision quality (related to the smoothness of the spherical ions) is 5.0, and the molecular surface was computed with probe radius and vertex density set to 1.0 and 6.0, respectively. The entry Cavity and Tunnel Detection provides additional views of the same structure. ...
This is the Authors Original Manuscript of an article published by Taylor & Francis in Channels on 02 Jan 2018 available online: https://doi.org/10.1080/19336950.2017.1412151 ...
KCTD21 (potassium channel tetramerization domain containing 21), Authors: Dessen P. Published in: Atlas Genet Cytogenet Oncol Haematol.
BioAssay record AID 2432 submitted by Johns Hopkins Ion Channel Center: Mode of action assay - molecular determinants for ztz240, a potentiator of KCNQ2 potassium channels.
Lipkind GM, Hanck DA, Fozzard HA. A structural motif for the voltage-gated potassium channel pore. Proc Natl Acad Sci U S A. 1995 Sep 26; 92(20):9215-9 ...
BioAssay record AID 2258 submitted by Johns Hopkins Ion Channel Center: Summary of probe development for potentiators of KCNQ2 potassium channels.
Kv1.2 Potassium Channel information including symptoms, causes, diseases, symptoms, treatments, and other medical and health issues.
High quality reagents for receptor, ion channel and enzyme research including potassium channel tools from Hello Bio - a trusted, affordable life science reagents supplier.
Differences in the mechanism of metabolic regulation of ATP-sensitive K+ channels containing Kir6.1 and Kir6.2 subunits.: Kir6.1\SUR2B has intrinsic sensitivity
心不全によるK_,ATP,チャネルの変調 : レシピエントから得た心筋による検討 Alterations in ATP-sensitive potassium channel sensitivity to ATP in failing human hearts ...
Experiments described in this report provide a strong argument for the existence of two distinct current components (I KF andI KS) in the slow sustained voltage-activated K+ current (I K) in the larval muscles ofDrosophila. Voltage-activated K+ current in the larval muscles ofDrosophila has been previously resolved into two distinct currents. With the data presented here, we can now resolve the total voltage-activated K+ current into three components. Resolution of I K intoI KS andI KF will be particularly helpful in analyzing the properties of these two currents, deciphering the functional role of each current in muscle excitability, and studying mechanisms underlying their function and regulation.. Channels carrying I KS are encoded by the Shab gene. I KS shares properties with the current generated by expressing Shabchannels in Xenopus oocytes. These properties include relative resistance to blockade by 4-AP and a relatively slow activation (Covarrubias et al., 1991; Tsunoda and Salkoff, ...
Our laboratory studies potassium channels which are key elements which control and shape electrical activity in the brain, heart, and other excitable tissues. These channels are major determinants of behavior and higher brain function. The potassium channels we study are involved in human disease (e.g. epilepsy, cardiac arrhythmia), basic physiology (e.g. control of blood pressure, protection from hypoxia), and higher brain function (e.g. learning and memory). Our approach is a comparative genom
This MATLAB function returns filtered state probabilities FS from conducting optimal conditional inference of the probabilities of the operative latent states in the regime-switching data Y.
Next-day shipping cDNA ORF clones derived from KCNE2 potassium voltage-gated channel subfamily E regulatory subunit 2 available at GenScript, starting from $99.00.
The protein encoded by this gene is part of a potentially heterotetrameric voltage-independent potassium channel that is activated by intracellular calcium. Activation is
Int. J. Mol. Sci. 2002, 3 193 where M= M AM B=(M A+ M B) is the reduced mass of the nuclei Aand Bwith corresponding masses M A and M B, R is the vector connecting the nuclei, r denotes the set of the electronic coordinates measured from the centre of nuclear mass, and H el(r;R) is the so-called electronic Hamiltonian, which contains operators of the kinetic energy for the electrons and all ...
Katso sanan specific käännös englanti-suomi. Ilmainen Sanakirja on monipuolinen sanakirja netissä. Suomi, englanti, ruotsi ja monta muuta kieltä!
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Euroopa Liidu L 215 Teataja Eestikeelne väljaanne Õigusaktid 61. aastakäik 23. august 2018 Sisukord III Muud aktid EUROOPA MAJANDUSPIIRKOND EMP ühiskomitee otsus nr 216/2016, millega muudetakse EMP lepingu
Tumor necrosis factor alpha modulates sodium-activated potassium channel SLICK in rat dorsal horn neurons via p38 MAPK activation pathway Kun Wang,1 Feng Wang,1 Jun-Ping Bao,2 Zhi-Yang Xie,1 Lu Chen,1 Bao-Yi Zhou,1 Xin-Hui Xie,2 Xiao-Tao Wu1,2 1Medical School of Southeast University, 2Department of Orthopaedics, Zhongda Hospital, Southeast University, Nanjing, Peopleâ s Republic of China Abstract: The dorsal horn (DH) of the spinal cord is the integrative center that processes and transmits pain sensation. Abnormal changes in ion channel expression can enhance the excitability of pain-related DH neurons. Sodium-activated potassium (KNa) channels are highly expressed particularly in the central nervous system; however, information about whether rat DH neurons express the SLICK channel protein is lacking, and the direct effects on SLICK in response to inflammation and the potential signaling pathway mediating such effects are yet to be elucidated. Here, using cultured DH neurons, we have shown that
This potassium channel is controlled by G proteins. Inward rectifier potassium channels are characterized by a greater tendency to allow potassium to flow into the cell rather than out of it. Their voltage dependence is regulated by the concentration of extracellular potassium; as external potassium is raised, the voltage range of the channel opening shifts to more positive voltages. The inward rectification is mainly due to the blockage of outward current by internal magnesium. Can be blocked by external barium (By similarity).
This receptor is controlled by G proteins. Inward rectifier potassium channels are characterized by a greater tendency to allow potassium to flow into the cell rather than out of it. Their voltage dependence is regulated by the concentration of extracellular potassium; as external potassium is raised, the voltage range of the channel opening shifts to more positive voltages. The inward rectification is mainly due to the blockage of outward current by internal magnesium. Can be blocked by extracellular barium. Can form cardiac and smooth muscle-type KATP channels with ABCC9. KCNJ11 forms the channel pore while ABCC9 is required for activation and regulation (By similarity).
Inward rectifier potassium channels are characterized by a greater tendency to allow potassium to flow into the cell rather than out of it. Their voltage dependence is regulated by the concentration of extracellular potassium; as external potassium is raised, the voltage range of the channel opening shifts to more positive voltages. The inward rectification is mainly due to the blockage of outward current by internal magnesium. KCNJ16 may be involved in the regulation of fluid and pH balance. In the kidney, together with KCNJ10, mediates basolateral K(+) recycling in distal tubules; this process is critical for Na(+) reabsorption at the tubules (PubMed:24561201 ...
Fluothane (halothane) is a small molecule pharmaceutical. Halothane was first approved as Fluothane on 1982-01-01. It is used to treat status asthmaticus in the USA. The pharmaceutical is active against potassium channel subfamily K member 9 and potassium channel subfamily K member 10. In addition, it is known to target potassium channel subfamily K member 2, potassium channel subfamily K member 12, potassium channel subfamily K member 3, potassium channel subfamily K member 5, potassium channel subfamily K member 13, potassium voltage-gated channel subfamily B member 1, G protein-activated inward rectifier potassium channel 2, and ferritin light chain.
Potassium channels, found throughout the animal and plant kingdoms, play important roles in maintaining membrane potentials and regulating action potential firing, shape, and duration, among other functions. Using the Xenopus laevis (frog) oocyte as model system, we induced high expression of sodium and potassium voltage-gated channels and recorded action potentials by a modification of the two-electrode voltage-clamp recording technique. The voltage-dependent sodium conductance was due to expression of the skeletal muscle NaV channel (NaV1.4) and the delayed rectifier voltage-dependent potassium conductance was due to expression of a Shaker (Kv1) potassium channel. Upon this background, we mixed different potassium-selective ion channels, such as inwardly rectifying potassium (KIR) channels, tandem pore domain (K2P) potassium channels and voltage-gated (KV) channels. We analyzed how these potassium channels affected firing thresholds, reliability of action potential generation, action potential
OBJECTIVE: To assess the influence of blocking smooth muscle large conductance Ca(2+) -activated K+ channels and voltage-gated K+ channels on the conducted dilation to ACh and isoproterenol. MATERIALS AND METHODS: Rat mesenteric arteries were isolated with a bifurcation, triple-cannulated, pressurized and imaged using confocal microscopy. Phenylephrine was added to the superfusate to generate tone, and agonists perfused into a sidebranch to evoke local dilation and subsequent conducted dilation into the feed artery. RESULTS: Both ACh- and isoproterenol-stimulated local and conducted dilation with similar magnitudes of decay with distance along the feed artery (2000μm: ∼15% maximum dilation). The gap junction uncoupler carbenoxolone prevented both conducted dilation and intercellular spread of dye through gap junctions. IbTx, TEA or 4-AP, blockers of large conductance Ca(2+) -activated K+ channels and voltage-gated K+ channels, did not affect conducted dilation to either agonist. A combination
TY - JOUR. T1 - Spontaneous contractions of the pig urinary bladder. T2 - The effect of ATP-sensitive potassium channels and the role of the mucosa. AU - Akino, Hironobu. AU - Chapple, Christopher R.. AU - McKay, Neil G.. AU - Cross, Rebecca L.. AU - Murakami, Shigetaka. AU - Yokoyama, Osamu. AU - Chess-Williams, Russell. AU - Sellers, Donna J.. PY - 2008/11. Y1 - 2008/11. N2 - OBJECTIVE: To investigate the influence of the mucosa on the inhibitory effects of the ATP-sensitive potassium channel (KATP channel) opener, cromakalim, on the spontaneous contractions of pig bladder strips from the bladder dome and trigone. Little is known about the influence of the mucosa on spontaneous contractions and whether the nature of these contractions differs between the bladder dome and trigone. MATERIALS AND METHODS: Paired longitudinal strips of female pig bladders were isolated from the dome and trigone. The mucosa was removed from one strip per pair and tissues were set up in organ baths. Spontaneous ...
The ATP-dependent potassium channels (KATP channels) were originally identified in isolated membrane patches prepared from guinea pig ventricular myocytes by Noma1 in 1983. Since their discovery in cardiac cells, KATP channels have also been discovered in many other tissues, such as smooth muscle, skeletal muscle, pancreas, and brain, in which they have been shown to couple cellular metabolism to membrane electrical activity.2 Primarily on the basis of studies using pharmacological tools, openers of KATP channels have been shown to elicit cardioprotective effects, whereas KATP channel antagonists have been shown to block the cardioprotective effects of KATP channel openers and the powerful protective effect produced by single or multiple brief episodes of ischemia to reduce myocardial infarct size, a phenomenon called ischemic preconditioning.3 Because the results of these previous studies were obtained indirectly by the use of pharmacological agonists and antagonists, the results of the present ...
TY - JOUR. T1 - Voltage-dependent potassium currents during fast spikes of rat cerebellar Purkinje neurons. T2 - Inhibition by BDS-I toxin. AU - Martina, Marco. AU - Metz, Alexia E.. AU - Bean, Bruce P.. PY - 2007/1/1. Y1 - 2007/1/1. N2 - We characterized the kinetics and pharmacological properties of voltage-activated potassium currents in rat cerebellar Purkinje neurons using recordings from nucleated patches, which allowed high resolution of activation and deactivation kinetics. Activation was exceptionally rapid, with 10-90% activation in about 400 μs at +30 mV, near the peak of the spike. Deactivation was also extremely rapid, with a decay time constant of about 300 μs near -80 mV. These rapid activation and deactivation kinetics are consistent with mediation by Kv3-family channels but are even faster than reported for Kv3-family channels in other neurons. The peptide toxin BDS-I had very little blocking effect on potassium currents elicited by 100-ms depolarizing steps, but the potassium ...
TY - JOUR. T1 - The energetic state within hibernating myocardium is normal during dobutamine despite inhibition of ATP-dependent potassium channel opening with glibenclamide. AU - McFalls, Edward O.. AU - Kelly, Rosemary F.. AU - Hu, Qingsong. AU - Mansoor, Abdul. AU - Lee, Joseph. AU - Kuskowski, Michael. AU - Sikora, Joseph. AU - Ward, Herbert B.. AU - Zhang, Jianyi. PY - 2007/11. Y1 - 2007/11. N2 - Within hibernating myocardium, it is uncertain whether a normal energetic state is present at baseline and whether maintaining that energy state during a catecholamine challenge is dependent on ATP-dependent potassium channel opening. In this study, 16 swine underwent a thoracotomy with placement of an external constrictor on the left anterior descending coronary artery (LAD) (hibernation model). Seven additional swine underwent a sham operation. At 10 wk, the myocardial energetic state in the LAD region was assessed by 31P-NMR spectroscopy, and the ratio of phosphocreatine to ATP (PCr/ATP) was ...
Potassium voltage-gated channel subfamily D member 2 is a protein that in humans is encoded by the KCND2 gene. It contributes to the cardiac transient outward potassium current (Ito1), the main contributing current to the repolarizing phase 1 of the cardiac action potential. Voltage-gated potassium (Kv) channels represent the most complex class of voltage-gated ion channels from both functional and structural standpoints. Their diverse functions include regulating neurotransmitter release, heart rate, insulin secretion, neuronal excitability, epithelial electrolyte transport, smooth muscle contraction, and cell volume. Four sequence-related potassium channel genes - shaker, shaw, shab, and shal - have been identified in Drosophila, and each has been shown to have human homolog(s). This gene encodes a member of the potassium channel, voltage-gated, shal-related subfamily, members of which form voltage-activated A-type potassium ion channels and are prominent in the repolarization phase of the ...
Potassium channels are present in most mammalian cells, where they participate in a wide range of physiologic responses. The protein encoded by this gene is an integral membrane protein and inward-rectifier type potassium channel. The encoded protein has a greater tendency to allow potassium to flow into a cell rather than out of a cell. Eight transcript variants encoding the same protein have been found for this gene. [provided by RefSeq, Feb 2013 ...
In a previous study we reported the presence of a large conductance K+ channel in the membrane of endoplasmic reticulum (ER) from rat hepatocytes. The channel open probability (Po) appeared voltage dependent and reached to a minimum 0.2 at +50 mV. Channel activity in this case was found to be totally inhibited at ATP concentration 2.5 mM, glibenclamide 100 μM and tolbutamide 400 μM. Existing evidence indicates an impairment of endoplasmic reticulum functions in ER stress condition. Because ER potassium channels have been involved in several ER functions including cytoprotection, apoptosis and calcium homeostasis, a study was carried out to consider whether the ER potassium channel function is altered in a high fat diet model of ER stress. Male Wistar rats were made ER stress for 2 weeks with a high fat diet. Ion channel incorporation of ER stress model into the bilayer lipid membrane allowed the characterization of K+ channel. Our results indicate that the channel Po was significantly ...
Fig. 1 Reduction of functional TRESK channels in DRG neurons and its association with pain in bone lesion-bearing rats.. (A and B) TRESK immunofluorescence staining in ipsilateral L4/5 DRG neurons from naïve, phosphate-buffered saline (PBS)-injected, or bone-localized MRMT-1 tumor-bearing rats. Representative images (A) and a summary for the mean fluorescence intensity of TRESK immunostaining (B) are shown. n = 224 to 230 cells (from six rats) per time point per group. Two-way analysis of variance (ANOVA) followed by Bonferroni post hoc test: F3,1818 = 116.2, ***P , 0.001. (C and D) TRESK protein (C) and mRNA (D) abundance in the cells described in (A). n = 6 to 7 rats per time point per group. Two-way ANOVA followed by either Bonferroni post hoc test, F3,40 = 4.21 (C), or one-way ANOVA followed by Tukey post hoc test, F2,16 = 20.54 (D), ***P , 0.001. N, naïve; P, PBS; M, MRMT-1. (E and F) Representative TRESK current traces and a summary for the current density of both the total background ...
TY - JOUR. T1 - Up-regulation of A-type potassium currents protects neurons against cerebral ischemia. AU - Deng, Ping. AU - Pang, Zhi Ping. AU - Lei, Zhigang. AU - Shikano, Sojin. AU - Xiong, Qiaojie. AU - Harvey, Brandon K.. AU - London, Barry. AU - Wang, Yun. AU - Li, Min. AU - Xu, Zao C.. PY - 2011/9/1. Y1 - 2011/9/1. N2 - Excitotoxicity is the major cause of many neurologic disorders including stroke. Potassium currents modulate neuronal excitability and therefore influence the pathological process. A-type potassium current (IA) is one of the major voltage-dependent potassium currents, yet its roles in excitotoxic cell death are not well understood. We report that, following ischemic insults, the IA increases significantly in large aspiny (LA) neurons but not medium spiny (MS) neurons in the striatum, which correlates with the higher resistance of LA neurons to ischemia. Activation of protein kinase Cα increases IA in LA neurons after ischemia. Cultured neurons from transgenic mice lacking ...
Cerebellar granule neurons (CGNs) are one of the most populous cells in the mammalian brain. They express an outwardly rectifying potassium current, termed a
Recent cloning of a family of genes encoding inwardly rectifying K+ channels has provided the opportunity to explain some venerable problems in membrane biology. An expanding number of novel inwardly rectifying K+ channel clones has revealed multiple channel subfamilies that have specialized roles i …
Read Kinetic Analysis of the Inhibitory Effect of Glibenclamide on KATP Channels of Mammalian Skeletal Muscle, The Journal of Membrane Biology on DeepDyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips.
The anti-contractile effect of perivascular adipose tissue (PVAT) is an important mechanism in the modulation of vascular tone in peripheral arteries. Recent evidence has implicated the XE991-sensitive voltage-gated Kv (KCNQ) channels in the regulation of arterial tone by PVAT. However, until now the in vivo pharmacology of the involved vascular Kv channels with regard to XE991 remains undetermined, since XE991 effects may involve Ca2+ activated BKCa channels and/or voltage-dependent Kv1.5 channels sensitive to diphenyl phosphine oxide-1 (DPO-1). In this study, we tested whether Kv1.5 channels are involved in the control of mesenteric arterial tone and its regulation by PVAT. Our study was also aimed at extending our current knowledge on the in situ vascular pharmacology of DPO-1 and XE991 regarding Kv1.5 and BKCa channels, in helping to identify the nature of K+ channels that could contribute to PVAT-mediated relaxation. XE991 at 30 µM reduced the anti-contractile response of PVAT, but had no effects
Potassium channels represent the most complex class of voltage-gated ion channels from both functional and structural standpoints. Their diverse functions include regulating neurotransmitter release, heart rate, insulin secretion, neuronal excitability, epithelial electrolyte transport, smooth muscle contraction, and cell volume. Four sequence-related potassium channel genes - shaker, shaw, shab, and shal - have been identified in Drosophila, and each has been shown to have human homolog(s). This gene encodes a member of the potassium channel, voltage-gated, shaker-related subfamily. This member contains six membrane-spanning domains with a shaker-type repeat in the fourth segment. It belongs to the delayed rectifier class, members of which allow nerve cells to efficiently repolarize following an action potential. It plays an essential role in T-cell proliferation and activation. This gene appears to be intronless and it is clustered together with KCNA2 and KCNA10 genes on chromosome 1.
Yılanı / dilatör yanıtları (basınç kasılmaların kâğıda çizilmesi kullanarak) ölçümleri ile paralel izole arteriyel miyositler (yama...
K11085 msbA; ATP-binding cassette, subfamily B, bacterial MsbA [EC:3.6.3.-] K11085 msbA; ATP-binding cassette, subfamily B, bacterial MsbA [EC:3.6.3.-] K06147 ABCB-BAC; ATP-binding cassette, subfamily B, bacterial K06147 ABCB-BAC; ATP-binding cassette, subfamily B, bacterial K06147 ABCB-BAC; ATP-binding cassette, subfamily B, bacterial K06147 ABCB-BAC; ATP-binding cassette, subfamily B, bacterial K06147 ABCB-BAC; ATP-binding cassette, subfamily B, bacterial K06147 ABCB-BAC; ATP-binding cassette, subfamily B, bacterial K06147 ABCB-BAC; ATP-binding cassette, subfamily B, bacterial K06147 ABCB-BAC; ATP-binding cassette, subfamily B, bacterial K06160 pvdE; putative pyoverdin transport system ATP-binding/permease protein K15738 uup; ABC transport system ATP-binding/permease protein K21397 K21397; ABC transport system ATP-binding/permease protein K21397 K21397; ABC transport system ATP-binding/permease protein K23163 sbp; sulfate/thiosulfate transport system substrate-binding protein K02046 cysU; ...
Potassium Channels Inhibitors on signaling pathway are available at Adooq Bioscience. Check Potassium Channels pathway , inhibitors reviews and assay information.
In this recent study the researchers discovered a change in a potassium channel that is a major cause of secondary hypertension. Remember that normally an increase in aldosterone leads to an increase in sodium reabsorption in the kidney and a rise in blood pressure. Normally when there is an increase in potassium outside the cell, potassium will move into the cell.. In certain adrenal gland cells the resulting increase in membrane polarization (the difference in electrical charges across the membrane) leads to less aldosterone secretion. The lowering of aldosterone leads to less sodium reabsorption in the kidney, and thus lower blood pressure. In some people blood pressure is high and does not come down, because they have a gene that prevents this normal sequence.. In this particular study, a gene variant was found that affected part of a potassium channel. The change meant that the channel no longer allowed only potassium to pass. The channel allowed sodium to pass through the potassium channel ...
A compound of formula (I) wherein A, X, Y, Z, R.sub.1 and R.sub.24 are described herein. The compounds are useful as inhibitors of potassium channel function and in the treatment and prevention of arrhythmia, I.sub.Kur-associated disorders, and other disorders mediated by ion channel function. ##STR00001##
History Early advancement of cardiac hypertrophy may be beneficial but suffered hypertrophic activation leads to myocardial dysfunction. the delayed outward rectifier potassium current (IK) and the instantaneous inward rectifier potassium current (IK1) and Akt activity respectively. Results Hypertrophied cardiomyocytes showed reduction in IK and IK1. Treatment with captopril alleviated this JTP-74057 difference seen between JTP-74057 sham and shunt cardiomyocytes. Acute administration of ANG II (10?6M) to cardiocytes treated with captopril reduced IK and IK1 in shunts but not in sham. Captopril treatment reversed SPP1 ANG II effects on IK and IK1 in a PI3-K-independent manner. However in the absence of angiotensin transforming enzyme inhibition ANG II increased both IK and IK1 in a PI3-K-dependent manner in hypertrophied cardiomyocytes. Conclusions Thus captopril treatment reveals a negative effect of ANG II on IK and IK1 which is usually PI3-K impartial whereas in the absence of angiotensin ...
Vernakalant Hcl(RSD-1235) is an investigational mixed ion channel blocker that can terminate acute atrial fibrillation (AF) in humans at 2 to 5 mg/kg and may be more atrial-selective than available agents; in treatment of antiarrhythmic ...
The protein encoded by this gene forms a potassium channel that is thought to play a critical role in the regulation of neuronal excitability, particularly in sensory cells of the cochlea. The current generated by this channel is inhibited by M1 muscarinic acetylcholine receptors and activated by retigabine, a novel anti-convulsant drug. The encoded protein can form a homomultimeric potassium channel or possibly a heteromultimeric channel in association with the protein encoded by the KCNQ3 gene. Defects in this gene are a cause of nonsyndromic sensorineural deafness type 2 (DFNA2), an autosomal dominant form of progressive hearing loss. Two transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2008 ...
Endogenous voltage-gated potassium currents were investigated in human embryonic kidney (HEK293) and Chinese hamster ovary (CHO) cells using whole-cell voltage clamp recording. Depolarizing voltage steps from -70 mV triggered an outwardly rectified current in nontransfected HEK293 cells. This current had an amplitude of 296 pA at +40 mV and a current density of 19.2 pA/pF. The outward current was eliminated by replacing internal K+ with Cs+ and suppressed by the K+ channel blockers tetraethylammonium and 4-aminopyridine. Raising external K+ attenuated the outward current and shifted the reversal potential towards positive potentials as predicted by the Nernst equation. The current had a fast activation phase but inactivated slowly. These features implicate delayed rectifier (I(K))-like channels as mediators of the observed current, which was comparable in size to I(K) currents in many other cells. A small native inward rectifier current but no transient outward current I(A), the M current I(M), ...
Planar silicon chips with 1-2-μm etched holes (average resistance: 2.04 ± 0.02 MΩ in physiological buffer, n = 274) have been developed for patch-clamp recordings of whole-cell currents from cells in suspension. An automated 16-channel parallel screening system, QPatch 16, has been developed using this technology. A single-channel prototype of the QPatch system was used for validation of the patch-clamp chip technology. We present here data on the quality of patch-clamp recordings and from actual drug screening studies of human potassium channels expressed in cultured cell lines. Using Chinese hamster ovary (CHO) and human embryonic kidney cells (HEK), gigaseals of 4.1 ± 0.4 GΩ (n = 146) and high-quality whole-cell current recordings were obtained from hERG and KCNQ4 potassium channels. Success rates for gigaseal recordings varied from 40 to 95%, and 67% of the whole-cell configurations lasted for ,20 min. Cells were maintained in suspension up to 4 h in a cell storage facility that is ...
Planar silicon chips with 1-2-μm etched holes (average resistance: 2.04 ± 0.02 MΩ in physiological buffer, n = 274) have been developed for patch-clamp recordings of whole-cell currents from cells in suspension. An automated 16-channel parallel screening system, QPatch 16, has been developed using this technology. A single-channel prototype of the QPatch system was used for validation of the patch-clamp chip technology. We present here data on the quality of patch-clamp recordings and from actual drug screening studies of human potassium channels expressed in cultured cell lines. Using Chinese hamster ovary (CHO) and human embryonic kidney cells (HEK), gigaseals of 4.1 ± 0.4 GΩ (n = 146) and high-quality whole-cell current recordings were obtained from hERG and KCNQ4 potassium channels. Success rates for gigaseal recordings varied from 40 to 95%, and 67% of the whole-cell configurations lasted for ,20 min. Cells were maintained in suspension up to 4 h in a cell storage facility that is ...
InterPro provides functional analysis of proteins by classifying them into families and predicting domains and important sites. We combine protein signatures from a number of member databases into a single searchable resource, capitalising on their individual strengths to produce a powerful integrated database and diagnostic tool.
The study which was led by Winthrop Professor David Hunt from UWAs Neuroecology Group and Lions Eye Institute, and included researchers from University College London, was published recently in the international Journal of Biological Chemistry.. Professor Hunt and his colleagues examined the genetic origins of a blinding disorder, in which symptoms include a loss of central vision and visual acuity, progressing on to a severe impairment of vision.. Earlier research found the disorder was caused by mutations in the gene that encodes a particular potassium channel protein, and Professor Hunt and his team looked at the effects of mutant channel proteins on the overall function of potassium channels.. Potassium channels are found throughout most living organisms and generate electrical signals. In the eye, the channels affect the function of cone and rod photoreceptors and the presence of mutant forms of channel proteins can be diagnosed quite specifically by a patients particular reaction to ...
The actions of the opioid agonist U50488H on I-A and I-K were examined in acutely isolated mouse hippocampal CA3 pyramidal neurons using the whole-cell patch clamp technique. U50488H caused a concentration dependent, rapidly developing and reversible inhibition of voltage-activated I-A and I-K. The inhibitory actions were still observed in the presence of 30 muM naloxone or 5 muM nor-binaltorphimine dihydrochloride. The IC50 values for the blockade of I-A and I-K were calculated as 20.1.9 and 3.7 muM, respectively. In the presence of 3.3 muM U50488H, repetitive stimulation induced use-dependent inhibition of I-A and I-K. A 10 muM concentration of U50488H positively shifted the half-activation membrane potential of I-A by +11 mV, but negatively shifted I-K by -14 mV. These results demonstrate that U50488H can directly inhibit neuronal I-A and I-K without involvement of the activation of kappa -opioid receptors. (C) 2001 Elsevier Science B.V. All rights ...
The Kvβ subunit of voltage-dependent potassium (Kv) channels has structural similarity to aldo-keto reductases (AKRs), enzymes that catalyze reduction of aldehyde groups to alcohols that are coupled to oxidation of an NADPH cofactor. However, it was unclear whether the Kvβ protein functioned in a catalytic capacity in its interaction with Kv channels, which allow voltage-sensitive conductance of potassium ions that is critical for action potentials in excitable cells. Weng et al. used spectrophotometric assays to show that purified rat Kvβ2 had associated NADPH and could reduce small-molecule aldehydes known to serve as substrates for other AKRs. Under other conditions, Kvβ2 could promote the reverse reaction--transfer of a hydride from an alcohol to reduce NADP+. Mutation of residues in the active site of the enzyme diminished the enzymatic activity. Application of a Kvβ substrate to Kv channels in inside-out patches from oocytes expressing the channel subunits decreased channel ...
Two-pore potassium channels (K2Ps) activation[edit]. *Two-pore potassium channels (K2Ps) modulate the potassium conductance ... This drug-elicited channel activation has been shown to be dependent upon specific amino-acids within certain K2P channels (i.e ... The K2P channel family comprises six subfamilies, which includes 15 unique members. 13 of these channels (excluding TWIK-1 and ... Opening of these channels therefore facilitates a hyperpolarizing current, which reduces neuronal excitability. K2Ps have been ...
gap junction channel activity. Cellular component. • cytoplasm. • integral component of membrane. • gap junction. • cell ... Connexins are membrane-spanning proteins that assemble to form gap junction channels that facilitate the transfer of ions and ... Typically the GJB1 protein forms channels through the myelin to the internal Schwann cell or oligodendrocyte, allowing ...
... potassium-channel. Potassium Channel. 1 August 2017. Retrieved 18 September 2017. "SH2D3A Gene". genecards.org. Gene Cards. ...
When a Gβγ or Gα(GTP) molecule binds to the C-terminus of the potassium channel, it becomes active, and potassium ions are ... The activation of the potassium channel and subsequent deactivation of the calcium channel causes membrane hyperpolarization. ... Yamada M, Inanobe A, Kurachi Y (December 1998). "G protein regulation of potassium ion channels". Pharmacological Reviews. 50 ( ... Embedded in the cell membrane is also the G protein-coupled inwardly-rectifying potassium channel. ...
Potassium channel (Kv7) opener.[116]. PO, rectal.. Bioavailability = 90% (oral), 72.5% (rectal); protein binding = 80%; volume ... Comes in potassium and free acid forms; degrades upon contact with light. Propionic acid derivative.. As per diclofenac.. PO.. ... N-type calcium-channel blocker.. Intrathecal.. Protein binding = 50%; half-life = 2.9-6.5 hours; excretion = urine (,1%).[122] ... Flupirtine is a centrally acting K+ channel opener with weak NMDA antagonist properties.[34] It is used in Europe for moderate ...
More specifically, SUR proteins are subunits of the inward-rectifier potassium ion channels Kir6.x (6.1 and 6.2). The ... Hence, the KATP channel monitors the energy balance within the cell. Depending on the tissue in which the KATP channel is ... Campbell JD, Sansom MS, Ashcroft FM (November 2003). "Potassium channel regulation". EMBO Reports. 4 (11): 1038-42. doi:10.1038 ... "ATP-dependent potassium channel blockade strengthens microglial neuroprotection after hypoxia-ischemia in rats". Experimental ...
Doxapram blocks leak potassium channels in the Tandom pore domain family of potassium channels while GAL-021 blocks BK channels ... Two common potassium channel blockers are Doxapram and GAL-021. Both act on potassium channels in Carotid Bodies. These cells ... Blocking the potassium channels on the membranes of these cells effectively depolarizes the membrane potential, which in turn ... Analeptics can act as potassium channel blockers, ampakines, and serotonin receptor agonists, and adenosine antagonism. ...
August 2005). "The voltage-gated potassium channel Kv1.3 is highly expressed on inflammatory infiltrates in multiple sclerosis ... Beeton C, Chandy KG (December 2005). "Potassium channels, memory T cells, and multiple sclerosis". Neuroscientist. 11 (6): 550- ... June 2003). "The voltage-gated Kv1.3 K(+) channel in effector memory T cells as new target for MS". J. Clin. Invest. 111 (11): ...
Potassium channels demonstrate a seemingly counterintuitive activity: they permit the passage of potassium ions, whereas they ... These channels are of particular importance to the nervous system and the heart and enable potassium ions to cross the cell ... In 1989 he was appointed assistant professor at Harvard University where he studied the interaction of the potassium channel ... Before MacKinnon's work, the detailed molecular architecture of potassium channels and the exact means by which they conduct ...
... s express potassium channels at a high density. When neurons are active, they release potassium, increasing the local ... Walz W (2000). "Role of astrocytes in the clearance of excess extracellular potassium". Neurochemistry International. 36 (4-5 ... Because astrocytes are highly permeable to potassium, they rapidly clear the excess accumulation in the extracellular space.[17 ... Abnormal accumulation of extracellular potassium is well known to result in epileptic neuronal activity.[18] ...
MiRP2 - β subunit to voltage-gated potassium channels. Modulates the transient outward potassium current Ito. [17] ... while others form different types of sodium channel (SCN10A). Some genes encode ion channels that carry calcium or potassium ... KVβ2, voltage-gated potassium channel β2 subunit - mutation increases Ito. [17] ... KV4.3, α-subunit of the transient outward potassium channel Ito.[6] ...
Nichol's research investigates the biology of ion channels, particularly potassium channels, and their role in diabetes ... CS1 maint: discouraged parameter (link) Nichols, C. G.; Lopatin, A. N. (1997). "Inward Rectifier Potassium Channels". Annual ... Nichols, C. G.; Lederer, W. J. (1991). "Adenosine triphosphate-sensitive potassium channels in the cardiovascular system". The ... Nomenclature and Molecular Relationships of Inwardly Rectifying Potassium Channels". Pharmacological Reviews. 57 (4): 509-26. ...
January 2020). "2+-activated potassium channels". Proceedings of the National Academy of Sciences of the United States of ... channels. It is thought that dopamine neuron survival and behavioral abnormalities are due to the over expression of LINGO-1 in ...
BmP05 acts blocks the Ca2+-activated K+ channel (SKCa), whereas BmP02 acts on potassium channels, but is not able to exert a ... Xu Y, Wu J, Pei J, Shi Y, Ji Y, Tong Q (November 2000). "Solution structure of BmP02, a new potassium channel blocker from the ... BmP02 targets potassium channels. Its activity has been shown in Kv1.1-Kv1.3, Kv4.2, Shaker-IR (Inactivation Removed) type, and ... The Kv 4.2 channel partially mediates the transient outward potassium current (Ito) in adult rat ventricular myocytes. Three ...
Potassium channel, subfamily K, member 7, also known as KCNK7 or K2P7.1 is a protein which is encoded in humans by the KCNK7 ... "Entrez Gene: potassium channel". Strausberg RL, Feingold EA, Grouse LH, et al. (2002). "Generation and initial analysis of more ... K2P7.1 is a potassium channel containing two pore-forming P domains. Multiple transcript variants encoding different isoforms ... This gene encodes a member of the superfamily of potassium channel proteins containing two pore-forming P domains. The product ...
K+ channels. HgTX1 shows high affinity with Kv1.1, Kv1.2, Kv1.3 voltage-gated potassium channels, but much lower affinity with ... Potassium channel inhibitor family. Alpha-KTx 2 subfamily. There are five subtypes known of the hongotoxin peptide. HgTX1 is 39 ... Hongotoxin (HgTX) is an ion channel toxin, which blocks Shaker-type (Kv1) K+ channels. The toxin is derived from the venom of ... HgTX4 and HgTX5 are potent selective inhibitors of Kv1 voltage-gated potassium channels (By similarity). ND, not determined. ...
... channel), voltage gated potassium channel HBK1, voltage gated potassium channel subunit Kv1.1, voltage-gated K+ channel HuKI ... potassium channel activity. • delayed rectifier potassium channel activity. • voltage-gated ion channel activity. • GO:0015388 ... Potassium voltage-gated channel subfamily A member 1 also known as Kv1.1 is a shaker related voltage-gated potassium channel ... "Entrez Gene: KCNA1 potassium voltage-gated channel".. *^ "KCNA1 - Potassium voltage-gated channel subfamily A member 1 - Homo ...
It binds to several subclasses of voltage-gated potassium channels (Kv channels), including Kv1.1, Kv1.6, and less potently to ... By blocking potassium channels, the MCD peptide can increase the duration of action potentials and increase neuronal ... This toxicity is caused by the blockage of voltage-gated potassium channels by the MCD peptide. However, there is no toxicity ... In addition, it is a potent blocker of voltage-sensitive potassium channels. MCD peptide is a component of bumblebee ( ...
Dreyer, Ingo; Uozumi, Nobuyuki (2011-11-01). "Potassium channels in plant cells". FEBS Journal. 278 (22): 4293-4303. doi: ... Since glucose is a large molecule, it requires a specific channel to facilitate its entry across plasma membranes and into ... transport of particular ions such as potassium down their charge gradient through high affinity transporters and channels. An ... Chen, Lihong; Tuo, Biguang; Dong, Hui (2016-01-14). "Regulation of Intestinal Glucose Absorption by Ion Channels and ...
Patil, N; Cox, D. R; Bhat, D; Faham, M; Myers, R. M; Peterson, A. S (1995). "A potassium channel mutation in weaver mice ... Bendahhou, S; Donaldson, M. R; Plaster, N. M; Tristani-Firouzi, M; Fu, Y. H; Ptácek, L. J (2003). "Defective potassium channel ... Huang, Xi; Jan, Lily Yeh (2014). "Targeting potassium channels in cancer". The Journal of Cell Biology. 206 (2): 151-62. doi: ... Morokuma, J; Blackiston, D; Adams, D. S; Seebohm, G; Trimmer, B; Levin, M (2008). "Modulation of potassium channel function ...
The site of action of TTX on the sodium channel has been identified. Dendrotoxins block the potassium channels. These drugs ... The transmembrane potential is restored by delayed opening of potassium channels. Soliton hypothesis proponents assert that ... Hodgkin AL, Huxley AF, Katz B (1952). "Currents carried by sodium and potassium ions through the membrane of the giant axon of ... The model is proposed as an alternative to the Hodgkin-Huxley model in which action potentials: voltage-gated ion channels in ...
"Potassium channel-based optogenetic silencing". Nature Communications. 9 (1): 4611. Bibcode:2018NatCo...9.4611B. doi:10.1038/ ... Recently, it has been shown that expression of PAC together with K+-specific cyclic-nucleotide-gated ion channels (CNGs) can be ... "Synthetic Light-Activated Ion Channels for Optogenetic Activation and Inhibition". Frontiers in Neuroscience. 12: 643. doi: ...
... the inward potassium rectifier current (IKI), the ATP-sensitive potassium channel (IKATP) and Ito. At micromolar concentrations ... Quinidine also blocks certain voltage-gated potassium channels (e.g., Kv1.4, Kv4.2, hERG, among others), acts as an ... 303-. ISBN 978-3-527-67367-4. Stephen L. Archer; Nancy J. Rusch (6 December 2012). Potassium Channels in Cardiovascular Biology ... Quinidine acts as a blocker of voltage-gated sodium channels. Inhibition of the Nav1.5 channel is specifically involved in its ...
κ-conotoxin inhibits potassium channels. μ-conotoxin inhibits voltage-dependent sodium channels in muscles. ω-conotoxin ... whereas delta conotoxins delay the inactivation of sodium channels, and kappa conotoxins are potassium channel blockers. Mu- ... Different subtypes of voltage-gated sodium channels are found in different tissues in mammals, e.g., in muscle and brain, and ... However, it appears that many of these peptides modulate the activity of ion channels. Over the last few decades conotoxins ...
By blocking specifically the Kv4 channels, AmmTX3 reduces the A-type potassium current through these channels almost completely ... A-type potassium currents can be generated by Kv1.4, Kv3.3, Kv3.4, all members of Kv4 and Erg3 channels. The influence of ... The toxin is known for its ability to act as a specific Kv4 channel blocker, and thereby reducing the A-type potassium current ... Bougis, PE; Martin-Eauclaire, MF (25 June 2015). "Shal-type (Kv4.x) potassium channel pore blockers from scorpion venoms". ...
... is a potassium channel opener. Puddu, Paolo Emilio; Garlid, Keith D; Monti, Francesco; Iwashiro, Katsunori; Picard, ... A Promising KATP Channel Activating Agent". Cardiovascular Drug Reviews. 18: 25. doi:10.1111/j.1527-3466.2000.tb00031.x. v t e ...
... is a potassium channel blocker. Paxilline is a toxic, tremorgenic indole alkaloid produced by Penicillium paxilli . ... Sheehan, JJ; Benedetti, BL; Barth, AL (2009). "Anticonvulsant effects of the BK-channel antagonist paxilline". Epilepsia. 50: ... "Induction of seizures by the potent K+ channel-blocking scorpion venom peptide toxins tityustoxin-K(alpha) and pandinustoxin-K( ...
It blocks two potassium channel subtypes; voltage-gated and calcium-activated channels. Coba is a region in Mexico where the ... Other voltage-dependent K+-channels that are blocked by Cobatoxin 1 are the Kv1.2 K+-channels in rats and Kv1.3 K+-channels in ... Cobatoxin 1 and 2 both block the Kv1.1 K+-channels in mice and the Shaker B K+ channels in insects, which are voltage-dependent ... "Cobatoxins 1 and 2 from Centruroides noxius Hoffmann constitute a subfamily of potassium-channel-blocking scorpion toxins". Eur ...
... potassium channel. hERG contributes to the formation of potassium ion channel proteins that are responsible for the conduction ... In vitro studies have shown that this combined-ion channel blocker inhibits rapidly the activating delayed-rectifier potassium ... Sanguinetti, Michael C.; Tristani-Firouzi, Martin (2006). "HERG potassium channels and cardiac arrhythmia". Nature. 440 (7083 ... "Assessment of the Ion Channel-blocking Profile of the Novel Combined Ion Channel Blocker AZD1305 and Its Proarrhythmic ...
Kaczorowski, GJ; Knaus, HG; Leonard, RJ; McManus, OB; Garcia, ML (1996). "High-conductance calcium-activated potassium channels ... IPA acts on the large-conductance calcium activated K+ channels (BK channels). BK channels are formed by α subunits and ... or voltage sensitivity of the α subunit of BK channels without affecting the channel conductance. In this state BK channels can ... Isopimaric acid (IPA) is a toxin which acts as a large conductance Ca2+-activated K+ channel (BK channel) opener. IPA ...
Voltage sensitive ion channels are glycoprotein molecules which extend through the lipid bilayer, allowing ions to traverse ... under certain conditions through the axolemma), the fast-acting sodium and the inward-rectifying potassium. Though successful ...
Other potassium channels like large conductance calcium-dependent potassium channels and sodium chloride dependent potassium ... Moreover, ATP-dependent potassium channels help neurons detect changes in energy or oxygen levels to modify breathing patterns ... The channels are regulated by G protein-coupled receptors that can activate or inhibit the NALCN channels depending on the ... Although the exact role of potassium currents is still being investigated, it appears that potassium and sodium leak currents ...
ion channel activity. • benzodiazepine receptor activity. • chloride channel activity. • extracellular ligand-gated ion channel ... Bromide compounds (e.g., potassium bromide). *Carbamates (e.g., meprobamate). *Carbamazepine. *Chloralose ... inhibitory extracellular ligand-gated ion channel activity. • GABA-gated chloride ion channel activity. • transmitter-gated ion ... chloride channel complex. • cell junction. • plasma membrane. • GABA-ergic synapse. • integral component of postsynaptic ...
... which opens ion channels (largely sodium channels, though calcium can enter through these channels as well). The positive ... The chief function of the inner segment is to provide ATP (energy) for the sodium-potassium pump. Finally, closest to the brain ... ATP provided by the inner segment powers the sodium-potassium pump. This pump is necessary to reset the initial state of the ... Thus, the random opening or closing of sodium channels will not affect the membrane potential of the cell; only the closing of ...
The eggs hatch in about 2 weeks, and the tiny larvae tunnel to the wood and score its surface with their feeding channels. With ... 1. The influence of nitrogen, phosphorus, potassium and magnesium deficiencies on the growth and development of white spruce, ... potassium, calcium, magnesium, and sulfur, all used in relatively large amounts (Buckman and Brady 1969).[31] Nutrient ... when larvae occasionally return to the surface of the wood and extend the feeding channels generally in a U-shaped ...
Hellgren, Mikko; Sandberg, Lars; Edholm, Olle (2006). "A comparison between two prokaryotic potassium channels (KirBac1.1 and ... potassium chloride).[30] Previously, potassium was generally made from the electrolysis of potassium chloride or potassium ... Potassium forms a mixture of potassium peroxide and potassium superoxide, while rubidium and caesium form the superoxide ... Potassium nitrate and potassium permanganate are often used as powerful oxidising agents.[10]:73 Potassium superoxide is used ...
Purified potassium nitrate: Ahli kimia Muslim adalah pertama untuk purify potassium nitrate (saltpetre; natrun atau barud dalam ... Ancient Discoveries]], Episode 12: Machines of the East, History Channel, dicapai 2008-09-08. Konflik URL-wikilink (bantuan) ... Potassium nitrate, pure: Dipisahkan oleh Hasan al-Ramah pada 1270an.[8]. Bahan kimia direka untuk kegunaan dalam industri kimia ... Ancient Discoveries]], Episode 12: Machines of the East, History Channel, dicapai 2008-09-07. Konflik URL-wikilink (bantuan) ...
But if the γ2 is expressed with α1 and β2 the sensitivity is low and channel conductance is high.[7] γ2 subunit has to be ... Bromide compounds (e.g., lithium bromide, potassium bromide, sodium bromide). *Carbamazepine. *Chloralose ... Upon binding, it triggers the GABAA receptor to open its chloride channel to allow chloride ions into the neuron, making the ... The channel conductance is not higher in the presence of benzodiazepine and GABA than the conductance with the presence of only ...
Other bases such as potassium carbonate or cesium carbonate are occasionally used. In addition, deaerated conditions are ... "A Practical and Efficient Synthesis of the Selective Neuronal Acetylcholine-Gated Ion Channel Agonist (S)-(−)-5-Ethynyl-3-(1- ...
"Mitochondrial Ion Channels: Gatekeepers of Life and Death". Physiology. 20 (5): 303-315. doi:10.1152/physiol.00020.2005. ISSN ...
鉀離子通道阻滯劑(英語:Potassium channel blocker) (PCB) ... 鉀離子通道開放劑(英語:Potassium channel opener) (PCO) ... 鈉離子通道阻滯劑(
States in which ginger is exported follow the marketing channels of vegetable marketing in India, and the steps are similar to ... water channels are made 60-80 ft apart to irrigate the crop.[29] ... See also: Receptor/signaling modulators • Ion channel ...
calcium channel activity. • metal ion binding. • voltage-gated ion channel activity. • ion channel activity. • protein binding ... voltage-gated calcium channel activity involved in cardiac muscle cell action potential. • high voltage-gated calcium channel ... When calcium ions bind to calmodulin, which in turn binds to a Cav1.2 channel, it allows the Cav1.2 channels within a cluster ... This gene encodes an alpha-1 subunit of a voltage-dependent calcium channel. Calcium channels mediate the influx of calcium ...
Similar agents are eplerenone and potassium canreonate.. *Epithelial sodium channel blockers: amiloride and triamterene. ... Potassium-sparing diuretics amiloride, spironolactone, eplerenone, triamterene, potassium canrenoate. Inhibition of Na+/K+ ... Potassium-sparing diureticsEdit. These are diuretics which do not promote the secretion of potassium into the urine; thus, ... potassium is retained and not lost as much as with other diuretics. The term "potassium-sparing" refers to an effect rather ...
... shows promise as an immunosuppressant by inhibiting a specific potassium channel. Its structure prevents intercalation into DNA ... Potassium permanganate causes oxidation of the furan ring, while other methods of oxidation produce furan-2,3-carboxylic acid. ... While cell-surface modification and ion channel blocking are two newly discovered mechanisms of action, much research remains ...
... but today is restricted to water channels in sponges[9] and the hydrostatic skeleton of some mollusks like Polinices.[10] ... the fluid also contains some protein and high levels of potassium salts.[11]:933-939 ...
The hand-sized square piece of metal contains microscopic channels with catalytic sites, which continuously convert biodiesel, ... it was found that though the presence of sodium and potassium carbonates aided in the catalytic conversion of ash, as the ... catalysts such as potassium hydroxide. However, the super-critical methanol production methodology, whereby the ...
SK2 potassium channels mediate inhibitory influence on action potentials and reduce arborization. ...
Ji, Jianguo; Bunnelle, William H.; Anderson, David J.; Faltynek, Connie; Dyhring, Tino; Ahring, Philip K.; Rueter, Lynne E.; Curzon, Peter; Buckley, Michael J.; Marsh, Kennan C.; Kempf-Grote, Anita; Meyer, Michael D. (2007). "A-366833: A novel nicotinonitrile-substituted 3,6-diazabicyclo[3.2.0]-heptane α4β2 nicotinic acetylcholine receptor selective agonist: Synthesis, analgesic efficacy and tolerability profile in animal models". Biochemical Pharmacology. 74 (8): 1253-1262. doi:10.1016/j.bcp.2007.08.010. PMID 17854775 ...
L-Type calcium channel blockers (e.g., dihydropyridines: nifedipine). *Nebivolol (beta blocker) ...
... or epithelial sodium channel blockers such as amiloride can be used to decrease urinary wasting of potassium.[1] ... channel (ClC-Kb), and the Na+/K+-ATPase. Indicated also are the recently identified magnesium channel TRPM6 in the apical ... Severe deficits of potassium and magnesium require intravenous replacement. If low blood potassium levels are not sufficiently ... Potassium and magnesium supplementation to normalize low blood levels of potassium and magnesium is the mainstay of treatment.[ ...
Varying amounts of potassium, sodium, phosphorus, calcium, magnesium, iron, and zinc were present.[81] ... Visual neuron of the locust, Ri Channel video, October 2011. *FAO Locust Watch ...
DDE concentration and percent eggshell thinning in Double-crested Conmorant eggs(North Channel, Lake Huron, Ont.) ...
... toxicity is due to absorption into cells and production of nano-channels that obstruct vital ion channels that ferry potassium ... and 11-residue peptaibols from the fungus Trichoderma longibrachiatum are synergistic in forming Na+/K+-permeable channels and ...
The alkali feldspars are most commonly in a series between potassium-rich orthoclase and sodium-rich albite; in the case of ... They form in the presence of water at low temperatures and pressures, and have channels and voids in their structure. Zeolites ... An example of a transparent mineral is muscovite (potassium mica); some varieties are sufficiently clear to have been used for ... Halite, NaCl, is table salt; its potassium-bearing counterpart, sylvite, has a pronounced bitter taste. Sulfides have a ...
It has been suggested that EDHF is potassium ions (K+), as the activation of endothelial K-Ca+ channels causes an efflux of K+ ... Subsequently, it was suggested that EDHF is a sulfur signal that results in activation of K channels via sulfhydration of a ... ions in EDHF-mediated relaxation does not necessarily involve the activation Na+-K+-ATPase channels. It is more likely that K+ ... because it may have an inhibitory action on K+ channels, at least, in some vascular beds.[1] ...
Dynamic oligomeric conversions of the cytoplasmic RCK domains mediate MthK potassium channel activity. Proc. Natl. Acad. Sci. ... The membrane can then be analyzed on a patch clamp apparatus to determine the phenotype of the ion channels embedded in it. It ... Specially prepared giant spheroplasts of Gram-negative bacteria can be used to study the function of bacterial ion channels ... Santos, J. S., Lundby, A., Zazueta, C., and Montal, M. (2006) Molecular template for a voltage sensor in a novel K+ channel. I ...
Melting of metallic electrodes and their flowing through a carbon nanotube channel within a device» Adv. Mater. 25 (2013) 2693- ... High-yield synthesis of boron nitride nanoribbons via longitudinal splitting of boron nitride nanotubes by potassium vapor» ACS ...
... but could relate to actions of the drug on voltage-activated calcium channels. Lamotrigine blocks T-type calcium channels ... At high concentrations, it had no effect on spontaneous or potassium evoked amino acid release.[45] ... Ion channel blockers. *Anticonvulsants (e.g., gabapentin, pregabalin, carbamazepine, oxcarbazepine, lacosamide, lamotrigine) ... Lamotrigine is a member of the sodium channel blocking class of antiepileptic drugs.[60] This may suppress the release of ...
Inward-rectifier potassium channels (Kir, IRK) are a specific subset of potassium channels. To date, seven subfamilies have ... such as the delayed rectifier and A-type potassium channels. Those more "typical" potassium channels preferentially carry ... "Inwardly Recifying Potassium Channels". IUPHAR Database of Receptors and Ion Channels. International Union of Basic and ... Inward-rectifier potassium channel. From Wikipedia, the free encyclopedia. (Redirected from Inward-rectifier potassium ion ...
... channels with distinct biophysical and biochemical properties. Possibly, this diversity reflects the need to regulate and... ... Neurons express a large number of different voltage-gated potassium (Kv) ... Delmas P, Brown DA (2005) Pathways modulating neural KCNQ/M (Kv7) potassium channels. Nat Rev Neurosci 6:850-862 PubMedCrossRef ... Pongs O (1999) Voltage-gated potassium channels: from hyperexcitability to excitement. FEBS Lett 452:31-35 PubMedCrossRefGoogle ...
Mediation of Neuronal Apoptosis by Kv2.1-Encoded Potassium Channels Sumon Pal, Karen A. Hartnett, Jeanne M. Nerbonne, Edwin S. ... Heteromeric KV2/KV8.2 Channels Mediate Delayed Rectifier Potassium Currents in Primate Photoreceptors Jacqueline Gayet-Primo, ... Dysregulation of Kv3.4 Channels in Dorsal Root Ganglia Following Spinal Cord Injury David M. Ritter, Benjamin M. Zemel, Tamara ... Epilepsy-Associated KCNQ2 Channels Regulate Multiple Intrinsic Properties of Layer 2/3 Pyramidal Neurons Zachary Niday, ...
Potassium channels: structures, diseases, and modulators.. Tian C1, Zhu R, Zhu L, Qiu T, Cao Z, Kang T. ... Potassium channels participate in many critical biological functions and play important roles in a variety of diseases. In ... There is no doubt that all these studies on potassium channels as possible pharmaceutical targets will facilitate future ... both qualitative and quantitative approaches are utilized to analyze structural features of modulators of potassium channels. ...
Single channel studies have identified two types of calcium-activated potassium channel which can also be separated on ... It is now clear that BK channels underlie I(c) whereas SK channels underlie I(AHP). The identity of the channels underlying I( ... Channels underlying neuronal calcium-activated potassium currents.. Sah P1, Faber ES. ... In this review, we discuss the properties of the different types of calcium-activated potassium channels and the relationship ...
Mechanism of Voltage Gating in Potassium Channels. By Morten Ø. Jensen, Vishwanath Jogini, David W. Borhani, Abba E. Leffler, ... Mechanism of Voltage Gating in Potassium Channels. By Morten Ø. Jensen, Vishwanath Jogini, David W. Borhani, Abba E. Leffler, ... Using all-atom molecular dynamics simulations, we show how a voltage-gated potassium channel (KV) switches between activated ... We propose a mechanistic model for the sodium/potassium/calcium voltage-gated ion channel superfamily that reconciles ...
Voltage-gated potassium channel (IPR028325)*Potassium channel, voltage dependent, Kv (IPR003968)*Potassium channel, voltage ... GO:0005216 ion channel activity GO:0005249 voltage-gated potassium channel activity GO:0005515 protein binding ... GO:0006813 potassium ion transport GO:0051260 protein homooligomerization GO:0055085 transmembrane transport ...
This domain is found in a variety of potassium channel proteins, including the two membrane helix type ion channels found in ...
Further reports about: , 3D structure , Biozentrum , HCN potassium channels , electrical impulse , potassium channel , ... 3D structure »Biozentrum »HCN potassium channels »electrical impulse »potassium channel »signaling molecule ... These signal-driven potassium channels are also referred to as "pacemaker channels". They help to generate the rhythm of the ... Neurons transmit information with the help of special channels that allow the passage of potassium ions. Defective potassium ...
Ion channel impairing toxin. ›Voltage-gated potassium channel impairing toxin. ›Calcium-activated potassium channel impairing ... Protein which interferes with the function of potassium channels which are membrane proteins forming a channel in a biological ... membrane selectively permeable to potassium ions. They are found in various venoms from snakes, scorpions and spiders. ...
immunogen = a synthetic peptide corresponding to the C-terminus of human potassium channel Kv4.3 ...
Renal fibrosis is attenuated by targeted disruption of KCa3.1 potassium channels. Ivica Grgic, Eva Kiss, Brajesh P. Kaistha, ... 1997) A novel gene, hKCa4, encodes the calcium-activated potassium channel in human T lymphocytes. J Biol Chem 272:32723-32726. ... Renal fibrosis is attenuated by targeted disruption of KCa3.1 potassium channels Message Subject (Your Name) has sent you a ... 1996) Potassium channels, proliferation and G1 progression. J Membr Biol 154:91-107. ...
Modulation of Potassium Channels and Arrhythmogenesis. Modulation of K+ channels can have marked effects on the repolarization ... channels. The inward rectifier potassium channel (IK1) was activated by 200-ms test pulses to −100 mV from a holding potential ... Fig 4⇓ summarizes the mean suppressive effects of astemizole and terfenadine on the potassium channels IK, IK1, and Ito in both ... DeFelice LJ, Goolsby WN, Mazzanti M. Potassium channels and the repolarization of cardiac cells. Ann N Y Acad Sci. 1990;588:174 ...
The family of SLO channels apparently evolved from voltage-dependent potassium channels, but acquired a large conserved ... channels encoded by the Slo gene family are among the largest and most complex of the extended family of potassium channels. ... Large-Conductance Calcium-Activated Potassium Channels / genetics * Large-Conductance Calcium-Activated Potassium Channels / ... The family of SLO channels apparently evolved from voltage-dependent potassium channels, but acquired a large conserved ...
... potassium channels include High-throughput Screening for Small-molecule Modulators of Inward Rectifier Potassium Channels, ... Profiling Voltage-gated Potassium Channel mRNA Expression in Nigral Neurons using Single-cell RT-PCR Techniques, Optical ... Use of Label-free Optical Biosensors to Detect Modulation of Potassium Channels by G-protein Coupled Receptors, ... Exploring Arterial Smooth Muscle Kv7 Potassium Channel Function using Patch Clamp Electrophysiology and Pressure Myography, ...
Serotonin Receptor Heterogeneity and the Role of Potassium Channels in Neuronal Excitability. ... Serotonin Receptor Heterogeneity and the Role of Potassium Channels in Neuronal Excitability. In: Kito S., Segawa T., Olsen R.W ... channel activation. The mechanism of K+ channel closure is less clear as it is unaffected by PTX or activation of adenylate ... Pertussis toxin-insensitive G protein mediates substance P-induced inhibition of potassium channels in brain neurones, ...
Newly analyzed potassium channel turns out to be a chimeric complex that incorporates the best features of otherwise separately ... a potassium channel combines functions once thought to be invariably asunder. This channel, which is found in common bacteria, ... Potassium ions are attracted from the outside by the high-affinity and high-selective channel-like subunit (KdpA, green), ... Green: channel-like subunit KdpA. Brown: p-type ATPase subunit KdpB. Purple spheres: potassium ions. Pink densities: entrance ...
Potassium channel activator Attenuates salicylate-induced cochlear hearing loss potentially Ameliorating tinnitus. *Sun W ... In this study, we tested whether opening voltage-gated potassium channels using ICA-105665, a novel small molecule that opens ... Sun, W., Liu, J., Zhang, C., Zhou, N., Manohar, S., Miranda, J. A., … Salvi, R. J. (2015). Potassium channel activator ... Therefore, enhancing OHC potassium currents could potentially prevent salicylate-induced temporary hearing loss. ...
... voltage-gated K+ channels, ATP-sensitive K+ channels, Ca2+-activated K+ channels, etc.), and each type of potassium ion channel ... function and regulation of several types of potassium ion channels, focusing on the role of these channels not only in terms of ... Potassium Channels in Health and Disease. $95.00. Hiroaki Kume, M.D., Ph.D. (Editor). Kindai University Faculty of Medicine, ... influx through voltage-gated Ca2+ channels by closing the Ca2+ channel. Outward potassium ion currents activated upon ...
S. B. Long, E. B. Campbell, R. MacKinnon, Crystal structure of a mammalian voltage-dependent Shaker family K+ channel. Science ... R. F. Service, A new portrait puts potassium pore in a fresh light. Science 309, 867 (2005). [Abstract] [Full Text] ... Forming crystals of the larger, multisubunit eukaryotic K+ channels has been more challenging, but Long et al. (see the cover ... Voltage-gated K+ channels open in response to cell depolarization, reacting to the change in potential by movement of four ...
... voltage-gated potassium channels (KV), blocked by 4-AP [23], inward rectifying potassium channel (Kir), blocked by Ba2+ [24], ... Using a nonselective potassium channel blocker, the CsCl, the relaxant effect of p-cymene was attenuated. In the presence of ... calcium channels; the second mechanism involves change in membrane potential and activation of channels, with a subsequent Ca2+ ... The Vasorelaxant Effect of p-Cymene in Rat Aorta Involves Potassium Channels. Martapolyana T. M. Silva,1 Fernanda P. R. A. ...
4.1.2. Inwardly Rectifying Potassium (Kir) Channels in SAH. Next to channels, expression of an inwardly rectifying potassium ... 4.1.4. ATP-Dependent (KATP) Potassium Channels in SAH. An important role of KATP channels in animal models of SAH-induced ... 2. Ion Channels Healthy Cerebral Vessels. 2.1. Expression and Function of Potassium Channels in Healthy Cerebral Vessels. ... M. T. Nelson, J. B. Patlak, J. F. Worley, and N. B. Standen, "Calcium channels, potassium channels, and voltage dependence of ...
2009) Coupling of activation and inactivation gate in a K+-channel: Potassium and ligand sensitivity. EMBO J 28(18):2825-2834. ... 2008) Solid-state NMR spectroscopy applied to a chimeric potassium channel in lipid bilayers. J Am Chem Soc 130(23):7427-7435. ... 2007) Solid-state NMR study and assignments of the KcsA potassium ion channel of S. lividans. Biochim Biophys Acta 1774(12): ... 2006) Two-dimensional solid-state NMR applied to a chimeric potassium channel. J Recept Signal Transduct Res 26(5-6):379-393. ...
Potassium Ion Channels. Some articles on potassium ion channels, potassium, ion, potassium ions, ions:. Orexin-A - Mechanism. ... Potassium Channel - Structure - Selectivity Filter. ... Potassium ion channels remove the hydration shell from the ion when it ... Tests show a class of potassium ion channels that are porelike proteins in the cell membrane and they affect the cellular ... responses by controlling the flow of potassium ... The exact mechanism of the potassium ion channels is unknown, but the ...
... channels. The crystal structure of KirBac1.1 and related KirBac3.1 have now been used extensively to generate in silico models ... of eukaryotic Kir channels, but functional analysis has been limited to (86)Rb(+) flux ex … ... KirBac1.1 is a prokaryotic homologue of eukaryotic inward rectifier potassium (Kir) ... KirBac1.1: its an inward rectifying potassium channel J Gen Physiol. 2009 Mar;133(3):295-305. doi: 10.1085/jgp.200810125. Epub ...
Inward-rectifier potassium channels (Kir, IRK) are a specific subset of potassium channels. To date, seven subfamilies have ... such as the delayed rectifier and A-type potassium channels. Those more "typical" potassium channels preferentially carry ... "Inwardly Recifying Potassium Channels". IUPHAR Database of Receptors and Ion Channels. International Union of Basic and ... These channels differ from the potassium channels that are typically responsible for repolarizing a cell following an action ...
The remaining current for KCNJ3/KCNJ5L168R may be a potassium current because it was blocked by the known potassium channel ... an effect that is reversible upon inhibition of the channel with the potassium channel blocker barium. Changes in membrane ... Potassium channel mutant KCNJ5 T158A expression in HAC-15 cells increases aldosterone synthesis. Endocrinology. 2012;153(4): ... Macrolides selectively inhibit mutant KCNJ5 potassium channels that cause aldosterone-producing adenoma. Ute I. Scholl,1,2 ...
... the authors identify differential requirements of two potassium channel proteins, Kv1.3 and KCa3.1, for the induction of ... Potassium channels are essential for modulating T-cell functions. Here, by characterizing rat models and analysing human T ... In addition, while our studies have focused on the K+ channels, other channel types such as store-operated Ca2+ entry channel ... The voltage-gated potassium channel Kv1.3 regulates energy homeostasis and body weight. . Hum. Mol. Genet. 12, 551-559 (2003). ...
WebMD provides information about interactions between Stavzor Oral and sodium-channel-blocker-potassium-channel-blocker- ... Lacosamide/Sodium Channel Blockers; Potassium Channel Blockers Interactions. This information is generalized and not intended ...
The present invention also provides novel compositions comprising at least one potassium channel activator, and at least one ... and novel compositions comprising at least one nitrosated and/or nitrosylated potassium channel activator, and, optionally, at ... The present invention describes novel nitrosated and/or nitrosylated potassium channel activators, ... Potassium channel activators have the ability to open potassium channels in a variety of cells. Opening of the potassium ...
  • High-level expression of cloned channels led to the discovery that classical inward so-called anomalous rectification is caused by voltage-dependent block of the channel by polyamines and Mg2+ ions, and it is now clear that a similar mechanism results in inward rectification of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA)-kainate receptor channels. (nih.gov)
  • At membrane potentials negative to potassium's reversal potential , inwardly rectifying K + channels support the flow of positively charged K + ions into the cell, pushing the membrane potential back to the resting potential. (wikipedia.org)
  • The phenomenon of inward rectification of K ir channels is the result of high-affinity block by endogenous polyamines , namely spermine , as well as magnesium ions, that plug the channel pore at positive potentials, resulting in a decrease in outward currents. (wikipedia.org)
  • These channels achieve the remarkable feat of fast, efficient transport of potassium ions, while rejecting sodium ions with high fidelity. (biophysics.org)
  • The image was constructed using a narrow depth of field to bring the potassium ions (purple) and water molecules in the central part of the channel into focus. (biophysics.org)
  • This central part of the channel, which is small enough to force potassium ions and water molecules into single file, is thought to be responsible for its selectivity and efficiency. (biophysics.org)
  • Yet, researchers still debate on how the movement of water molecules and potassium ions through the channel creates this selectivity. (biophysics.org)
  • Neurons transmit information with the help of special channels that allow the passage of potassium ions. (innovations-report.com)
  • They form a pore with a filter that selectively allows the passage of potassium ions, and which is controlled by the signaling molecule cAMP. (innovations-report.com)
  • It was previously assumed that the pore could open and close, thus regulating the flow of potassium ions. (innovations-report.com)
  • We think that cAMP in fact widens the filter somewhat, thereby controlling the flow of potassium ions. (innovations-report.com)
  • Protein which interferes with the function of potassium channels which are membrane proteins forming a channel in a biological membrane selectively permeable to potassium ions. (uniprot.org)
  • The family of SLO channels apparently evolved from voltage-dependent potassium channels, but acquired a large conserved carboxyl extension, which allows channel gating to be altered in response to the direct sensing of several different intracellular ions, and by other second-messenger systems, such as those activated following neurotransmitter binding to G-protein-coupled receptors (GPCRs). (nih.gov)
  • Potassium ions are attracted from the outside by the high-affinity and high-selective channel-like subunit (KdpA, green), redirected via an intermembrane tunnel to the P-type subunit (KdpB, in brown), and from there released to the cytoplasm. (genengnews.com)
  • In fact, the subunits work together, allowing bacteria to import potassium ions against extreme concentration gradients. (genengnews.com)
  • Purple spheres: potassium ions. (genengnews.com)
  • In this situation," explained Paulino, "where the concentration outside is so very low, you need extremely high affinity to bind the potassium ions, and the system needs to overcome a very high energy barrier to import the potassium ions. (genengnews.com)
  • Essentially, KdpFABC contains a set of tunnels that allow potassium ions to enter the channel from the outside, bridge to the transporter unit, and then pass through another tunnel into the cell. (genengnews.com)
  • The pore binds potassium ions on the outside with very high affinity. (genengnews.com)
  • These potassium ions flow into the transport complex, which causes a change in conformation and is driven by the use of energy. (genengnews.com)
  • The change in conformation also reduces the affinity for potassium ions, so the ions can be released inside the cell. (genengnews.com)
  • The system uses a channel which evolved to have a very high selective affinity for potassium ions with a pump that evolved for transport against a very high energy barrier," summarized Paulino. (genengnews.com)
  • Voltage-gated K + channels open in response to cell depolarization, reacting to the change in potential by movement of four charged Arg residues, which opens the pore and allows only K + ions to exit the cell. (sciencemag.org)
  • After being activated by an external signal, potassium channels open to allow ions through. (uchospitals.edu)
  • They found that when the potassium channel is open, water molecules quickly bind to tiny cavities within the protein structure, where they block the channel in a state that prevents the passage of ions. (uchospitals.edu)
  • Potassium channels function to conduct potassium ions down their electrochemical gradient, doing so both rapidly (up to the diffusion rate of K+ ions in bulk water) and selectively (excluding, most notably, sodium despite the sub-angstrom difference in ionic radius). (wikipedia.org)
  • In excitable cells, such as neurons, the delayed counterflow of potassium ions shapes the action potential. (wikipedia.org)
  • There are four major classes of potassium channels: Calcium-activated potassium channel - open in response to the presence of calcium ions or other signalling molecules. (wikipedia.org)
  • Using X-ray crystallography, profound insights have been gained into how potassium ions pass through these channels and why (smaller) sodium ions do not. (wikipedia.org)
  • The distance between the carbonyl oxygens and potassium ions in the binding sites of the selectivity filter is the same as between water oxygens in the first hydration shell and a potassium ion in water solution, providing an energetically-favorable route for de-solvation of the ions. (wikipedia.org)
  • Thus, it is energetically favorable for sodium ions to remain bound with water molecules in the extracellular space, rather than to pass through the potassium-selective ion pore. (wikipedia.org)
  • However, it was unclear whether the Kvβ protein functioned in a catalytic capacity in its interaction with Kv channels, which allow voltage-sensitive conductance of potassium ions that is critical for action potentials in excitable cells. (sciencemag.org)
  • Most cells in the body carry on their surface tiny pores through which potassium ions travel. (medicalxpress.com)
  • In controlling the flow of these positively charged ions, the channel helps the cell maintain its electrical balance. (medicalxpress.com)
  • Ion channels are integral membrane proteins allowing for the passive passage of specific inorganic ions across cell membranes, propelled by their electrochemical gradients. (frontiersin.org)
  • Cell membrane glycoproteins that are selectively permeable to potassium ions. (curehunter.com)
  • Computer model showing the structure of a bacterial potassium channel with four units arranged around an axis going through the first (and only visible) of four potassium ions (big purple sphere). (sciencephoto.com)
  • One feature of K + channels is that they conduct K + ions much better than slightly smaller Na + ions ( Hille, 2001 ). (plantphysiol.org)
  • La Jolla, CA Our brains are buzzing with electrical activity created by sodium and potassium ions moving in and out of neurons through specialized pores. (bio-medicine.org)
  • Ion channels are membrane-spanning proteins that form pores in cell membranes and act as pathways for the movement of inorganic ions into and out of the cell. (sciencephoto.com)
  • Kv channels are specific to potassium ions (K+) and are sensitive to voltage changes in the cell's membrane potential. (sciencephoto.com)
  • This channel, which is found in common bacteria, incorporates a subunit that accomplishes passive transport, as well as a subunit that accomplishes active transport. (genengnews.com)
  • The x-ray work, which was completed last year, established that the complex, which is called KdpFABC, contained one subunit with a channel architecture (KdpA), and another with an active transporter architecture (KdpB). (genengnews.com)
  • Details about these states-and a discussion of their significance-appeared November 26 in the journal Nature Communications , in an article titled, " Cryo-EM structures of KdpFABC suggest a K + transport mechanism via two inter-subunit half-channels . (genengnews.com)
  • Green: channel-like subunit KdpA. (genengnews.com)
  • Immunocytochemical experiments revealed the unexpected presence of immunoreactivity for the M-type potassium channel subunit Kv7.2 in the keratinocyte layer of intact rat paw skin and in keratinocytes isolated from the skin of 1-day-old rats and cultured in vitro for 3-10 days. (sigmaaldrich.com)
  • The Kvβ subunit of voltage-dependent potassium (Kv) channels has structural similarity to aldo-keto reductases (AKRs), enzymes that catalyze reduction of aldehyde groups to alcohols that are coupled to oxidation of an NADPH cofactor. (sciencemag.org)
  • The human KCND3 gene encodes the pore-forming subunit of Kv4.3, a voltage-gated potassium channel. (criver.com)
  • KCNIP2 encodes an auxiliary subunit of the channel. (criver.com)
  • Boston, MA -- ( SBWIRE ) -- 10/19/2016 -- Global Markets Direct's, 'Potassium Voltage Gated Channel Subfamily C Member 1 (Voltage Gated Potassium Channel Subunit Kv3.1 or Voltage Gated Potassium Channel Subunit Kv4 or KCNC1) - Pipeline Review, H2 2016', provides in depth analysis on Potassium Voltage Gated Channel Subfamily C Member 1 (Voltage Gated Potassium Channel Subunit Kv3.1 or Voltage Gated Potassium Channel Subunit Kv4 or KCNC1) targeted pipeline therapeutics. (sbwire.com)
  • The report provides comprehensive information on the Potassium Voltage Gated Channel Subfamily C Member 1 (Voltage Gated Potassium Channel Subunit Kv3.1 or Voltage Gated Potassium Channel Subunit Kv4 or KCNC1), targeted therapeutics, complete with analysis by indications, stage of development, mechanism of action (MoA), route of administration (RoA) and molecule type. (sbwire.com)
  • Additionally, the report provides an overview of key players involved in Potassium Voltage Gated Channel Subfamily C Member 1 (Voltage Gated Potassium Channel Subunit Kv3.1 or Voltage Gated Potassium Channel Subunit Kv4 or KCNC1) targeted therapeutics development and features dormant and discontinued projects. (sbwire.com)
  • Those more "typical" potassium channels preferentially carry outward (rather than inward) potassium currents at depolarized membrane potentials, and may be thought of as "outwardly rectifying. (wikipedia.org)
  • When first discovered, inward rectification was named "anomalous rectification" to distinguish it from outward potassium currents. (wikipedia.org)
  • Inward rectifiers also differ from tandem pore domain potassium channels , which are largely responsible for "leak" K + currents. (wikipedia.org)
  • Other inwardly rectifying channels, termed "strong inward rectifiers," carry very little outward current at all, and are mainly active at voltages negative to the K + reversal potential, where they carry inward current (the much larger currents below the 0 nA line in figure 1). (wikipedia.org)
  • Three distinct K + channels were examined: the inward rectifier (I K1 ), the delayed rectifier (I K ), and the transient outward (I to ) currents. (ahajournals.org)
  • Salicylate-induced hearing loss is believed to arise from a reduction in the electromotile response of outer hair cells (OHCs) and/or reduction of KCNQ4 potassium currents in OHCs which decreases the driving force for the transduction current. (mendeley.com)
  • Therefore, enhancing OHC potassium currents could potentially prevent salicylate-induced temporary hearing loss. (mendeley.com)
  • These results suggest that ICA-105665 partially compensates for salicylate induced cochlear hearing loss by enhancing KCNQ2/3 and KCNQ3/5 potassium currents and the motility of OHCs. (mendeley.com)
  • Outward potassium ion currents activated upon depolarization would counteract the depolarizing action of inward currents carried either by sodium ion (Na+) or Ca2+. (novapublishers.com)
  • Macroscopic currents of wild-type KirBac1.1 are K(+) selective and spermine insensitive, but blocked by Ba(2+), similar to "weakly rectifying" eukaryotic Kir1.1 and Kir6.2 channels. (nih.gov)
  • Application of the M-channel enhancer retigabine (3-10 μM) to isolated cultured rat keratinocytes: (a) increased outward membrane currents recorded under voltage clamp, (b) produced ~3 mV hyperpolarization at rest, (c) enhanced ~3-fold the release of ATP induced by the TRPV3 agonist carvacrol (1 mM) and (d) increased the amplitude of the carvacrol-induced intracellular Ca(2+) transient measured with Fura-2. (sigmaaldrich.com)
  • With $246,000 in funding from FRAXA over 2012-2014, the Yale University team of Leonard Kaczmarek, PhD, showed that loss of FMRP leads to an increased Kv3.1 potassium currents and decreased Slack potassium currents in neurons. (fraxa.org)
  • When overexpressed in heterologous systems, KCNE3 is able to interact with several pore-forming K+ channel alpha subunits greatly modifying their currents. (hu-berlin.de)
  • Hence, our current knowledge of the effects of disease on vascular K + channel expression is somewhat indirect and almost exclusively relies on interpretation of functional or electrophysiological data (eg, recordings of vessel tone or diameter, vascular muscle cell E m , or whole-cell or single-channel currents in isolated myocytes under voltage-clamp conditions) obtained in the presence of pharmacological modulators of K + channels. (ahajournals.org)
  • It is a potassium channel blocker that inhibits both transient outward (1 to ) and delayed rectifier (1 k ) potassium currents. (bmj.com)
  • Baranauskas G, Tkatch T, Nagata K, Yeh JZ, Surmeier DJ (2003) Kv3.4 subunits enhance the repolarizing efficiency of Kv3.1 channels in fast-spiking neurons. (springer.com)
  • Cooper EC, Aldape KD, Abosch A, Barbaro NM, Berger MS, Peacock WS, Jan YN, Jan LY (2000) Colocalization and coassembly of two human brain M-type potassium channel subunits that are mutated in epilepsy. (springer.com)
  • However, when both subunits of the K ATP channel Kir 6.2/SUR 2A were cotransfected in COS-7 cells, a phenotype was produced in which pinacidil was capable of markedly attenuating the calcium loading produced by hypoxia-reoxygenation. (ahajournals.org)
  • In situ hybridization revealed the presence of different BK channel splice variants (X1 +24 , X2 +92 , SS2 +174 and SS4 +81 ) in combination with β 1, β 2, and β 4 subunits in rat cerebral arteries [ 13 ]. (hindawi.com)
  • Potassium channels have a tetrameric structure in which four identical protein subunits associate to form a fourfold symmetric (C4) complex arranged around a central ion conducting pore (i.e., a homotetramer). (wikipedia.org)
  • All potassium channel subunits have a distinctive pore-loop structure that lines the top of the pore and is responsible for potassium selective permeability. (wikipedia.org)
  • There are over 80 mammalian genes that encode potassium channel subunits. (wikipedia.org)
  • Application of a Kvβ substrate to Kv channels in inside-out patches from oocytes expressing the channel subunits decreased channel inactivation and increased peak current and steady-state current through the channel. (sciencemag.org)
  • Aside from the possible presence of accessory subunits (see below), in the Kv channels four pore subunits form a tetrameric structure surrounding a central conduction pathway (Figure 2 ). (frontiersin.org)
  • At least eight major groups of K channels exist and they are made up of dozens of different subunits. (curehunter.com)
  • The expression of different types of GIRK channel subunits in neurons along with varying levels of specific trafficking proteins, such as SNX27, could dictate the ultimate expression levels on the surface of the plasma membrane, and therefore the strength of inhibitory signaling in the brain, says Slesinger. (bio-medicine.org)
  • The BK channel is a member of the superfamily of voltage-gated channels that assembles as a homotetramer of pore-forming Slo1 (α) subunits. (rupress.org)
  • The cover image for the January 7 issue of Biophysical Journal is an artistic rendering of the KcsA protein (blue), a bacterial potassium channel, embedded in a cell membrane (cyan) and surrounded by water (red/white). (biophysics.org)
  • When the signaling molecule cAMP docks onto the potassium channel, it causes a rearrangement and shift in the protein scaffold," explains Julia Kowal, first author of this study. (innovations-report.com)
  • Data from the hippocampus and DRN indicate the 5-HT induced hyperpolarisation to be sensitive to Pertussis Toxin (PTX) and irreversibly mimicked by GTPγS, a non-hydrolysable analogue of GTP, suggesting the involvement of a G protein in K + channel activation. (springer.com)
  • These results suggest that the cardiac K ATP channel protein possesses endogenous cytoprotective properties when transfected into a noncardiac cell type. (ahajournals.org)
  • Furthermore, potassium ion channels may be a target protein for the research and development of a therapeutic agent for various diseases concerning the lungs, heart, nerves, eyes, and pancreas. (novapublishers.com)
  • We have expressed pure full-length His-tagged KirBac1.1 protein in Escherichia coli and obtained voltage clamp recordings of recombinant channel activity in excised membrane patches from giant liposomes. (nih.gov)
  • A paper on this work has been published in Journal of Neuroscience on 2010 August 4: Fragile X mental retardation protein is required for rapid experience-dependent regulation of the potassium channel Kv3.1b by Leonard Kaczmarek, PhD and Jack Kronengold, PhD Our laboratory has investigated how the excitability of neurons becomes modified in the absence of the FMRP protein. (fraxa.org)
  • We have found that the levels of two potassium channels, termed Slack and Kv3.1 are altered in mice that lack this protein. (fraxa.org)
  • With a $282,000 funding from FRAXA Research Foundation, Dr. Leonard Kaczmarek and colleagues explored association of Slack channels with the Fragile X protein (FMRP). (fraxa.org)
  • The basic architecture of the voltage-dependent K + channels (Kv channels) corresponds to a transmembrane protein core in which the permeation pore, the voltage-sensing components and the gating machinery (cytoplasmic facing gate and sensor-gate coupler) reside. (frontiersin.org)
  • Each Potassium Channel Kv3.1 Peptide and Potassium Channel Kv3.1 Protein is fully covered by our Guarantee+, to give you complete peace of mind and the support when you need it. (novusbio.com)
  • TBK1 activity regulates binding of the channel with Hax-1, an anti-apoptotic protein required for survival of cerebellar neurons, and that embeds Kv3.3 in a stable actin cytoskeleton at the plasma membrane. (ssrn.com)
  • Cells that express the mutant channel have increased internalization of Hax-1 and accumulate multivesicular bodies containing this cell survival protein, coupled to depolarization-induced loss of the channels themselves. (ssrn.com)
  • Our studies indicate that the activation of Kv3.3 channels is linked directly to TBK1 activity and channel mutations enhance internalization of the cell survival protein Hax-1 to which they are bound. (ssrn.com)
  • It is postulated that the precursor channel protein resembled the pore module of modern K + channels ( Fig. 1A ). (plantphysiol.org)
  • In this brief review, we suggest that a viral-encoded K + protein might be the evolutionary ancestor of all K + channel proteins. (plantphysiol.org)
  • GIRK channels (short for G-protein-coupled inwardly rectifying potassium channels) a subtype of the many different potassium channels in the brain are widely distributed in the brain and regulate neuron-to-neuron communication. (bio-medicine.org)
  • U-0126, the mitogen-activated protein kinase inhibitors, could reverse macrophage migration induced by Kv1.3 channel overexpression. (sigmaaldrich.com)
  • This protein belongs to a family of proteins, ion channels, which control the electrical excitability of the brain. (fraxa.org)
  • The Kir2.6 also known as inward rectifier potassium channel 18 is a protein that in humans is encoded by the KCNJ18 gene. (wikipedia.org)
  • In terms of function, these proteins transport potassium (K + ) , with a greater tendency for K + uptake than K + export. (wikipedia.org)
  • All the strategies developed in this review could be extended to studies on other ion channels and proteins as well. (nih.gov)
  • This domain is found in a variety of potassium channel proteins, including the two membrane helix type ion channels found in bacteria [ PMID: 11836519 ]. (ebi.ac.uk)
  • Potassium ion channel activity is also essentially regulated by the intracellular signal transduction pathways, such as receptors' (G proteins) second messenger molecules processes in the physiological condition. (novapublishers.com)
  • K + channels are tetrameric membrane proteins that selectively conduct K + across cellular membranes. (nature.com)
  • Many of these techniques study potassium channels as cellular proteins as well as the resultant membrane biophysics. (springer.com)
  • The ATP-sensitive potassium channels (K ATP ), 45-kD proteins with ATP-binding domains, 1 are thought to play a key role in the glucose-induced release of insulin from pancreatic β-cells. (ahajournals.org)
  • We offer Potassium Channel Kv3.1 Peptides and Potassium Channel Kv3.1 Proteins for use in common research applications: Blocking/Neutralizing, Control. (novusbio.com)
  • Our Potassium Channel Kv3.1 Peptides and Potassium Channel Kv3.1 Proteins can be used in a variety of model species: Human. (novusbio.com)
  • Choose from our Potassium Channel Kv3.1 Peptides and Proteins. (novusbio.com)
  • We found that Kv3.3 channels bind and stimulate Tank Binding Kinase 1 (TBK1), an enzyme that controls trafficking of membrane proteins into multivesicular bodies. (ssrn.com)
  • Phylogenetic studies and structure/function properties of channel proteins have led to the hypothesis that the complex K + channels in animals and plants evolved from a simple bacterial precursor channel ( Anderson and Greenberg, 2001 ). (plantphysiol.org)
  • To address the question of the origin of the precursor of K + channels, it is informative to mention a few recent ideas on evolution and the discovery of K + channel proteins coded by some viruses. (plantphysiol.org)
  • Now, using a proteomics approach, Slesinger and his team searched for proteins that might regulate the activity of GIRK3 channels and found SNX27. (bio-medicine.org)
  • The roles of anchoring proteins, molecular motors and kinases are explored and recent findings on channel internalization and trafficking are presented. (portlandpress.com)
  • Barhanin J, Lesage F, Guillemare E, Fink M, Lazdunski M, Romey G. K(V)LQT1 and lsK (minK) proteins associate to form the I(Ks) cardiac potassium current. (springer.com)
  • The intermediate-conductance Ca 2+ -activated K + channel (K Ca 3.1) has been proposed to promote mitogenesis in several cell types and contribute to disease states characterized by excessive proliferation. (pnas.org)
  • High-conductance, 'big' potassium (BK) channels encoded by the Slo gene family are among the largest and most complex of the extended family of potassium channels. (nih.gov)
  • Membrane potential of cerebrovascular smooth muscle cells and thus dilation and constriction of cerebral arteries are directly dependent on potassium conductance [ 5 , 6 ]. (hindawi.com)
  • At the single-channel level, KirBac1.1 channels show numerous conductance states with two predominant conductances (15 pS and 32 pS at -100 mV) and marked variability in gating kinetics, similar to the behavior of KcsA in recombinant liposomes. (nih.gov)
  • Given that conductance of Kvβ channels is known to be altered in response to hypoxia or oxidative stress, the authors favor the latter possibility and anticipate that further elucidation of the interaction mechanism and identification of the physiological substrates of Kvβ should settle the matter once and for all. (sciencemag.org)
  • Although little is known about voltage independent potassium channels in microglia, special attention emerges on small (SK/ KCNN1 -3/K Ca 2) and intermediate (IK/ KCNN4 /K Ca 3.1)-conductance calcium-activated potassium channels as regulators of microglial activation in the field of research on neuroinflammation and neurodegeneration. (frontiersin.org)
  • Whole cell experiments, with high (144 mM) intracellular and extracellular potassium as the principal conductive species, show some variation between cells in the current-voltage relationship (mean whole-cell conductance at physiological potentials being 2.7 nS). (moleculardevices.com)
  • The channels show a mean inward conductance (with 144 mM potassium in the pipette) of 44 pS and an outward conductance of 23 pS. (moleculardevices.com)
  • Large conductance Ca 2+ -activated K + (BK Ca ) channels are activated by intracellular Ca 2+ and also by E m depolarization and are particularly abundant in vascular smooth muscle cells. (ahajournals.org)
  • Large conductance calcium- and voltage-dependent BK potassium channels (aka BK Ca , MaxiK, Slo1, KCa1.1, and KCNMA1) are expressed in a wide variety of tissues throughout the body and are activated by both intracellular Ca 2+ and membrane depolarization. (rupress.org)
  • However, when the membrane potential is set positive to the channel's resting potential (e.g. +60 mV), these channels pass very little current. (wikipedia.org)
  • They, along with the "leak" channels, establish the resting membrane potential of the cell. (wikipedia.org)
  • Channels and transporters stud the cell membrane, allowing exchange with the outside environment or the larger organism. (biophysics.org)
  • Potassium channels are embedded in the membrane of cells. (innovations-report.com)
  • The ATP-dependent potassium channels (K ATP channels) were originally identified in isolated membrane patches prepared from guinea pig ventricular myocytes by Noma 1 in 1983. (ahajournals.org)
  • Since their discovery in cardiac cells, K ATP channels have also been discovered in many other tissues, such as smooth muscle, skeletal muscle, pancreas, and brain, in which they have been shown to couple cellular metabolism to membrane electrical activity. (ahajournals.org)
  • 6 Membrane hyperpolarization or a slowing of membrane depolarization would also be an expected consequence of K ATP channel opening, and this would also be expected to slow calcium entry through L-type channels and prevent the reversal of the sodium-calcium exchanger, which normally extrudes calcium for sodium. (ahajournals.org)
  • Potassium ion (K+) channels are ubiquitous components and are widely distributed on the surface of the cell membrane in various tissues. (novapublishers.com)
  • The potassium ion current across the plasma membrane is considered to have two main physiological functions, one for determining the membrane potential and the other regulating the electrical activity. (novapublishers.com)
  • Membrane hyperpolarization would reduce the excitability of the membrane by shifting the membrane potential away from the threshold for excitation and would inhibit, where it existed, calcium ion (Ca2+) influx through voltage-gated Ca2+ channels by closing the Ca2+ channel. (novapublishers.com)
  • Therefore, potassium ion channels show the physiological effects in each tissue via membrane potential mediated Ca2+ dynamics (for example, excitation-contraction coupling in muscle). (novapublishers.com)
  • Healthy cerebrovascular myocytes express members of several different ion channel families which regulate resting membrane potential, vascular diameter, and vascular tone and are involved in cerebral autoregulation. (hindawi.com)
  • Tandem pore domain potassium channel - are constitutively open or possess high basal activation, such as the "resting potassium channels" or "leak channels" that set the negative membrane potential of neurons. (wikipedia.org)
  • Le potentiel de membrane au repos (PMR) des CML circulaires a été dépolarisé de manière plus significative que celui des CML obliques en raison de la plus forte perméabilité au Na + et au Cl - dans le muscle circulaire que dans le muscle oblique. (ingentaconnect.com)
  • Une forte réduction du courant sortant a été observée en présence de 4-aminopyridine, tandis que les bloqueurs de BK Ca ont eu un effet limité sur le courant sortant activé par le potentiel de membrane dans le muscle oblique. (ingentaconnect.com)
  • Inactivation is a process by which an open channel enters a stable non-conducting state after a maintained depolarizing change in membrane potential. (frontiersin.org)
  • Blocking voltage-dependent potassium channels prolongs presynaptic cell membrane depolarization, which enhances calcium transport into nerve endings. (medscape.com)
  • Voltage-gated K+ channels are important determinants of neuronal membrane excitability. (novusbio.com)
  • Abstract -Potassium ion (K + ) channel activity is a major regulator of vascular muscle cell membrane potential ( E m ) and is therefore an important determinant of vascular tone. (ahajournals.org)
  • Left: Activation (opening) of a K + channel (gray) in the cell membrane allows K + to flux out of the cell, causing a decrease in E m (ie, hyperpolarization) and consequent inhibition (closure) of voltage-activated Ca 2+ channels (white) and a decrease in cytosolic Ca 2+ levels, resulting in vascular muscle relaxation (vasodilatation). (ahajournals.org)
  • Effects of KCNE2 on HCN isoforms: distinct modulation of membrane expression and single channel properties. (springer.com)
  • In vivo, chick chorioallantoic membrane (CAM) angiogenesis was similarly enhanced by the direct K ATP channel activator SG-209 (2-nicotinamidoethyl acetate) and by CNP. (aspetjournals.org)
  • Inwardly rectifying potassium channels, such as Kir2.6, maintain resting membrane potential in excitable cells and aid in repolarization of cells following depolarization. (wikipedia.org)
  • Prof. Henning Stahlberg's team at the Biozentrum of the University of Basel has now elucidated the full structure of a bacterial counterpart of this type of potassium channel, which has provided new insights into its functioning. (innovations-report.com)
  • A type of potassium channel called TRESK is thought to control the excitability of peripheral sensory neurons that detect pain, heat, cold, and touch. (medicalxpress.com)
  • An ATP-sensitive potassium channel (or K ATP channel) is a type of potassium channel that is gated by intracellular nucleotides, ATP and ADP. (acronymattic.com)
  • Using all-atom molecular dynamics simulations, we show how a voltage-gated potassium channel (KV) switches between activated and deactivated states. (sciencemag.org)
  • Molecular dynamics simulations show how a voltage-gated channel closes. (sciencemag.org)
  • There are many types of potassium ion channels (voltage-gated K+ channels, ATP-sensitive K+ channels, Ca2+-activated K+ channels, etc.), and each type of potassium ion channel has its own characteristic features concerning electrophysiology and molecular biology in each potassium ion channel. (novapublishers.com)
  • Recent results from X-ray crystallography and molecular dynamics suggest that the gates are coupled and that inactivation is prompted by channel opening, mediated via a series of intrasubunit steric contacts involving F103 with T74, T75, and M96 and an intersubunit contact with the neighboring I100 side chain ( 4 ⇓ - 6 , 24 , 25 ). (pnas.org)
  • Using molecular simulations that modeled a potassium channel and its immediate cellular environment, atom for atom, University of Chicago scientists have revealed this new mechanism in the function of a nearly universal biological structure, with implications ranging from fundamental biology to the design of pharmaceuticals. (uchospitals.edu)
  • This gives us better understanding of fundamental biology and should improve the rational design of drugs, which often target the inactivated state of channels' said Benoît Roux, PhD, professor of biochemistry and molecular biology at the University of Chicago. (uchospitals.edu)
  • However potassium channels found in bacteria are amongst the most studied of ion channels, in terms of their molecular structure. (wikipedia.org)
  • Here we review the present knowledge about the molecular organization of these intracellular channel regions and their role in both setting and controlling Kv voltage-dependent gating properties. (frontiersin.org)
  • These processes are only beginning to be unravelled and involve modulators of channel synthesis and assembly, post-translational processing, various molecular motors and an increasing number of modifying enzymes and molecular anchors. (portlandpress.com)
  • As further progress is made in the development of more selective drugs and through molecular approaches such as gene targeting technology in mice, specific K + channel abnormalities and their causes in particular diseases should be more readily identified, providing novel directions for vascular therapy. (ahajournals.org)
  • While molecular biological studies are revealing a large diversity in the subtypes of K + channels that are normally expressed in vascular muscle, 7 it is noteworthy that there is still very little information available at the molecular level regarding regulation of K + channel expression and function in vascular disease. (ahajournals.org)
  • Molecular model of a voltage-gated potassium (Kv) ion channel. (sciencephoto.com)
  • The goal of this perspective is to provide an overview on the role and molecular basis of conformational coupling between functional domains in BK channels and outline some of the questions that remain to be answered. (rupress.org)
  • Fagni L, Chavis P, Ango F, Bockaert J (2000) Complex interactions between mGluRs, intracellular Ca2+ stores and ion channels in neurons. (springer.com)
  • Increasing evidence suggests that ion channels also play a role in cell proliferation by enhancing intracellular Ca 2+ signaling and affecting cell cycle progression ( 13 , 14 ). (pnas.org)
  • It has been hypothesized that transmembrane allostery is the basis for inactivation of the potassium channel KcsA: opening the intracellular gate is spontaneously followed by ion expulsion at the extracellular selectivity filter. (pnas.org)
  • New concepts on potassium channel function in neuroinflammation suggest that they regulate mechanisms of microglial activation, including intracellular calcium homeostasis, morphological alterations, pro-inflammatory cytokine release, antigen presentation, and phagocytosis. (frontiersin.org)
  • Abstract The ATP-sensitive potassium channels (K ATP ) are activated either by a decrease in intracellular ATP content or by a lowering of the ATP-ADP ratio such as during stroke. (ahajournals.org)
  • Increases intracellular calcium concentrations in nerve endings by blocking voltage-dependent potassium channels. (medscape.com)
  • Guanidine is thought to act by increasing free intracellular calcium concentrations through inhibition of mitochondrial respiration by blocking potassium channels, and thus prolonging the nerve terminal action potential. (medscape.com)
  • A novel intracellular traffic coordinator pulls potassium channels from their job and whisks them to the recycling plant when not needed to put a damper on brain cells excitability, they report in the September issue of Nature Neuroscience. (bio-medicine.org)
  • The Kv3.1 potassium channel is expressed at high levels in neurons that characteristically fire rapid trains of action potentials (Gan et al. (novusbio.com)
  • Discover related pathways, diseases and genes to Potassium Channel Kv3.1. (novusbio.com)
  • Neurons express a large number of different voltage-gated potassium (Kv) channels with distinct biophysical and biochemical properties. (springer.com)
  • In particular, recent findings suggested that SK/K Ca 2 channels, by regulating calcium homeostasis, may elicit a dual mechanism of action with protective properties in neurons and inhibition of inflammatory responses in microglia. (frontiersin.org)
  • Here, we review the particular role of SK/K Ca 2 channels for [Ca 2+ ] i regulation in microglia and neurons, and we discuss the potential impact for further experimental approaches addressing novel therapeutic strategies in neurological diseases, where neuronal cell death and neuroinflammatory processes are prominent. (frontiersin.org)
  • Kv1.4 channels expressed in neurons are therapeutic targets in neuropathic pain. (criver.com)
  • 1999). Particularly high levels of this channel are found in neurons of the auditory brainstem. (novusbio.com)
  • Top: Normal distribution of TRESK channels (green) in facial pain sensory neurons. (medicalxpress.com)
  • Even though these channels are found throughout the neurons sensing both body and facial pain , channel mutations are linked only with headaches and not body pain. (medicalxpress.com)
  • These results indicate that TRESK channels have cell-specific roles and are responsible for regulating pain in facial sensory neurons , making them a target for migraine treatment research. (medicalxpress.com)
  • These neurotransmitter molecules then travel across the space between neurons and set off an electrical signal in the adjacent cell unless the receiving end is decorated with so called GIRK channels, that is. (bio-medicine.org)
  • Since potassium channels are intrinsically involved in repolarization, this study was designed to evaluate the effect of the nonsedating antihistamines on potassium channel modulation. (ahajournals.org)
  • Some illustrative examples about the relevance of these cytoplasmic domains determining the possibilities for modulation of Kv channel gating by cellular components are also considered. (frontiersin.org)
  • The effects of extracellular acidosis on IhERG kinetics were preserved when the shortened hERG I b isoform was studied, indicating that a full-length N-terminus is not necessary for acidic modulation of hERG channel function. (bl.uk)
  • Potassium channel activation and inactivation is fundamental to many physiological functions including muscle contraction and the generation of synaptic action potentials ( 1 ). (pnas.org)
  • Like many potassium channels, it exhibits ( 4 , 6 , 22 , 23 ) slow, spontaneous inactivation involving the residues near the extracellular selectivity filter subsequent to channel activation. (pnas.org)
  • Although it's not yet known what causes SUDEP in humans, inactivation of potassium channels genes have been linked to SUDEP in animal models. (mdanderson.org)
  • Better understanding of this ubiquitous biological system will change how people think about inactivation and recovery of these channels, and has the potential to someday impact human health. (uchospitals.edu)
  • This includes the influence that they exert on Kv rapid/N-type inactivation and on activation/deactivation gating of Shaker -like and eag -type Kv channels. (frontiersin.org)
  • Inhibition of hERG channels prolongs the ventricular action potential and correspondingly the QT-interval with the risk of torsade de pointes arrhythmias which may result in sudden cardiac death. (mdpi.com)
  • The human ether-a-go-go-related gene (hERG) encodes channels mediating the rapid delayed rectifier K+ current (IKr). (bl.uk)
  • Smith PL, Baukrowitz T, Yellen G. The inward rectification mechanism of the HERG cardiac potassium channel. (springer.com)
  • Sanguinetti MC, Jiang C, Curran ME, Keating MT. A mechanistic link between an inherited and an acquired cardiac arrhythmia: HERG encodes the IKr potassium channel. (springer.com)
  • Trudeau MC, Warmke JW, Ganetzky B, Robertson GA. HERG, a human inward rectifier in the voltage-gated potassium channel family. (springer.com)
  • MiRP1 forms IKr potassium channels with HERG and is associated with cardiac arrhythmia. (springer.com)
  • To determine the cellular electrophysiological basis for the proarrhythmic effects of these drugs, this study was designed to investigate the actions of two H 1 receptor antagonists, terfenadine and astemizole, on various potassium (K + ) channels of cardiac myocytes. (ahajournals.org)
  • Cardiac myocytes expressing the native endogenous K ATP channel were also exposed to the same chemical hypoxia-reoxygenation protocol and demonstrated a marked increase in cellular calcium that was significantly attenuated by pinacidil, an effect that was abolished by glyburide. (ahajournals.org)
  • However, it remains unclear whether seizure and sudden death are two separate manifestations of potassium channel deficiency in the brain and the heart, or whether seizures predispose the heart to lethal cardiac arrhythmia," said Yeh. (mdanderson.org)
  • By contributing to the regulation of the cardiac action potential duration in cardiac muscle, malfunction of potassium channels may cause life-threatening arrhythmias. (wikipedia.org)
  • These ATP-sensitive potassium channels play a role in regulating cardiac and skeletal muscle action potentials. (doctorslounge.com)
  • In summary, this study demonstrates that sarcolemmal K ATP channels not only respond to metabolic stress but continuously control energy use by cardiac and skeletal muscles, thereby promoting body energy conservation. (doctorslounge.com)
  • The proper trafficking and localization of cardiac potassium channels is profoundly important to the regulation of the regionally distinct action potentials across the myocardium. (portlandpress.com)
  • Cooper EC, Milroy A, Jan YN, Jan LY, Lowenstein DH (1998) Presynaptic localization of Kv1.4-containing A-type potassium channels near excitatory synapses in the hippocampus. (springer.com)
  • Diochot S, Schweitz H, Béress L, Lazdunski M (1998) Sea anemone peptides with a specific blocking activity against the fast inactivating potassium channel Kv3.4. (springer.com)
  • Whole-cell current recordings of K ir 2 inwardly-rectifying potassium channels expressed in an HEK293 cell . (wikipedia.org)
  • In the context of single cells, channel blockers abrogate Kv1.3 channel function in patch-clamp experiments. (nature.com)
  • A significant portion of the outward current was due to non-BK Ca , especially in sling muscle, and likely delayed rectifier K + channels (K DR ). There was a large reduction in outward current with 4-aminopyridine (4-AP) in sling muscle, while BK Ca blockers had a limited effect on the voltage-activated outward current in sling muscle. (ingentaconnect.com)
  • Kelly J.S., Larkman P., Penington N.J., Rainnie D.G., McAllister-Williams H., Hodgkiss J. (1991) Serotonin Receptor Heterogeneity and the Role of Potassium Channels in Neuronal Excitability. (springer.com)
  • Your search returned 25 potassium channel tetramerization domain containing 20 ELISA ELISA Kit across 1 supplier. (biocompare.com)
  • Inward rectifier potassium channels. (nih.gov)
  • Expression cloning of the first inward rectifier K channel (Kir) genes provided the necessary break-through that has led to isolation of a family of related clones encoding channels with the essential functional properties of classical inward rectifiers, ATP-sensitive K channels, and muscarinic receptor-activated K channels. (nih.gov)
  • Inward-rectifier potassium channels ( K ir , IRK ) are a specific subset of potassium channels . (wikipedia.org)
  • These channels differ from the potassium channels that are typically responsible for repolarizing a cell following an action potential , such as the delayed rectifier and A-type potassium channels. (wikipedia.org)
  • KirBac1.1 is a prokaryotic homologue of eukaryotic inward rectifier potassium (Kir) channels. (nih.gov)
  • Primary structure and functional expression of a mouse inward rectifier potassium channel [see comments]. (nii.ac.jp)
  • A novel ATP-dependent inward rectifier potassium channel expressed predominantly in glial cells. (nii.ac.jp)
  • A delayed rectifier subtype of shaker potassium channels that is selectively inhibited by a variety of SCORPION VENOMS. (curehunter.com)
  • Kir2.6 is an inward-rectifier potassium ion channel. (wikipedia.org)
  • Warmke JW, Ganetzky B. A family of potassium channel genes related to eag in Drosophila and mammals. (springer.com)
  • The compounds are useful as inhibitors of potassium channel function and in the treatment and prevention of arrhythmia, I.sub.Kur-associated disorders, and other disorders mediated by ion channel function. (patentgenius.com)
  • In these COS-7 cells deficient in K ATP channels, the K ATP channel opener pinacidil had no significant effect on calcium loading produced by chemical hypoxia-reoxygenation injury. (ahajournals.org)
  • For more examples of pharmacological modulators of potassium channels, see potassium channel blocker and potassium channel opener. (wikipedia.org)
  • Looking forward, potassium channel opener drugs could rescue some symptoms of Fragile X in humans. (fraxa.org)
  • A potassium channel opener is a type of drug which facilitates ion transmission through potassium channels. (wikipedia.org)
  • METHODS: Male Sprague-Dawley rats were pretreated with intravenous infusion of propofol (Prop), a selective mitochondrial KATP channel inhibitor 5-hydroxydecanoate (5-HD), propofol plus 5-HD (Prop+5-HD), a potent mitochondrial K(ATP) channel opener diazoxide (DZ) or NS, respectively. (biomedsearch.com)
  • Mutations in KCNC3, which encodes the Kv3.3 potassium channel, are linked to degeneration of the cerebellum (SCA13, spinocerebellar ataxia type 13). (ssrn.com)
  • Thirdly, both qualitative and quantitative approaches are utilized to analyze structural features of modulators of potassium channels. (nih.gov)
  • In Potassium Channels: Methods and Protocols , experts in the field present a range of experimental approaches that have been developed to investigate potassium channel structure, function, pharmacology, cell biology, gene expression, and their role in disease. (springer.com)
  • Using a nonselective potassium channel blocker, the CsCl, the relaxant effect of p -cymene was attenuated. (hindawi.com)
  • Some examples include: Diazoxide vasodilator used for hypertension, smooth muscle relaxing activity Minoxidil vasodilator used for hypertension, also used to treat hair loss Nicorandil vasodilator used to treat angina Pinacidil Retigabine, an anticonvulsant Flupirtine, analgesic with muscle relaxant and anticonvulsant properties Potassium channel blocker Mizutani S, Prasad SM, Sellitto AD, Schuessler RB, Damiano RJ, Lawton JS (August 2005). (wikipedia.org)
  • Amifampridine, a voltage-dependent potassium channel blocker, is indicated for treatment of LEMS. (medscape.com)
  • Glyburide (Glibenclamide) is a known blocker of vascular ATP-sensitive K+ channels (KATP), used in the treatment of type 2 diabetes. (selleckchem.com)
  • OBJECTIVE To determine the efficacy and safety of the potassium channel blocker tedisamil versus placebo in the treatment of patients with stable angina. (bmj.com)
  • Effects of propofol on ischemia-induced ventricular arrhythmias and mitochondrial ATP-sensitive potassium channels. (biomedsearch.com)
  • AIM: To investigate the potential of propofol in suppressing ventricular arrhythmias and to examine whether mitochondrial ATP-sensitive potassium channels are involved. (biomedsearch.com)
  • CONCLUSION: Propofol preconditioning suppresses ischemia-induced ventricular arrhythmias in the rat heart, which are proposed to be caused by opening of mitochondrial K(ATP) channels. (biomedsearch.com)
  • [4] IRK channels possess a pore domain, homologous to that of voltage-gated ion channels , and flanking transmembrane segments (TMSs). (wikipedia.org)
  • Firstly, we try to summarize the latest developments in structure determinants and regulation mechanism of all types of potassium channels. (nih.gov)
  • We hope that our work will not only lead to a consensus on the mechanism of ion transport in potassium channels, but also contribute to solving the mystery of fast and selective transport. (biophysics.org)
  • The mechanism of ion channel voltage gating-how channels open and close in response to voltage changes-has been debated since Hodgkin and Huxley's seminal discovery that the crux of nerve conduction is ion flow across cellular membranes. (sciencemag.org)
  • Conclusions These findings suggest that the mechanism of action of the rare proarrhythmic effects of the nonsedating antihistamines appears to be secondary to potassium channel blockade. (ahajournals.org)
  • The mechanism of K + channel closure is less clear as it is unaffected by PTX or activation of adenylate cyclase, however there is indirect evidence that the phosphoinositide pathway may be involved from the cloned 5-HT1c receptor which also closes a K + channel in cell lines. (springer.com)
  • Unexpectedly, the structures suggest a translocation pathway through two half-channels along KdpA and KdpB, uniting the alternating-access mechanism of actively pumping P-type ATPases with the high affinity and selectivity of K + channels," the article's authors indicated. (genengnews.com)
  • Since the original study by Noma in 1983, 1 there has been a great deal of interest in the mechanism by which opening the K ATP channel by drugs or brief periods of ischemia produces a cardioprotective effect. (ahajournals.org)
  • Studies at Yale University and elsewhere are showing that FMRP plays a significant role in the regulation of potassium channels. (fraxa.org)
  • In fact, sodium is actually smaller than potassium, so selection by simple size exclusion is not possible. (biophysics.org)
  • We propose a mechanistic model for the sodium/potassium/calcium voltage-gated ion channel superfamily that reconciles apparently conflicting experimental data. (sciencemag.org)
  • Voltage-sensing domains (VSDs) control the activity of voltage-gated ion channels to regulate the ion flow that underlies nerve conduction. (sciencemag.org)
  • Voltage-gated potassium channel - are voltage-gated ion channels that open or close in response to changes in the transmembrane voltage. (wikipedia.org)
  • Delmas P, Brown DA (2005) Pathways modulating neural KCNQ/M (Kv7) potassium channels. (springer.com)
  • Browne DL, Gancher ST, Nutt JG, Brunt ERP, Smith EA, Kramer P, Litt M (1994) Episodic ataxia/myokymia syndrome is associated with point mutations in the human potassium channel gene KCNA1. (springer.com)
  • There is genetic evidence that the plethora of K + channels results from several major genetic events, such as gene fusions and gene duplications ( Anderson and Greenberg, 2001 ). (plantphysiol.org)
  • The tandem architecture of the TWIK channels, with the tandem 2TM structure (2*2TM) structure, probably occurred after a gene duplication of the pore module. (plantphysiol.org)
  • Gene fusion of the precursor to the latter could explain the structure of the TOK channel in which the 2TM motive and the 6TM motive are combined (6+2TM). (plantphysiol.org)
  • S. B. Long, E. B. Campbell, R. MacKinnon, Crystal structure of a mammalian voltage-dependent Shaker family K + channel. (sciencemag.org)
  • KcsA is a 160-residue pH-activated homotetrameric K + channel isolated from the soil bacterium Streptomyces lividans ( 2 , 3 ) with high sequence homology and functional similarity to mammalian potassium channels ( 4 ). (pnas.org)
  • Here, changes in calcium and potassium channel expression and function in animal models of subarachnoid hemorrhage and transient global ischemia are systematically reviewed and their clinical significance discussed. (hindawi.com)
  • A channel that is "inwardly-rectifying" is one that passes current (positive charge) more easily in the inward direction (into the cell) than in the outward direction (out of the cell). (wikipedia.org)
  • Simply put, this channel passes much more current in the inward direction than the outward one, at its operating voltage range. (wikipedia.org)
  • These channels are not perfect rectifiers, as they can pass some outward current in the voltage range up to about 30 mV above resting potential. (wikipedia.org)
  • If the low K + state is similar to the inactivated state of KcsA achieved by lowering the pH, it is expected that structural changes indicative of channel opening observed at low [K + ] would occur not only in the selectivity filter but also in the pH gate and the hinge region. (pnas.org)
  • The successful patch clamping of KirBac1.1 confirms that this prokaryotic channel behaves as a bona fide Kir channel and opens the way for combined biochemical, structural, and electrophysiological analysis of a tractable model Kir channel, as has been successfully achieved for the archetypal K(+) channel KcsA. (nih.gov)
  • By applying the method to potassium channel KcsA at 3.2 A, we obtained a structural model with an improved fit with the diffraction data. (rcsb.org)
  • Our work focuses on voltage-gated potassium channels, which play a key role in many cellular and organismal functions, including signal transmission in our nervous system. (biophysics.org)
  • Due to the importance of potassium channels in cellular function, researchers have been challenged to develop tools and experimental procedures to probe the function and identify chemicals that modulate the behaviour of this super-family of ion channels. (springer.com)
  • Potassium channels, present in the cells of virtually all living organisms, are core components in bioelectricity generation and cellular communication. (uchospitals.edu)
  • One possibility is to issue the channels a ticket straight to the cellular dumpster, discovered researchers at the Salk Institute for Biological Studies. (bio-medicine.org)
  • Ion channels expressed in macrophages have been tightly related to atherosclerosis by coupling cellular function. (sigmaaldrich.com)
  • Potassium channel activator Atten. (mendeley.com)
  • The present invention describes novel nitrosated and/or nitrosylated potassium channel activators, and novel compositions comprising at least one nitrosated and/or nitrosylated potassium channel activator, and, optionally, at least one compound that donates, transfers or releases nitric oxide, elevates. (google.com)
  • The present invention describes novel nitrosated and/or nitrosylated potassium channel activators, and novel compositions comprising at least one nitrosated and/or nitrosylated potassium channel activator, and, optionally, at least one compound that donates, transfers or releases nitric oxide, elevates endogenous levels of endothelium-derived relaxing factor, stimulates endogenous synthesis of nitric oxide or is a substrate for nitric oxide synthase and/or at least one vasoactive agent. (google.com)
  • 2 Primarily on the basis of studies using pharmacological tools, openers of K ATP channels have been shown to elicit cardioprotective effects, whereas K ATP channel antagonists have been shown to block the cardioprotective effects of K ATP channel openers and the powerful protective effect produced by single or multiple brief episodes of ischemia to reduce myocardial infarct size, a phenomenon called ischemic preconditioning. (ahajournals.org)
  • We have made significant progress in identifying novel pharmacological activators of the Slack potassium channel for potential therapeutic intervention in FXS individuals. (fraxa.org)
  • Our current knowledge of the effects of disease on vascular K + channel function almost exclusively relies on interpretation of data obtained by using pharmacological modulators of K + channels. (ahajournals.org)
  • [3] They are the targets of multiple toxins, and malfunction of the channels has been implicated in several diseases. (wikipedia.org)
  • There is no doubt that all these studies on potassium channels as possible pharmaceutical targets will facilitate future translational research. (nih.gov)
  • These cytoplasmic regions are essential for normal channel function and, due to their accessibility to the cytoplasmic environment, constitute obvious targets for cell-physiological control of channel behavior. (frontiersin.org)
  • Kv4.3/KChIP2.2 channels expressed in heart are therapeutic targets in atrial fibrillation. (criver.com)
  • Until recently, the prevailing theory was that either K ATP openers or ischemia resulted in the enhanced shortening of action potential duration (APD), which shortened phases 2 and 3 of the action potential and resulted in a blockade of L-type calcium channels and a reduction in calcium overload during ischemia and/or reperfusion. (ahajournals.org)
  • [3] Glyburide (10-500 nM) produces a dose-dependent inhibition of the potassium channel openers (PCOs) relaxation time course. (selleckchem.com)
  • Drewe JA, Verma S, Frech G, Joho RH (1992) Distinct spatial and temporal expression patterns of K + channel mRNAs from different subfamilies. (springer.com)
  • However, recent studies have revealed that several ion channels of different subfamilies are impacted by SAH and may contribute to delayed vasospasm. (hindawi.com)
  • Overview of the Kv channels subfamilies. (frontiersin.org)
  • Liu W-X, Deng E-Z, Chen W, Lin H. Identifying the Subfamilies of Voltage-Gated Potassium Channels Using Feature Selection Technique. (mdpi.com)
  • This signature sequence is highly conserved, with the exception that a valine residue in prokaryotic potassium channels is often substituted with an isoleucine residue in eukaryotic channels. (wikipedia.org)
  • Cui J, Aldrich RW (2000) Allosteric linkage between voltage and Ca 2+ -dependent activation of BK-type mslo1 K + channels. (springer.com)