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.

Alternative sulfonylurea receptor expression defines metabolic sensitivity of K-ATP channels in dopaminergic midbrain neurons. (1/2415)

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. (2/2415)

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)

Inducible genetic suppression of neuronal excitability. (3/2415)

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)

Glucose-receptive neurones in the rat ventromedial hypothalamus express KATP channels composed of Kir6.1 and SUR1 subunits. (4/2415)

1. Patch-clamp recordings were made from rat ventromedial hypothalamic neurones in slices of brain tissue in vitro. In cell-attached recordings, removal of extracellular glucose or metabolic inhibition with sodium azide reduced the firing rate of a subpopulation of cells through the activation of a 65 pS channel that was blocked by the sulphonylureas tolbutamide and glibenclamide. 2. In whole-cell patch-clamp recordings, in the absence of ATP in the electrode solution, glucose-receptive neurones gradually hyperpolarized due to the induction of an outward current at -60 mV. This outward current and the resultant hyperpolarization were blocked by the sulphonylureas tolbutamide and glibenclamide. 3. In recordings where the electrode solution contained 4 mM ATP, this outward current was not observed. Under these conditions, 500 microM diazoxide was found to induce an outward current that was blocked by tolbutamide. 4. In cell-attached recordings diazoxide and the active fragment of leptin (leptin 22-56) reduced the firing rate of glucose-receptive neurones by the activation of a channel with similar properties to that induced by removal of extracellular glucose. 5. Reverse transcription followed by the polymerase chain reaction using cytoplasm from single glucose-receptive neurones demonstrated the expression of the ATP-sensitive potassium (KATP) channel subunits Kir6.1 and SUR1 but not Kir6.2 or SUR2. 6. It is concluded that glucose-receptive neurones within the rat ventromedial hypothalamus exhibit a KATP channel current with pharmacological and molecular properties similar to those reported in other tissues.  (+info)

Somatostatin induces hyperpolarization in pancreatic islet alpha cells by activating a G protein-gated K+ channel. (5/2415)

Somatostatin inhibits glucagon-secretion from pancreatic alpha cells but its underlying mechanism is unknown. In mouse alpha cells, we found that somatostatin induced prominent hyperpolarization by activating a K+ channel, which was unaffected by tolbutamide but prevented by pre-treating the cells with pertussis toxin. The K+ channel was activated by intracellular GTP (with somatostatin), GTPgammaS or Gbetagamma subunits. It was thus identified as a G protein-gated K+ (K(G)) channel. RT-PCR and immunohistochemical analyses suggested the K(G) channel to be composed of Kir3.2c and Kir3.4. This study identified a novel ionic mechanism involved in somatostatin-inhibition of glucagon-secretion from pancreatic alpha cells.  (+info)

Proadrenomedullin N-terminal 20 peptide hyperpolarizes the membrane by activating an inwardly rectifying K+ current in differentiated PC12 cells. (6/2415)

The mechanism of proadrenomedullin N-terminal 20 peptide (PAMP)-induced inhibition of catecholamine release from adrenergic nerve was investigated in nerve growth factor-treated PC12 cells that have differentiated characteristics somewhat similar to noradrenergic neurons. The effect of PAMP on the excitability of these cells was investigated with the use of perforated whole-cell clamp. PAMP hyperpolarized the membrane by increasing a K+ conductance in a dose-dependent manner. The current-voltage relationship (I-V) relationship of the PAMP-induced K+ conductance exhibited inward-going rectification. The activation was abolished by microinjecting GDPbetaS into the cells or pretreating the cells with pertussis toxin. These results indicate that a pertussis toxin-sensitive G protein is involved in the signal transduction. The PAMP-induced activation of the K+ conductance was attenuated by microinjecting antibody against the carboxyl terminus of Galphai3, but it was not influenced by microinjecting antibody against the common carboxyl termini of Galphai1 and Galphai2, which indicated that the G protein coupling the PAMP receptor to the inwardly rectifying K+ current is Galphai3. The PAMP-induced hyperpolarization may inhibit the catecholamine release from the neurons by attenuating the action potential frequency.  (+info)

Selective activation of heterologously expressed G protein-gated K+ channels by M2 muscarinic receptors in rat sympathetic neurones. (7/2415)

1. G protein-regulated inward rectifier K+ (GIRK) channels were over-expressed in dissociated rat superior cervical sympathetic (SCG) neurones by co-transfecting green fluorescent protein (GFP)-, GIRK1- and GIRK2-expressing plasmids using the biolistic technique. Membrane currents were subsequently recorded with whole-cell patch electrodes. 2. Co-transfected cells had larger Ba2+-sensitive inwardly rectifying currents and 13 mV more negative resting potentials (in 3 mM [K+]o) than non-transfected cells, or cells transfected with GIRK1 or GIRK2 alone. 3. Carbachol (CCh, 1-30 microM) increased the inwardly rectifying current in 70 % of GIRK1+ GIRK2-transfected cells by 261 +/- 53 % (n = 6, CCh 30 microM) at -120 mV, but had no effect in non-transfected cells or in cells transfected with GIRK1 or GIRK2 alone. Pertussis toxin prevented the effect of carbachol but had no effect on basal currents. 4. The effect of CCh was antagonized by 6 nM tripitramine but not by 100 nM pirenzepine, consistent with activation of endogenous M2 muscarinic acetylcholine receptors. 5. In contrast, inhibition of the voltage-activated Ca2+ current by CCh was antagonized by 100 nM pirenzepine but not by 6 nM tripitramine, indicating that it was mediated by M4 muscarinic acetylcholine receptors. 6. We conclude that endogenous M2 and M4 muscarinic receptors selectively couple to GIRK currents and Ca2+ currents respectively, with negligible cross-talk.  (+info)

Kir2.1 encodes the inward rectifier potassium channel in rat arterial smooth muscle cells. (8/2415)

1. The molecular nature of the strong inward rectifier K+ channel in vascular smooth muscle was explored by using isolated cell RT-PCR, cDNA cloning and expression techniques. 2. RT-PCR of RNA from single smooth muscle cells of rat cerebral (basilar), coronary and mesenteric arteries revealed transcripts for Kir2.1. Transcripts for Kir2.2 and Kir2.3 were not found. 3. Quantitative PCR analysis revealed significant differences in transcript levels of Kir2.1 between the different vascular preparations (n = 3; P < 0.05). A two-fold difference was detected between Kir2.1 mRNA and beta-actin mRNA in coronary arteries when compared with relative levels measured in mesenteric and basilar preparations. 4. Kir2.1 was cloned from rat mesenteric vascular smooth muscle cells and expressed in Xenopus oocytes. Currents were strongly inwardly rectifying and selective for K+. 5. The effect of extracellular Ba2+, Ca2+, Mg2+ and Cs2+ ions on cloned Kir2.1 channels expressed in Xenopus oocytes was examined. Ba2+ and Cs+ block were steeply voltage dependent, whereas block by external Ca2+ and Mg2+ exhibited little voltage dependence. The apparent half-block constants and voltage dependences for Ba2+, Cs+, Ca2+ and Mg2+ were very similar for inward rectifier K+ currents from native cells and cloned Kir2.1 channels expressed in oocytes. 6. Molecular studies demonstrate that Kir2.1 is the only member of the Kir2 channel subfamily present in vascular arterial smooth muscle cells. Expression of cloned Kir2.1 in Xenopus oocytes resulted in inward rectifier K+ currents that strongly resemble those that are observed in native vascular arterial smooth muscle cells. We conclude that Kir2.1 encodes for inward rectifier K+ channels in arterial smooth muscle.  (+info)

Inward-rectifier potassium channels (Kir, IRK) are a specific subset of potassium channels. To date, seven subfamilies have been identified in various mammalian cell types, plants, and bacteria. They are the targets of multiple toxins, and malfunction of the channels has been implicated in several diseases. IRK channels possess a pore domain, homologous to that of voltage-gated ion channels, and flanking transmembrane segments (TMSs). They may exist in the membrane as homo- or heterooligomers and each monomer possesses between 2 and 4 TMSs. In terms of function, these proteins transport potassium (K+), with a greater tendency for K+ uptake than K+ export. 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). It is thought that this current may play an important role in regulating neuronal activity, by helping to stabilize the resting membrane potential of the cell. ...
TY - JOUR. T1 - Compound-induced block of ion channel pore function. T2 - Inward-rectifier potassium channels as a model. AU - Furutani, Kazuharu. AU - Hibino, Hiroshi. AU - Inanobe, Atsushi. AU - Kurachi, Yoshihisa. PY - 2009/12/1. Y1 - 2009/12/1. N2 - Small chemical compounds modulate ion channel functions. This is the reflection of ligand interactions with ion channels at their various sites. Many biophysical and biochemical researches have been performed on this subject and have provided important basic concepts on the structure-functional relationships of ion channels. Especially, ion channel blockers have been excellent tools for biophysical studies of ion channels and some of them are actually used for treating various diseases. The mechanisms underlying the blocking action of various chemical compounds, however, remain largely unknown at the atomic level, partly because of the promiscuous nature of the reaction. As one of the attempts to overcome the problem, we have adopted a novel ...
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).
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).
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 ...
Since the mechanism of salt impairing NO-induced vascular relaxation is not fully clear, this study was designed to investigate the role of potassium (K+) channels in the vasodilatory effects of NO donor in salt loaded rats. Isolated thoracic aortic rings of adult male albino rats fed 8% NaCl containing diet for six weeks were used for isometric tension recording using PowerLab tissue bath system. The recorded data revealed that high salt diet (HS) did not change the relaxation responses to sodium nitroprusside (SNP, an NO donor) in rats thoracic aortic rings. SNP-induced relaxation in salt loaded rats was significantly lower in rings contracted by high K+ than phenylephrine (PE, a selective α1-adrenergic receptor agonist). On the other hand, incubation of aortic rings from salt loaded rats with inward-rectifier K+ (KIR) channel blockers either individually or simultaneously with other K+ channel blockers significantly inhibited SNP-induced relaxation in PE-contracted rings; however incubation ...
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). It is thought that this current may play an important role in regulating neuronal activity, by helping to stabilize the resting membrane potential of the cell. By convention, inward current (positive charge moving into the cell) is displayed in voltage clamp as a downward deflection, while an outward current (positive charge moving out of the cell) is shown as an upward deflection. At membrane potentials negative to potassiums 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. This can be seen in figure 1: when the membrane potential is clamped negative to the channels resting potential (e.g. -60 mV), inward current flows (i.e. positive charge flows into the cell). However, when the ...
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). It is thought that this current may play an important role in regulating neuronal activity, by helping to stabilize the resting membrane potential of the cell. By convention, inward current (positive charge moving into the cell) is displayed in voltage clamp as a downward deflection, while an outward current (positive charge moving out of the cell) is shown as an upward deflection. At membrane potentials negative to potassiums 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. This can be seen in figure 1: when the membrane potential is clamped negative to the channels resting potential (e.g. -60 mV), inward current flows (i.e. positive charge flows into the cell). However, when the ...
We demonstrate that tamoxifen, a synthetic nonsteroidal triphenylethylene derivative, which has estrogenic, antiestrogenic effects, 4-hydroxytamoxifen, an active metabolite of tamoxifen, and raloxifene, the selective estrogen receptor modulator used to treat osteoporosis in postmenopausal women, inhibit the strong inward rectifier potassium channels Kir2.x. The order of inhibition for all three drugs was Kir2.3 , Kir2.1 ∼ Kir2.2. The inhibition of Kir2.x current by tamoxifen, 4-hydroxytamoxifen, and raloxifene occurred slowly (T1/2 ∼ 6 min), and the currents only partially recovered after washout (∼30%). Tamoxifen also inhibited IK1 in cat atrial and ventricular myocytes, and the effects were greater in the former than the latter.. The inhibition induced by tamoxifen, 4-hydroxytamoxifen, and raloxifene was concentration-dependent but voltage-independent. The potency of tamoxifen to inhibit Kir2.1 channel was greater than 4-hydroxytamoxifen and raloxifene. The IC50 of inhibition by ...
Heteromultimerization between different potassium channel subunits can generate channels with novel functional properties and thus contributes to the rich functional diversity of this gene family. The inwardly rectifying potassium channel subunit Kir5.1 exhibits highly selective heteromultimerization with Kir4.1 to generate heteromeric Kir4.1/Kir5.1 channels with unique rectification and kinetic properties. These novel channels are also inhibited by intracellular pH within the physiological range and are thought to play a key role in linking K+ and H+ homeostasis by the kidney. However, the mechanisms that control heteromeric K+ channel assembly and the structural elements that generate their unique functional properties are poorly understood. In this study we identify residues at an intersubunit interface between the cytoplasmic domains of Kir5.1 and Kir4.1 that influence the novel rectification and gating properties of heteromeric Kir4.1/Kir5.1 channels and that also contribute to their pH sensitivity
Type 2 diabetes is a polygenic disorder (1). Progress in defining the underlying molecular genetics has been limited. In pancreatic β-cells, ATP-sensitive potassium (KATP) channels control insulin secretion by coupling metabolism to membrane electrical activity. The KATP channel is a complex of two types of essential subunits, the sulfonylurea receptor (SUR1) and the inwardly rectifying potassium channel (Kir6.2) (2).. Mutations in both genes (SUR1, ABCC8; Kir6.2, KCNJ11) cause familial hyperinsulinemia of infancy (HI) (3). Polymorphisms in the genes (ABCC8, exon 16-3t/c, exon 18 C/T, KCNJ11 E23K) have been reported to be associated with type 2 diabetes in several populations, although the data are inconsistent (4-15). Even though there are no data to support a functional role of either of the two ABCC8 variants, a recent study has provided evidence that E23K alters function by inducing spontaneous over-activity of pancreatic β-cells, thus increasing the threshold ATP concentration for insulin ...
ATP-sensitive K+ (K(ATP)) channels are hetero-octamers of inwardly rectifying K+ channel (Kir6.2) and sulphonylurea receptor subunits (SUR1 in pancreatic beta-cells, SUR2A in heart). Heterozygous gain-of-function mutations in Kir6.2 cause neonatal diabetes, which may be accompanied by epilepsy and developmental delay. However, despite the importance of K(ATP) channels in the heart, patients have no obvious cardiac problems. We examined the effects of adenine nucleotides on K(ATP) channels containing wild-type or mutant (Q52R, R201H) Kir6.2 plus either SUR1 or SUR2A. In the absence of Mg2+, both mutations reduced ATP inhibition of SUR1- and SUR2A-containing channels to similar extents, but when Mg2+ was present ATP blocked mutant channels containing SUR1 much less than SUR2A channels. Mg-nucleotide activation of SUR1, but not SUR2A, channels was markedly increased by the R201H mutation. Both mutations also increased resting whole-cell K(ATP) currents through heterozygous SUR1-containing channels to a
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 ...
ATP-sensitive potassium channels (KATP) regulate a range of biological activities by coupling membrane excitability to the cellular metabolic state. In particular, it has been proposed that KATP channels and specifically, the channel subunits Kir6.1 and SUR2B, play an important role in the regulation of vascular tone. However, recent experiments have suggested that KATP channels outside the vascular smooth muscle compartment are the key determinant of the observed behavior. Thus, we address the importance of the vascular smooth muscle KATP channel, using a novel murine model in which it is possible to conditionally delete the Kir6.1 subunit. Using a combination of molecular, electrophysiological, in vitro, and in vivo techniques, we confirmed the absence of Kir6.1 and KATP currents and responses specifically in smooth muscle. Mice with conditional deletion of Kir6.1 showed no obvious arrhythmic phenotype even after provocation with ergonovine. However, these mice were hypertensive and vascular ...
ATP-sensitive K(+) (K(ATP)) channels, comprised of pore-forming Kir6.x and regulatory SURx subunits, play important roles in many cellular functions; because of their sensitivity to inhibition by intracellular ATP, K(ATP) channels provide a link between cell metabolism and membrane electrical activity. We constructed structural homology models of Kir6.2 and a series of Kir6.2 channels carrying mutations within the putative ATP-binding site. Computational docking was carried out to determine the conformation of ATP in its binding site. The Linear Interaction Energy (LIE) method was used to estimate the free-energy of ATP binding to wild-type and mutant Kir6.2 channels. Comparisons of the theoretical binding free energies for ATP with those determined from mutational experiments enabled the identification of the most probable conformation of ATP bound to the Kir6.2 channel. A set of LIE parameters was defined that may enable prediction of the effects of additional Kir6.2 mutations within the ATP binding
Extracellular Zn(2+) has been identified as an activator of pancreatic K(ATP) channels. We further examined the action of Zn(2+) on recombinant K(ATP) channels formed with the inward rectifier K(+) channel subunit Kir6.2 associated with either the pancreatic/neuronal sulphonylurea receptor 1 (SUR1) …
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 …
MS Model, Version 5.0 ********************** //*************************** MScell.p ********************** // Tom Sheehan [email protected] [email protected] 703-538-836 //***************************************************************************** *relative *cartesian *asymmetric *lambda_warn *set_global ELEAK -0.070 //*set_global RA 1.0 //*set_global RM 8.695652 1.8 *set_global RM 2.7 //*set_global CM 0.010 //change Cm to account for no spines - make 3x higher? *set_global CM 0.02 *set_global EREST_ACT -0.085 *start_cell /library/tert_dend tert_dend none 35.927 0 0 0.80 tert_dend2 . 35.927 0 0 0.80 tert_dend3 . 35.927 0 0 0.80 tert_dend4 . 35.927 0 0 0.80 tert_dend5 . 35.927 0 0 0.80 tert_dend6 . 35.927 0 0 0.80 tert_dend7 . 35.927 0 0 0.80 tert_dend8 . 35.927 0 0 0.80 tert_dend9 . 35.927 0 0 0.80 tert_dend10 . 35.927 0 0 0.80 tert_dend11 . 35.927 0 0 0.80 *makeproto /library/tert_dend *start_cell /library/sec_dend sec_dend none 24.230 0 0 1.100 *makeproto /library/sec_dend *start_cell ...
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.
1. ATP-sensitive potassium (KATP) channels are composed of pore-forming Kir6.2 and regulatory SUR subunits. A truncated isoform of Kir6.2, Kir6.2DeltaC26, forms ATP-sensitive channels in the absence of SUR1, suggesting the ATP-inhibitory site lies on Kir6.2. 2. Previous studies have shown that mutation of the lysine residue at position 185 (K185) in the C-terminus of Kir6.2 to glutamine, decreased the channel sensitivity to ATP without affecting the single-channel conductance or the intrinsic channel kinetics. This mutation also impaired 8-azido[32P]-ATP binding to Kir6.2. 3. To determine if K185 interacts directly with ATP, we made a range of mutations at this position, and examined the effect on the channel ATP sensitivity by recording macroscopic currents in membrane patches excised from Xenopus oocytes expressing wild-type or mutant Kir6.2DeltaC26. 4. Substitution of K185 by a positively charged amino acid (arginine) had no substantial effect on the sensitivity of the channel to ATP. Mutation to a
MS Model, Version 5.0 ********************** //*************************** MScell.p ********************** // Tom Sheehan [email protected] [email protected] 703-538-836 //***************************************************************************** *relative *cartesian *asymmetric *lambda_warn *set_global ELEAK -0.070 //*set_global RA 1.0 //*set_global RM 8.695652 1.8 1.83-0.0295 1.86-0.029 1.96-0.0275 2.16-0.025 *set_global RM 1.8 //1.8-0.03 //*set_global CM 0.010 //change Cm to account for no spines - make 3x higher? 0.03 0.025 *set_global CM 0.03 *set_global EREST_ACT -0.085 *start_cell /library/tert_dend tert_dend none 35.927 0 0 0.80 tert_dend2 . 35.927 0 0 0.80 tert_dend3 . 35.927 0 0 0.80 tert_dend4 . 35.927 0 0 0.80 tert_dend5 . 35.927 0 0 0.80 tert_dend6 . 35.927 0 0 0.80 tert_dend7 . 35.927 0 0 0.80 tert_dend8 . 35.927 0 0 0.80 tert_dend9 . 35.927 0 0 0.80 tert_dend10 . 35.927 0 0 0.80 tert_dend11 . 35.927 0 0 0.80 *makeproto /library/tert_dend *start_cell /library/sec_dend sec_dend none ...
from neuron import h import matplotlib.pyplot as plt import numpy as np import seaborn as sns soma = h.Section() dend = h.Section() soma.L = 10 soma.diam = 10 soma.Ra = 1000 soma.insert(pas) soma.g_pas = 1e-5 soma.cm = 1 dend.L = 200 dend.nseg = 47 dend.diam = 3 dend.Ra = 1000 dend.insert(pas) dend.g_pas = 1e-3 dend.cm = 1 dend.connect(soma(0), 0) # dend.connect(soma(0), 1) istim = h.IClamp(1.0, dend) istim.amp = 0.2 istim.delay = 100 istim.dur = 30 vdlist = [] vdlist.append(h.Vector()) vdlist.append(h.Vector()) vdlist.append(h.Vector()) vs = h.Vector() t = h.Vector() vdlist[0].record(dend(1.0)._ref_v) vdlist[1].record(dend(0.5)._ref_v) vdlist[2].record(dend(0.0)._ref_v) vs.record(soma(0.5)._ref_v) t.record(h._ref_t) h.load_file(stdrun.hoc) h.init() h.tstop = 200 h.run() # Plotting code from here rows = 2 fig = plt.figure(); plot_num = 1; ax2 = fig.add_subplot(rows, 1, plot_num); plot_num += 1; ax2.set_ylabel(Vd) ax2.set_xlabel(t) ax2.xaxis.set_ticks(np.arange(0, h.tstop, 10)) ...
Anionic phospholipids (e.g. PIP2) activate all inward rectifier K+ (Kir) channels and degradation of phospholipids by endogenous lipid phosphatases or phospholipases is a well-accepted mechanism for Kir current rundown in excised membrane patches. The rate of Kir current rundown varies and is inversely correlated to the PIP-binding affinity of the channel being studied, with rundown being faster for channels that bind PIPs less strongly [14-16].. Sensitivity of KATP channels to phosphoinositide turnover was first demonstrated in giant membrane patches from cardiac myocytes, where native Kir6.2/SUR2A channels are abundant [17]. These channels run down rapidly in excised patches exposed to nucleotide-free solutions, but following exposure to intracellular MgATP their activity is (at least partially) restored, as seen by comparing the current in control solution before and after ATP application. This increase in channel activity was mimicked by intracellular application of PIP2, and reversed by ...
KATP channels are unique amongst known potassium channels in requiring an unrelated ABC protein subunit (SUR1) in addition to an inward rectifier K channel (Kir6.2) subunit (Inagaki et al., 1995a). In other cloned inward rectifiers, strong inward rectification is controlled by a pore-lining residue in the M2 transmembrane segment (Fakler et al., 1994; Ficker et al., 1994; Lopatin et al., 1994; Lu and MacKinnon, 1994; Stanfield et al., 1994). Mutation of the corresponding residue in Kir6.2 from asparagine to aspartate results in generation of KATP channels that rectify strongly in the presence of cytoplasmic spermine (Fig. 1 b; Clement et al., 1997; Shyng et al., 1997), single channel conductance being unaltered and channels remaining sensitive to inhibition by ATP (Shyng et al., 1997). The requirement for SUR1 to form active channels still raises the possibility that the receptor might also contribute to the pore, and perhaps reduce or otherwise alter the number of Kir6.2 subunits involved. The ...
Kir7.1 is an inwardly rectifying potassium channel that has been implicated in controlling the resting membrane potential of the myometrium. Abnormal uterine activity in pregnancy plays an important role in postpartum hemorrhage, and novel therapies for this condition may lie in manipulation of membrane potential. This work presents an assay development and screening strategy for identifying novel inhibitors of Kir7.1. A cell-based automated patch-clamp electrophysiology assay was developed using the IonWorks Quattro (Molecular Devices, Sunnyvale, CA) system, and the iterative optimization is described. In total, 7087 compounds were tested, with a hit rate (,40% inhibition) of 3.09%. During screening, average Z values of 0.63 ± 0.09 were observed. After chemistry triage, lead compounds were resynthesized and activity confirmed by IC50 determinations. The most potent compound identified (MRT00200769) gave rise to an IC50 of 1.3 µM at Kir7.1. Compounds were assessed for selectivity using the ...
from simpleNrnLib import * def simpleComputational(): dend = make_section(dend) dend.L = 1000 dend.diam = 10 dend.nseg = 21 dend.insert(pas) soma = make_section(soma) soma.L = 1000 soma.diam = 10 soma.nseg = 21 soma.insert(pas) soma.connect(dend,1,0) # connect dend(1) to soma(0) for sec in h.allsec(): sec.Ra = 200 sec.cm = 5.001 for seg in sec: seg.pas.g = 5e-5 seg.pas.e = 0 iClamp = make_iClamp(dend(0)) iClamp.delay = 10 iClamp.amp = 1.2 iClamp.dur = 500000 voltage = h.RangeVarPlot(v) voltage.begin(0) voltage.end(1) tstop = 5000 v_init = -60 h.dt = 0.025 h.finitialize(v_init) h.fcurrent() run(tstop) vVec = h.Vector() pVec = h.Vector() voltage.to_vector(vVec,pVec) return pVec, ...
Inwardly rectifying potassium (Kir) channels form gates in the cell membrane that regulate the flow of K(+) ions into and out of the cell, thereby influencing the membrane potential and electrical signaling of many cell types, including neurons and cardiomyocytes. Kir-channel function depends on other cellular proteins that aid in the folding of channel subunits, assembly into tetrameric complexes, trafficking of quality-controlled channels to the plasma membrane, and regulation of channel activity at the cell surface. We used the yeast Saccharomyces cerevisiae as a model system to identify proteins necessary for the functional expression of a mammalian Kir channel at the cell surface. A screen of 376 yeast strains, each lacking one nonessential protein localized to the early secretory pathway, identified seven deletion strains in which functional expression of the Kir channel at the plasma membrane was impaired. Six deletions were of genes with known functions in trafficking and lipid ...
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In HAECs, the molecular diversity of Kir2 subunits at the transcript level is higher than the diversity of functional Kir. While for Kir2.3 this discrepancy could be explained by undetectable levels of protein expression due to very low transcription, the transcript level of Kir2.4 is similar to that of Kir2.1, suggesting that Kir2.4 functional expression is regulated at a posttranscriptional level. A discrepancy between the heterogeneity of K+ channels at the transcript and functional levels was reported previously for Kir2.x channels in human myoblasts (8) and for voltage-gated K+ channels in rat cardiomyocytes (2, 49), and it has been proposed that translational-posttranslational steps may contribute a rate-limiting step to channel expression (38). Protein expression of Kir2.x subunits in HAECs is consistent with the functional expression of the channels.. The peak IK unitary conductance levels in HAECs (25 and 35 pS) are similar to previously reported values in human umbilical vein ...
HEK293-HuCACNA1C/NEUROD1/CACNA2D1/KCNJ2 cell line is a hypotriploid human cell line, which has been transfected with a human calcium channel, voltage-dependent, L type, alpha 1C subunit (CACNA1C), a human neuronal differentiation 1 (NEUROD1), a human calcium channel, voltage-dependent, alpha 2/delta subunit 1 (CACNA2D1) and a human potassium inwardly-rectifying channel, subfamily J, member 2 (KCNJ2) to allow stably express of the human CACNA1C, NEUROD1, CACNA2D1 and KCNJ2. It is an example of a cell line tr
The present study concludes on the basis of independent kinetic and pharmacological evidence that two components of IK are present in canine atrial and ventricular myocytes. Two tail current components can be distinguished kinetically on the basis of (1) two exponential components describing IK deactivation, (2) differences in the voltage and time dependence of activation of each tail component, and (3) the differential sensitivity of each component to reduced [K+]o. IK components described kinetically (IKe1 and IKe2) were subsequently compared with components identified pharmacologically by using E-4031. The voltage dependence, activation kinetics, and rectification properties of E-4031-sensitive current (typically defined as IKr) were analogous to IKe2 (defined kinetically), whereas E-4031-insensitive current (IKs) was analogous to the more rapid IKe1 in atrial and ventricular myocytes. These similarities argue against the possibility that pharmacologically defined deactivation of IKr is ...
Effects of PPIs on ATP sensitivity at the single-channel level. Single-channel KATP current recorded in an inside-out patch at 0 mV from a rat ventricular cell
Դիգոքսինի ազդեցության հիմնական մեխանիզմը ներառում է սրտամկանում նատրիում/կալիումական ադենոզին եռֆոսֆատազի ( Na + / K + ATPազ) արգելակումը: Այս արգելակումը հանգեցնում է ներբջջային նատրիումի մակարդակի բարձրացմանը, ինչը հետևանք է նատրիումի-կալցիումի փոխարկիչի ակտիվության նվազեցման, որը սովորաբար բջջի մեջ ներմուծում է նատրիումի երեք իոն եւ բջջից դուրս տեղափոխում կալցիումի մեկ իոն: Այս փոխարկիչի անգործությունը առաջացնում է ներբջջային կալցիումի կոնցենտրացիայի ավելացում, որը հասանելի է կծկում առաջացնող սպիտակուցներին: Կալցիումի բարձր մակարդակը ...
Andersen-Tawil Syndrome is a genetic condition that causes periods of muscle weakness (periodic paralysis), changes in heart rhythm (arrhythmia), and intellectual and developmental abnormalities. Other features can include low-set ears, widely spaced eyes, small mandible, fifth-digit clinodactyly, syndactyly, short stature, and scoliosis. Speak to a genetic counselor or a medical geneticist if you have questions about Andersen-Tawil syndrome. ...
TY - JOUR. T1 - Destabilization of ATP-sensitive potassium channel activity by novel KCNJ11 mutations identified in congenital hyperinsulinism. AU - Lin, Yu Wen. AU - Bushman, Jeremy D.. AU - Yan, Fei Fei. AU - Haidar, Sara. AU - MacMullen, Courtney. AU - Ganguly, Arupa. AU - Stanley, Charles A.. AU - Shyng, Show-Ling. PY - 2008/4/4. Y1 - 2008/4/4. N2 - The inwardly rectifying potassium channel Kir6.2 is the pore-forming subunit of the ATP-sensitive potassium (KATP) channel, which controls insulin secretion by coupling glucose metabolism to membrane potential in β-cells. Loss of channel function because of mutations in Kir6.2 or its associated regulatory subunit, sulfonylurea receptor 1, causes congenital hyperinsulinism (CHI), a neonatal disease characterized by persistent insulin secretion despite severe hypoglycemia. Here, we report a novel KATP channel gating defect caused by CHI-associated Kir6.2 mutations at arginine 301 (to cysteine, glycine, histidine, or proline). These mutations in ...
Derst, C.; Wischmeyer, E.; Preisig-Mueller, R.; Spauschus, A.; Konrad, M.; Hensen, P.; Jeck, N.; Seyberth, H. W.; Daut, J.; Karschin, A.: A hyperprostaglandin E syndrome mutation in Kir1.1 (renal outer medullary potassium) channels reveals a crucial residue for channel function in Kir1.3 channels. Journal of Biological Chemistry 273, pp. 23884 - 23891 (1998 ...
Polyamine block of inwardly rectifying potassium (Kir) channels underlies their key functional property of preferential conduction of inward K+ currents (Ficker et al., 1994; Lopatin et al., 1994, 1995; Fakler et al., 1995). As a rapid and voltage-dependent process, polyamine-mediated inward rectification provides a mechanism for moment-to-moment regulation of K+ currents in excitable tissues, shaping both the action potential and resting membrane potential in tissues such as myocardium (Bianchi et al., 1996; Lopatin et al., 2000; Priori et al., 2005; Schulze-Bahr, 2005). Akin to the ongoing challenges to understanding voltage-dependent gating of the Kv channel family, development of a molecular description of steeply voltage-dependent polyamine block is an important issue for understanding the fundamental basis of strongly rectifying Kir channel activity.. Appropriate kinetic models describe polyamine block as a multistep process, incorporating sequentially linked shallow and deep binding ...
Sulfonylureas are widely used to stimulate insulin secretion in type 2 diabetic patients because they close adenosine triphosphate-sensitive potassium (K(ATP)) channels in the pancreatic beta-cell membrane. This action is mediated by binding of the drug to the sulfonylurea receptor (SUR1) subunit of the channel. K(ATP) channels are also present in a range of extrapancreatic tissues, but many of these contain an alternative type of SUR subunit (SUR2A in heart and SUR2B in smooth muscle). The sulfonylurea-sensitivity of K(ATP) channels containing the different types of SUR is variable: gliclazide and tolbutamide block the beta cell, but not the cardiac or smooth muscle types of K(ATP) channels with high affinity. Glibenclamide and glimepiride, on the other hand, block channels containing SUR1 and SUR2 with similar affinity. The reversibility of the different sulfonylureas also varies. Tolbutamide and gliclazide produce a reversible inhibition of Kir6.2/SUR1 and Kir6.2/SUR2 channels, whereas glibenclamide
TY - JOUR. T1 - Fibroblast inward-rectifier potassium current upregulation in profibrillatory atrial Remodeling. AU - Qi, Xiao Yan. AU - Huang, Hai. AU - Ordog, Balazs. AU - Luo, Xiaobin. AU - Naud, Patrice. AU - Sun, Yiguo. AU - Wu, Chia Tung. AU - Dawson, Kristin. AU - Tadevosyan, Artavazd. AU - Chen, Yu. AU - Harada, Masahide. AU - Dobrev, Dobromir. AU - Nattel, Stanley. N1 - Publisher Copyright: © 2015 American Heart Association, Inc. Copyright: Copyright 2015 Elsevier B.V., All rights reserved.. PY - 2015/2/27. Y1 - 2015/2/27. N2 - Rationale: Fibroblasts are involved in cardiac arrhythmogenesis and contribute to the atrial fibrillation substrate in congestive heart failure (CHF) by generating tissue fibrosis. Fibroblasts display robust ion currents, but their functional importance is poorly understood. Objective: To characterize atrial fibroblast inward-rectifier K+ current (IK1) remodeling in CHF and its effects on fibroblast properties. Methods and Results: Freshly isolated left atrial ...
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 ...
Introduction: Andersen-Tawil syndrome (ATS) due to Kir2.1mutations typically manifests as periodic paralysis, cardiac arrhythmias and developmental abnormalities but is often difficult to diagnose clinically. This study was undertaken to determine whether sarcolemmal dysfunction could be identified with muscle velocity recovery cycles (MVRCs). Methods: Eleven genetically confirmed ATS patients and 20 normal controls were studied. MVRCs were recorded with 1, 2, and 5 conditioning stimuli and with single conditioning stimuli during intermittent repetitive stimulation at 20 Hz, in addition to the long exercise test. Results: ATS patients had longer relative refractory periods (P , 0.0001) and less early supernormality, consistent with membrane depolarization. Patients had reduced enhancement of late supernormality with 5 conditioning stimuli (P , 0.0001), and less latency reduction during repetitive stimulation (P , 0.001). Patients were separated completely from controls by combining MVRC and ...
d_iris ,- dist(iris2) # method=man # is a bit better hc_iris ,- hclust(d_iris, method = complete) iris_species ,- rev(levels(iris[,5])) library(dendextend) dend ,- as.dendrogram(hc_iris) # order it the closest we can to the order of the observations: dend ,- rotate(dend, 1:150) # Color the branches based on the clusters: dend ,- color_branches(dend, k=3) #, groupLabels=iris_species) # Manually match the labels, as much as possible, to the real classification of the flowers: labels_colors(dend) ,- rainbow_hcl(3)[sort_levels_values( as.numeric(iris[,5])[order.dendrogram(dend)] )] # We shall add the flower type to the labels: labels(dend) ,- paste(as.character(iris[,5])[order.dendrogram(dend)], (,labels(dend),), sep = ) # We hang the dendrogram a bit: dend ,- hang.dendrogram(dend,hang_height=0.1) # reduce the size of the labels: # dend ,- assign_values_to_leaves_nodePar(dend, 0.5, lab.cex) dend ,- set(dend, labels_cex, 0.5) # And plot: par(mar = c(3,3,3,7)) plot(dend, main = ...
The effects of the cellular environment on innate immunity remain poorly characterized. Here, we show that in Drosophila ATP-sensitive potassium channels (K(ATP)) mediate resistance to a cardiotropic RNA virus, Flock House virus (FHV). FHV viral load in the heart rapidly increases in K(ATP) mutant flies, leading to increased viremia and accelerated death. The effect of K(ATP) channels is dependent on the RNA interference genes Dcr-2, AGO2, and r2d2, indicating that an activity associated with this potassium channel participates in this antiviral pathway in Drosophila. Flies treated with the K(ATP) agonist drug pinacidil are protected against FHV infection, thus demonstrating the importance of this regulation of innate immunity by the cellular environment in the heart. In mice, the Coxsackievirus B3 replicates to higher titers in the hearts of mayday mutant animals, which are deficient in the Kir6.1 subunit of K(ATP) channels, than in controls. Together, our data suggest that K(ATP) channel ...
The inward rectifier K+ channels contain two putative membrane-spanning domains per subunit (M1, M2) and a pore (P) region, which is similar to the H5 domain of voltage-gated K+ channels. Here we have used Fourier transform infrared (FTIR) and CD spectroscopy to analyse the secondary structures of synthetic peptides corresponding to the M1, M2 and P regions of ROMK1 in aqueous solution, in organic solvents and in phospholipid membranes. A previous CD study was unable to provide any structural data on a similar P peptide [Ben-Efraim and Shai (1997) Biophys. J. 72, 85-96]. However, our FTIR and CD spectroscopic analyses indicate that this peptide adopts an α-helical structure when reconstituted into dimyristoyl phosphatidylcholine vesicles and lysophosphatidyl choline (LPC) micelles as well as in trifluoroethanol (TFE) solvent. This result is in good agreement with a previous study on a peptide corresponding to the pore domain of a voltage-gated K+ channel [Haris, Ramesh, Sansom, Kerr, Srai ...
Closure of ATP-regulated K(+) channels (K(ATP) channels) plays a central role in glucose-stimulated insulin secretion in beta cells. K(ATP) channels are also highly expressed in glucagon-producing alpha cells, where their function remains unresolved. Under hypoglycaemic conditions, K(ATP) channels are open in alpha cells but their activity is low and only ~1% of that in beta cells. Like beta cells, alpha cells respond to hyperglycaemia with K(ATP) channel closure, membrane depolarisation and stimulation of action potential firing. Yet, hyperglycaemia reciprocally regulates glucagon (inhibition) and insulin secretion (stimulation). Here we discuss how this conundrum can be resolved and how reduced K(ATP) channel activity, via membrane depolarisation, paradoxically reduces alpha cell Ca(2+) entry and glucagon exocytosis. Finally, we consider whether the glucagon secretory defects associated with diabetes can be attributed to impaired K(ATP) channel regulation and discuss the potential for remedial
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. KCNJ13 has a very low single channel conductance, low sensitivity to block by external barium and cesium, and no dependence of its inward rectification properties on the internal blocking particle magnesium. ...
1N9P: Structural Basis of Inward Rectification: Cytoplasmic Pore of the G Protein-Gated Inward Rectifier GIRK1 at 1.8 A Resolution
The capability of adapting cellular function and energy metabolism to varying physiological and pathological conditions is vitally important in animal cells. In the present work, we show that the Fox family may play a central role in expression of both molecular sensors of energy status and key regulatory genes of energy metabolism. First, in atrial cells, the expression of FoxO1, -O3, and -F2 cause increased expression of KATP channel subunits (the quintessential metabolic sensors7) and selective up- and downregulation of specific metabolic genes. A causal relationship between FoxO and KIR6.1 expression is demonstrated by electrophoretic mobility-shift assay and by experiments with siRNAs. Second, FoxO1, -O3, -F2, and -J2 are distributed unevenly within different cardiac chambers of the neonatal rat, in association with channel subunits KIR6.1, SUR1A, and SUR2B and 9 metabolic genes.42,43,50 Third, the periinfarcted zone of the rat left ventricle reveals an impressive plasticity of FoxO1, -O3, ...
This study is the first to demonstrate the critical role of a dystrophin isoform for the targeting and subcellular distribution of a potassium channel in glial cells. Our immunocytochemical and electrophysiological results demonstrate that functional expression of the dystrophin isoform Dp71 is necessary for the highly asymmetric expression of the inwardly rectifying potassium channel Kir4.1 in the main glial cell type in retina, the Müller cells.. Genetic inactivation of the weakly inwardly rectifying potassium channel Kir4.1 in mice demonstrated that this particular Kir subunit sets the membrane potential in Müller cells and underlies the main potassium conductance in these cells (Kofuji et al., 2000). Such marked asymmetric and clustered distribution of Kir4.1 subunits in these specialized glial cells has presumably the important physiological function of promoting the efficient buffering of extracellular potassium concentration in the retina (Newman et al., 1984). Although the cellular ...
Patients with permanent neonatal diabetes usually present within the first three months of life and need insulin treatment. In most, the cause is unknown. Because ATP-sensitive potassium (KATP) channels mediate glucose-stimulated insulin secretion from the pancreatic beta cells, activating mutations in the gene encoding the Kir6.2 subunit of this channel (KCNJ11) cause neonatal diabetes. Genotyping identifies the exact molecular etiology of early onset insulin requiring diabetes and has the potential to alter the management of the patient, who would otherwise be insulin dependent for life. Method: We identified a 6 year-old child who presented at 3 months of age with diabetic ketoacidosis. Blood samples for molecular genetic analysis were done. Results: The patient was diagnosed as a heterozygous for a missense mutation in the (KCNJ11) gene, for which she switched to sulphonylurea with a dose of 0.05 mg/kg/day. Conclusion: the need for medical practitioners to consider molecular testing for all patients
Predicted to have ATP-activated inward rectifier potassium channel activity. Predicted to be involved in potassium ion import across plasma membrane and regulation of ion transmembrane transport. Predicted to localize to plasma membrane. Used to study hypertrichotic osteochondrodysplasia Cantu type. Orthologous to human KCNJ8 (potassium inwardly rectifying channel subfamily J member 8 ...
Potassium channel openers (KCOs; e.g., P1075, pinacidil) exert their effects on excitable cells by opening ATP-sensitive potassium channels. These channels are heteromultimers composed with a 4:4 stoichiometry of an inwardly rectifying K+ channel subunit plus a regulatory subunit comprising the receptor sites for hypoglycemic sulfonylureas and KCOs (a sulfonylurea receptor). To elucidate stoichiometry of KCO action, we analyzed P1075 sensitivity of channels coassembled from sulfonylurea receptor isoforms with high or low P1075 affinity. Concentration activation curves for cDNA ratios of 1:1 or 1:10 resembled those for channel opening resulting from interaction with a single site, whereas models for activation requiring occupation of two, three, or four sites were incongruous. We conclude KCO-induced channel activation to be mediated by interaction with a single binding site per tetradimeric complex.. ...
Epilepsy, characterized by recurrent seizures, affects 1% of the general population. Interestingly, 25% of diabetics develop seizures with a yet unknown mechanism. Hyperglycemia downregulates inwardly rectifying potassium channel 4.1 (Kir4.1) in cultured astrocytes. Therefore, the present study aims to determine if downregulation of functional astrocytic Kir4.1 channels occurs in brains of type 2 diabetic mice and could influence hippocampal neuronal hyperexcitability. Using whole-cell patch clamp recording in hippocampal brain slices from male mice, we determined the electrophysiological properties of stratum radiatum astrocytes and CA1 pyramidal neurons. In diabetic mice, astrocytic Kir4.1 channels were functionally downregulated as evidenced by multiple characteristics including depolarized membrane potential, reduced barium-sensitive Kir currents and impaired potassium uptake capabilities of hippocampal astrocytes. Furthermore, CA1 pyramidal neurons from diabetic mice displayed increased spontaneous
TY - JOUR. T1 - Investigation of the subunit composition and the pharmacology of the mitochondrial ATP-dependent K+ channel in the brain. AU - Lacza, Zsombor. AU - Snipes, James A.. AU - Kis, Béla. AU - Szabó, Csaba. AU - Grover, Gary. AU - Busija, David W.. PY - 2003/12/19. Y1 - 2003/12/19. N2 - Selective activation of mitoKATP channels can protect the brain or cultured neurons against a variety of anoxic or metabolic challenges. However, little is known about the subunit composition or functional regulation of the channel itself. In the present study, we sought to characterize the mitoKATP channel in the mouse brain using overlapping approaches. First, we determined that mitochondria contain the pore-forming Kir6.1 and Kir6.2 subunits with Western blotting, immunogold electron microscopy and the identification of mitochondrial transport sequences. In contrast, we found no evidence for the presence of either known sulfonylurea receptors (SUR1 or SUR2) in the mitochondria. However, the ...
Context: ATP-sensitive potassium (KATP) stations regulate insulin secretion by coupling glucose rate of metabolism to β-cell membrane potential. gating properties of the producing channels were assessed biochemically and electrophysiologically. Results: Both E208K and V324M augment channel response to MgADP activation without altering level of sensitivity to ATP4? or sulfonylureas. Remarkably whereas E208K causes only a small increase in MgADP response consistent with the slight transient diabetes phenotype V324M causes a severe activating gating defect. Unlike E208K V324M also impairs channel expression in the cell surface which is definitely expected ON-01910 to dampen its practical impact on β-cells. When either mutation was combined with a mutation in the second nucleotide binding website of SUR1 previously shown to abolish Mg-nucleotide response the activating effect of E208K and V324M was also abolished. Moreover combination of E208K and V324M results in channels with Mg-nucleotide level ...
View mouse Kcnj16 Chr11:110968033-111027968 with: phenotypes, sequences, polymorphisms, proteins, references, function, expression
View mouse Kcnj2 Chr11:111066164-111076821 with: phenotypes, sequences, polymorphisms, proteins, references, function, expression
Reaktivität: Fledermaus, Rind (Kuh), Hund and more. 88 verschiedene KCNJ1 Antikörper vergleichen. Alle direkt auf antikörper-online bestellbar!
Opens the Highlight Feature Bar and highlights feature annotations from the FEATURES table of the record. The Highlight Feature Bar can be used to navigate to and highlight other features and provides links to display the highlighted region separately. Links in the FEATURES table will also highlight the corresponding region of the sequence. More... ...
Opens the Highlight Feature Bar and highlights feature annotations from the FEATURES table of the record. The Highlight Feature Bar can be used to navigate to and highlight other features and provides links to display the highlighted region separately. Links in the FEATURES table will also highlight the corresponding region of the sequence. More... ...
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The inwardly rectifying potassium channel, Kir2.3, is a prominent component of the atrial inward rectification mechanism and preferentially localizes to the intercalated disc. The scaffolding protein, synapse associated protein (SAP97), is also found concentrated at the intercalated disk and interacts with Kir channel proteins through the channel proteins c-terminal (CT) residues (SAI). We tested the hypothesis that SAP97 modulates whole-cell Kir2.3 currents by altering one or more biophysical properties of the underlying channel, and that this modulation requires the CT SAI motif.. Methods: Kir2.3 (wtKir2.3 and Kir2.3ΔSAI) and SAP97 were expressed in HEK293 cells singly and in combination. A combination of techniques (cell surface labeling, whole cell and single channel recordings) was used to investigate SAP97 effects Kir2.3 currents.. Results: Co-expression of wtKir2.3/SAP97, but not Kir2.3ΔSAI/SAP97, caused a ~2 fold increase in current density. In the absence of SAP97, Kir2.3 was found ...
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.. ...
The inward rectifying potassium channels of the ROMK family are present in the distal nephron of the kidney. These channels have two membrane spanning portions, between which lies a hydrophobic domain thought to confer the majority of the conductive properties of the channel. The N- and C-termini are both intracellular. In this paper we have examined the contribution of the N- and C-termini to the pore by examining the interaction of Cs|sup|+|/sup| with the channels. ROMK1 has an additional 19 amino acids on its N-terminus in comparison to ROMK2. The C-terminus of ROMK2 was extended by addition of a streptavidin tag (sfROMK2). Currents were measured following expression in Xenopus oocytes using two-electrode voltage clamp. ROMK1, ROMK2 and sfROMK2 exhibited concentration- and voltage-dependent block of inward currents by extracellular Cs|sup|+|/sup|. The Hill coefficients were not significantly different from one. The mean K|sub|d|/sub| values at 0 mV were 100.6 ± 10.6, 63.1 ± 3.9 and 40.6 ± 9.4,
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]. ...
G protein-gated inwardly-rectifying potassium ion channels (GIRK) mediate the postsynaptic inhibitory effect of many neurotransmitters and related drugs of abus...
The place where K and Mg are meeting each other are in the ROMK channel area. Some studies have shown that in the setting of high Mg levels in the cell, the ROMK channel is inhibited and less K is leaked out in the urine. In the setting of low Mg levels, the ROMK channel is more active and more K is leaked out leading to hypokalemia. Another reason that is mentioned is usually in the ascending loop of Henle. The secretion of K channels are ATP dependent( less ATP more open, more ATP less open) and low Mg levels can decrease the amount of ATP production and hence those channels are more open leading to K losses. ...
Neonatal diabetes mellitus is a rare form of monogenic diabetes which is diagnosed in the first 6 months of life. Here we report three patients with neonatal diabetes; two with isolated pancreas agenesis due to mutations in the PTF1A enhancer and one with DEND syndrome (developmental delay, epilepsy, and neonatal diabetes) due to a KCNJ11 mutation. The two cases with mutations in the distal enhacer of PTF1A had a homozygous g.23508363A,G and a homozygous g.23508437A,G mutation respectively. Previous functional analysis showed that these mutations can decrease expression of PTF1A which is involved in pancreas development ...
G protein-coupled inwardly-rectifying potassium channel Inward-rectifier potassium ion channel GRCh38: Ensembl release 89: ... "Entrez Gene: KCNJ6 potassium inwardly-rectifying channel, subfamily J, member 6". Masotti, Andrea; Uva, Paolo; Davis-Keppen, ... Nomenclature and molecular relationships of inwardly rectifying potassium channels". Pharmacol Rev. 57 (4): 509-26. doi:10.1124 ... "G protein-coupled receptors form stable complexes with inwardly rectifying potassium channels and adenylyl cyclase". J. Biol. ...
Isomoto S, Kondo C, Kurachi Y (February 1997). "Inwardly rectifying potassium channels: their molecular heterogeneity and ... Nomenclature and molecular relationships of inwardly rectifying potassium channels". Pharmacological Reviews. 57 (4): 509-26. ... Since all potassium channels share the same ion conducting outer pore structure, Lq2 binds to all three potassium channel types ... It blocks various potassium channels, among others the inward-rectifier potassium ion channel ROMK1. Lq2 is also known as ...
Nomenclature and Molecular Relationships of Inwardly Rectifying Potassium Channels". Pharmacological Reviews. 57 (4): 509-26. ... "Cloning and expression of an inwardly rectifying ATP-regulated potassium channel". Nature. 362 (6415): 31-8. doi:10.1038/ ... 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 ...
Potassium inwardly-rectifying channel, subfamily J, member 16 (KCNJ16) is a human gene encoding the Kir5.1 protein. Potassium ... "Entrez Gene: KCNJ16 potassium inwardly-rectifying channel, subfamily J, member 16". Kubo Y, Adelman JP, Clapham DE, et al. ( ... Nomenclature and molecular relationships of inwardly rectifying potassium channels". Pharmacol. Rev. 57 (4): 509-26. doi: ... Inward-rectifier potassium ion channel GRCh38: Ensembl release 89: ENSG00000153822 - Ensembl, May 2017 GRCm38: Ensembl release ...
Rae JL, Shepard AR (1998). "Inwardly rectifying potassium channels in lens epithelium are from the IRK1 (Kir 2.1) family". Exp ... Dart C, Leyland ML (2001). "Targeting of an A kinase-anchoring protein, AKAP79, to an inwardly rectifying potassium channel, ... Nomenclature and molecular relationships of inwardly rectifying potassium channels". Pharmacol. Rev. 57 (4): 509-26. doi: ... Nomenclature and molecular relationships of inwardly rectifying potassium channels". Pharmacol. Rev. 57 (4): 509-26. doi: ...
Potassium inwardly-rectifying channel, subfamily J, member 14 (KCNJ14), also known as Kir2.4, is a human gene. Potassium ... "Entrez Gene: KCNJ14 potassium inwardly-rectifying channel, subfamily J, member 14". Kubo Y, Adelman JP, Clapham DE, et al. ( ... 2000). "Cloning, structure and assignment to chromosome 19q13 of the human Kir2.4 inwardly rectifying potassium channel gene ( ... Nomenclature and molecular relationships of inwardly rectifying potassium channels". Pharmacol. Rev. 57 (4): 509-26. doi: ...
Potassium inwardly-rectifying channel, subfamily J, member 8, also known as KCNJ8, is a human gene encoding the Kir6.1 protein ... "Entrez Gene: KCNJ8 potassium inwardly-rectifying channel, subfamily J, member 8". Kubo Y, Adelman JP, Clapham DE, et al. (2006 ... Nomenclature and molecular relationships of inwardly rectifying potassium channels". Pharmacol. Rev. 57 (4): 509-526. doi: ... "Mapping of the physical interaction between the intracellular domains of an inwardly rectifying potassium channel, Kir6.2". J. ...
G protein-coupled inwardly-rectifying potassium channel Inward-rectifier potassium ion channel GRCh38: Ensembl release 89: ... "Entrez Gene: KCNJ9 potassium inwardly-rectifying channel, subfamily J, member 9". Jelacic TM, Kennedy ME, Wickman K, Clapham DE ... Plummer HK, Dhar MS, Cekanova M, Schuller HM (2006). "Expression of G-protein inwardly rectifying potassium channels (GIRKs) in ... Nomenclature and molecular relationships of inwardly rectifying potassium channels". Pharmacological Reviews. 57 (4): 509-26. ...
"Entrez Gene: KCNJ11 potassium inwardly-rectifying channel, subfamily J, member 11". Smith AJ, Taneja TK, Mankouri J, ... Nomenclature and molecular relationships of inwardly rectifying potassium channels". Pharmacol. Rev. 57 (4): 509-26. doi: ... "Mapping of the physical interaction between the intracellular domains of an inwardly rectifying potassium channel, Kir6.2". J. ... Inward-rectifier potassium ion channel Potassium channel GRCh38: Ensembl release 89: ENSG00000187486 - Ensembl, May 2017 GRCm38 ...
"Entrez Gene: potassium inwardly-rectifying channel". Foster DB, Ho AS, Rucker J, Garlid AO, Chen L, Sidor A, Garlid KD, ... The renal outer medullary potassium channel (ROMK) is an ATP-dependent potassium channel (Kir1.1) that transports potassium out ... In humans, ROMK is encoded by the KCNJ1 (potassium inwardly-rectifying channel, subfamily J, member 1) gene. Multiple ... Nomenclature and molecular relationships of inwardly rectifying potassium channels". Pharmacological Reviews. 57 (4): 509-26. ...
"Entrez Gene: KCNJ12 potassium inwardly-rectifying channel, subfamily J, member 12". Leonoudakis D, Conti LR, Anderson S, Radeke ... Namba N, Mori R, Tanaka H, Kondo I, Narahara K, Seino Y (1998). "The inwardly rectifying potassium channel subunit Kir2.2v ( ... Nomenclature and molecular relationships of inwardly rectifying potassium channels". Pharmacological Reviews. 57 (4): 509-26. ... "Regulation of cardiac inwardly rectifying potassium current IK1 and Kir2.x channels by endothelin-1". Journal of Molecular ...
Potassium inwardly-rectifying channel, subfamily J, member 15, also known as KCNJ15 is a human gene, which encodes the Kir4.2 ... "Entrez Gene: KCNJ15 potassium inwardly-rectifying channel, subfamily J, member 15". Pearson WL, Dourado M, Schreiber M, Salkoff ... 2007). "Interaction of the Ca2+-sensing receptor with the inwardly rectifying potassium channels Kir4.1 and Kir4.2 results in ... channels reveals a crucial residue for channel function in Kir1.3 channels". J. Biol. Chem. 273 (37): 23884-23891. doi:10.1074/ ...
"Entrez Gene: KCNJ13 potassium inwardly-rectifying channel, subfamily J, member 13". Kubo Y, Adelman JP, Clapham DE, Jan LY, ... Potassium inwardly-rectifying channel, subfamily J, member 13 (KCNJ13) is a human gene encoding the Kir7.1 protein. Inward- ... Nomenclature and molecular relationships of inwardly rectifying potassium channels". Pharmacological Reviews. 57 (4): 509-26. ... "Cloning and characterization of a novel human inwardly rectifying potassium channel predominantly expressed in small intestine ...
G protein-coupled inwardly-rectifying potassium channel Inward-rectifier potassium ion channel GRCh38: Ensembl release 89: ... "Entrez Gene: KCNJ5 potassium inwardly-rectifying channel, subfamily J, member 5". "Gtexportal". GETEX portal. Online Mendelian ... Nomenclature and molecular relationships of inwardly rectifying potassium channels". Pharmacological Reviews. 57 (4): 509-26. ... potassium channel, inwardly rectifying, subfamily j, member 5; KCNJ5 - 600734 Huang CL, Jan YN, Jan LY (April 1997). "Binding ...
A G protein-coupled inwardly-rectifying potassium channel, abbreviated as GIRK. This disambiguation page lists articles ...
Potassium inwardly-rectifying channel, subfamily J, member 4, also known as KCNJ4 or Kir2.3, is a human gene. Several different ... "Entrez Gene: KCNJ4 potassium inwardly-rectifying channel, subfamily J, member 4". Leonoudakis D, Conti LR, Anderson S, Radeke ... The latter are referred to as inwardly rectifying K+ channels, and they have a greater tendency to allow potassium to flow into ... Nomenclature and molecular relationships of inwardly rectifying potassium channels". Pharmacol. Rev. 57 (4): 509-26. doi: ...
"Cloning and expression of an inwardly rectifying ATP-regulated potassium channel". Nature. 362 (6415): 31-8. Bibcode:1993Natur. ... His laboratory identified a potassium excretion regulatory channel involved in Bartter's syndrome type II, two sodium chloride ...
Inwardly rectifying potassium channels have been shown to require docking of PIP2 for channel activity. PtdIns(4,5)P2 has been ... P2 binding sites in Kir2.1 inwardly rectifying potassium channels". FEBS Letters. 490 (1-2): 49-53. doi:10.1016/S0014-5793(01) ... PIP2 regulates the function of many membrane proteins and ion channels, such as the M-channel. The products of the PLC ... One mechanism for direct effect of PtdIns(4,5)P2 is opening of Na+ channels as a minor function in growth hormone release by ...
Examples include coupling to and activating G protein-coupled inwardly-rectifying potassium channels. Small GTPases, also known ... G proteins regulate metabolic enzymes, ion channels, transporter proteins, and other parts of the cell machinery, controlling ...
Isomoto, S; Kondo, C; Kurachi, Y (1997). "Inwardly rectifying potassium channels: their molecular heterogeneity and function". ... The second type of potassium channel that tertiapin blocks is the calcium activated large conductance potassium channel (BK). ... inward rectifier potassium channels (Kir) and calcium activated large conductance potassium channels (BK). Tertiapin is a ... 8 nM for GIRK1/4 channels and Kd = 2 nM for ROMK1 channels. In contrast to the voltage-gated K+ channels, Kir channels are more ...
"Kappa-opioid receptors couple to inwardly rectifying potassium channels when coexpressed by Xenopus oocytes". Molecular ... KORs also couple to inward-rectifier potassium and to N-type calcium ion channels. Recent studies have also demonstrated that ... "Opioid Receptors: κ". IUPHAR Database of Receptors and Ion Channels. International Union of Basic and Clinical Pharmacology. ...
G protein-coupled inwardly-rectifying potassium channel Inward-rectifier potassium ion channel GRCh38: Ensembl release 89: ... Potassium inwardly-rectifying channel, subfamily J, member 3, also known as KCNJ3 or Kir3.1, is a human gene. Potassium ... "Entrez Gene: KCNJ3 potassium inwardly-rectifying channel, subfamily J, member 3". Huang, C L; Jan Y N; Jan L Y (Apr 1997). " ... 1996). "A recombinant inwardly rectifying potassium channel coupled to GTP- binding proteins". J. Gen. Physiol. 107 (3): 381-97 ...
It acts as an inhibitor of G protein-coupled inwardly-rectifying potassium channels (GIRKs). The drug was discovered in the ... "A Novel Antidepressant-like Action of Drugs Possessing GIRK Channel Blocking Action in Rats". Yakugaku Zasshi. 130 (5): 699-705 ... Through inhibition of GIRK channels, tipepidine increases dopamine levels in the nucleus accumbens, but without increasing ... "Tipepidine activates VTA dopamine neuron via inhibiting dopamine D₂ receptor-mediated inward rectifying K⁺ current". ...
Dart C, Leyland ML (2001). "Targeting of an A kinase-anchoring protein, AKAP79, to an inwardly rectifying potassium channel, ...
Embedded in the cell membrane is also the G protein-coupled inwardly-rectifying potassium channel. When a Gβγ or Gα(GTP) ... The activation of the potassium channel and subsequent deactivation of the calcium channel causes membrane hyperpolarization. ... molecule binds to the C-terminus of the potassium channel, it becomes active, and potassium ions are pumped out of the neuron. ... Yamada M, Inanobe A, Kurachi Y (December 1998). "G protein regulation of potassium ion channels". Pharmacological Reviews. 50 ( ...
... a novel inwardly rectifying potassium channel. This protein channel, highly similar to Kir2.2, is transcriptionally regulated ... As the first channel was discovered to cause human disease, this human skeletal muscle sodium channel prevented the muscle from ... In 1991, he discovered that a mutation in a gene (SCN4A) that coded for a muscle cell sodium channel caused the patient's ... Additionally, he has identified other markers of the KCNJ2 channel mutation's including its ECG outputs' T-Wave and U-Wave ...
"Structural mechanism underlying G protein family-specific regulation of G protein-gated inwardly rectifying potassium channel ... able to activate downstream signaling to effectors such as G protein-coupled inwardly-rectifying potassium channels (GIRKs). Gi ...
"Entrez Gene: KCNJ10 potassium inwardly-rectifying channel, subfamily J, member 10". Bockenhauer D, Feather S, Stanescu HC, ... November 1997). "Assignment of the glial inwardly rectifying potassium channel KAB-2/Kir4.1 (Kcnj10) gene to the distal region ... May 1997). "Clustering and enhanced activity of an inwardly rectifying potassium channel, Kir4.1, by an anchoring protein, PSD- ... March 2007). "Interaction of the Ca2+-sensing receptor with the inwardly rectifying potassium channels Kir4.1 and Kir4.2 ...
"Clustering and enhanced activity of an inwardly rectifying potassium channel, Kir4.1, by an anchoring protein, PSD-95/SAP90". ... Kim E, Niethammer M, Rothschild A, Jan YN, Sheng M (Nov 1995). "Clustering of Shaker-type K+ channels by interaction with a ... of the Drosophila discs large tumor suppressor binds to p56lck tyrosine kinase and Shaker type Kv1.3 potassium channel in T ... channel through the GK domain". The EMBO Journal. 19 (1): 78-83. doi:10.1093/emboj/19.1.78. PMC 1171779. PMID 10619846. Adey NB ...
For example, mutations that disrupt an inwardly rectifying potassium channel Kir2.1 cause dominantly inherited Andersen-Tawil ... Dahal, G. R; Rawson, J; Gassaway, B; Kwok, B; Tong, Y; Ptácek, L. J; Bates, E (2012). "An inwardly rectifying K+ channel is ... Mutations that disrupt another inwardly rectifying K+ channel Girk2 encoded by KCNJ6 cause Keppen-Lubinsky syndrome which ... "Keppen-Lubinsky Syndrome is Caused by Mutations in the Inwardly Rectifying K+ Channel Encoded by KCNJ6". The American Journal ...
"Clustering and enhanced activity of an inwardly rectifying potassium channel, Kir4.1, by an anchoring protein, PSD-95/SAP90". ... ligand-gated ion channel activity. • potassium channel regulator activity. • cadherin binding. • Ras guanyl-nucleotide exchange ... regulation of potassium ion import. • regulation of voltage-gated potassium channel activity involved in ventricular cardiac ... ion channel binding. • cytoskeletal protein binding. • protein C-terminus binding. • ionotropic glutamate receptor binding. • ...
... preventing the flux of potassium ions through the channel pore. GluA2-lacking AMPARs are, thus, said to have an inwardly ... rectifying I/V curve, which means that they pass less outward current than inward current at equivalent distance from the ... Ion channel function[edit]. Each AMPAR has four sites to which an agonist (such as glutamate) can bind, one for each subunit.[5 ... The channel opens when two sites are occupied,[17] and increases its current as more binding sites are occupied.[18] Once open ...
... a novel inwardly rectifying potassium channel. This protein channel, highly similar to Kir2.2, is transcriptionally regulated ... As the first channel was discovered to cause human disease, this human skeletal muscle sodium channel prevented the muscle from ... In 1991, he discovered that a mutation in a gene (SCN4A) that coded for a muscle cell sodium channel caused the patient's ... he has identified other markers of the KCNJ2 channel mutation's including its ECG outputs' T-Wave and U-Wave patterns in order ...
Examples include coupling to and activating G protein-coupled inwardly-rectifying potassium channels. ... ion channels, transporter proteins, and other parts of the cell machinery, controlling transcription, motility, contractility, ...
Figure 1. Whole-cell current recordings of Kir2 inwardly-rectifying potassium channels expressed in an HEK293 cell. (This is a ... "Inwardly Recifying Potassium Channels". IUPHAR Database of Receptors and Ion Channels. International Union of Basic and ... At membrane potentials negative to potassium's reversal potential, inwardly rectifying K+ channels support the flow of ... Nomenclature and Molecular Relationships of Inwardly Rectifying Potassium Channels". Pharmacological Reviews. 57 (4): 509-26. ...
... amines depress GABA B response in dopaminergic neurons by inhibiting G-betagamma-gated inwardly rectifying potassium channels ( ...
... including the positively influenced inwardly rectifying potassium channels (=Kir or IRK),[14] and calcium channels, which are ... IN the visual system, cannabinoids agonist induce a dose dependent modulation of calcium, chloride and potassium channels. This ... "IUPHAR Database of Receptors and Ion Channels. International Union of Basic and Clinical Pharmacology. Archived from the ... In summary, CB1 receptor activity has been found to be coupled to certain ion channels, in the following manner:[10] ...
KCNJ2: potassium inwardly-rectifying channel, subfamily J, member 2 (17q24.3). *ACTG1: actin, gamma 1 (17q25) ... TRPV1: encoding protein Transient receptor potential cation channel subfamily V member 1 ... TMC6 and TMC8: Transmembrane channel-like 6 and 8 (epidermodysplasia verruciformis) (17q25.3) ...
... From Wikipedia, the free encyclopedia. (Redirected from Inwardly rectifying potassium ... Figure 1. Whole-cell current recordings of Kir2 inwardly-rectifying potassium channels expressed in an HEK293 cell. (This is a ... "Inwardly Recifying Potassium Channels". IUPHAR Database of Receptors and Ion Channels. International Union of Basic and ... At membrane potentials negative to potassium's reversal potential, inwardly rectifying K+ channels support the flow of ...
... and P/Q-type calcium channels and activate inwardly rectifying potassium channels.[4][11] CB1 antagonists produce inverse ...
... including the positively influenced inwardly rectifying potassium channels (=Kir or IRK),[14] and calcium channels, which are ... chloride and potassium channels. This alters vertical transmission between photoreceptor, bipolar and ganglion cells. Altering ... "IUPHAR Database of Receptors and Ion Channels. International Union of Basic and Clinical Pharmacology. Archived from the ... In summary, CB1 receptor activity has been found to be coupled to certain ion channels, in the following manner:[10] ...
"Muscarine reduces inwardly rectifying potassium conductance in rat nucleus accumbens neurones". The Journal of Physiology. 422 ... In this case, binding of the ligands with the receptor causes an ion channel to open, permitting either one or more specific ... "IUPHAR Database of Receptors and Ion Channels. International Union of Basic and Clinical Pharmacology.. ... By contrast, nicotinic receptors use a ligand-gated ion channel mechanism for signaling. ...
... to reduce the firing rate of neurons through direct activation of G protein-coupled inwardly-rectifying potassium channels.[103 ... tonically activates inwardly rectifying K(+) channels, which reduces the basal firing frequency of dopamine (DA) neurons of the ... San Francisco Meth Zombies (TV documentary). National Geographic Channel. August 2013. ASIN B00EHAOBAO.. ... Because neither of these agonists alone can open this ion channel, glutamate and glycine are referred to as coagonists of the ...
PUBMED - Muscarine reduces inwardly rectifying potassium conductance in rat ... MedlinePlus (enero de 2007). «Oxibutinina». ... and characterization of a unique, potent, peptidyl probe for the high conductance calcium-activated potassium channel from ...
"Inhibition of G-protein-activated inwardly rectifying K+ channels by the selective norepinephrine reuptake inhibitors ... Potassium channel blockers. Hidden categories: *CS1 maint: uses authors parameter. *Drugs with non-standard legal status ...
Embedded in the cell membrane is also the G protein-coupled inwardly-rectifying potassium channel. When a Gβγ or Gα(GTP) ... and potassium ions are pumped out of the neuron.[45] The activation of the potassium channel and subsequent deactivation of the ... Yamada M, Inanobe A, Kurachi Y (December 1998). "G protein regulation of potassium ion channels". Pharmacological Reviews. 50 ( ... molecule binds to the C-terminus of the potassium channel, it becomes active, ...
G protein-coupled inwardly-rectifying potassium channel. *G protein-coupled receptor. *G protein-gated ion channel ...
Endocannabinoids modulate N-type calcium channels and G-protein-coupled inwardly rectifying potassium channels via CB1 ... Co-expression of the voltage-gated potassium channel Kv1.4 with transient receptor potential channels (TRPV1 and TRPV2) and the ... Twitchell W, Brown S, Mackie K , title = Cannabinoids inhibit N- and P/Q-type calcium channels in cultured rat hippocampal ...
... is an inward-rectifier potassium ion channel. Inwardly rectifying potassium channels, such as Kir2.6, maintain resting ... The Kir2.6 also known as inward rectifier potassium channel 18 is a protein that in humans is encoded by the KCNJ18 gene. ... January 2010). "Mutations in potassium channel Kir2.6 cause susceptibility to thyrotoxic hypokalemic periodic paralysis". Cell ...
... including inwardly rectifying K+ channels, ryanodine-inositol 1,4,5-triphosphate receptor Ca2+ channels, transient receptor ... Potassium channels are the largest and most diverse class of voltage-gated channels, with over 100 encoding human genes. These ... Voltage-gated ion-channels are usually ion-specific, and channels specific to sodium (Na+), potassium (K+), calcium (Ca2+), and ... Potassium channels differ in structure from the other channels in that they contain four separate polypeptide subunits, while ...
A Ether-a-go-go potassium channel is a Potassium channel which is Inwardly-rectifying and voltage-gated. Examples include hERG ...
G protein-coupled inwardly-rectifying potassium channels are a type of G protein-gated ion channels because of this direct ... The G protein-coupled inwardly-rectifying potassium channels (GIRKs) are a family of lipid-gated inward-rectifier potassium ion ... G+Protein-Coupled+Inwardly-Rectifying+Potassium+Channels at the US National Library of Medicine Medical Subject Headings (MeSH) ... "The G-protein-gated atrial K+ channel IKACh is a heteromultimer of two inwardly rectifying K+-channel proteins". Nature. 374 ( ...
... effects are a result of the CNO's stimulation and resulting activation of the G-protein inwardly rectifying potassium (GIRK) ... channels. This causes hyperpolarization of the targeted neuronal cell and thus attenuates subsequent activity. This ...
Inward-rectifier potassium channels: These channels allow potassium ions to flow into the cell in an "inwardly rectifying" ... Potassium channels Voltage-gated potassium channels e.g., Kvs, Kirs etc. Calcium-activated potassium channels e.g., BKCa or ... Sodium channels Voltage-gated sodium channels (NaVs) Epithelial sodium channels (ENaCs) Calcium channels (CaVs) Proton channels ... potassium channels are gated by lipids including the inward-rectifier potassium channels and two pore domain potassium channels ...
... inwardly rectifying, Kir (IPR016449) *Inward rectifier potassium channel 13 (IPR008062) *Potassium channel, inwardly rectifying ... Inwardly-rectifying potassium channels (Kir) are the principal class of two-TM domain potassium channels. They are ... Potassium channel, inwardly rectifying, Kir (IPR016449). Short name: K_chnl_inward-rec_Kir ... Inwardly rectifying potassium channels (Kir) are responsible for regulating diverse processes including: cellular excitability ...
Potassium channel, inwardly rectifying, Kir (IPR016449). *Potassium channel, inwardly rectifying, transmembrane domain ( ... Inwardly-rectifying potassium channels (Kir) are the principal class of two-TM domain potassium channels. They are ... Potassium channel, inwardly rectifying, Kir, cytoplasmic (IPR013518). Short name: K_chnl_inward-rec_Kir_cyto ... Inwardly rectifying potassium channels (Kir) are responsible for regulating diverse processes including: cellular excitability ...
Rattus norvegicus potassium inwardly-rectifying channel, subfamily J, member 3 (... Rattus norvegicus potassium inwardly- ... Inwardly rectifying K+ channels Inwardly rectifying K+ channelscomputationally inferred pathway (not manually curated) ... [ ... Rattus norvegicus potassium inwardly-rectifying channel, subfamily J, member 3 (Kcnj3), mRNA. NCBI Reference Sequence: NM_ ... inwardly-rectifying potassium channel; gated by G-protein beta gamma-subunits [RGD, Feb 2006] ...
G protein-coupled inwardly-rectifying potassium channels are a type of G protein-gated ion channels because of this direct ... The G protein-coupled inwardly-rectifying potassium channels (GIRKs) are a family of lipid-gated inward-rectifier potassium ion ... G+Protein-Coupled+Inwardly-Rectifying+Potassium+Channels at the US National Library of Medicine Medical Subject Headings (MeSH) ... "The G-protein-gated atrial K+ channel IKACh is a heteromultimer of two inwardly rectifying K+-channel proteins". Nature. 374 ( ...
Mus musculus potassium inwardly-rectifying channel, subfamily J, member 1 (Kcnj1... Mus musculus potassium inwardly-rectifying ... Inwardly rectifying K+ channels Inwardly rectifying K+ channelscomputationally inferred pathway (not manually curated) ... [ ... Mus musculus potassium inwardly-rectifying channel, subfamily J, member 1 (Kcnj1), transcript variant 1, mRNA. NCBI Reference ... Potassium transport channels Potassium transport channelscomputationally inferred pathway (not manually curated) ... [ ...
We employed a yeast genetic screen to identify functional channels from libraries of K(ir) 2.1 containing mutagenized M1 or M2 ... Inwardly rectifying potassium channels (K(ir)), comprising four subunits each with two transmembrane domains, M1 and M2, ... Transmembrane structure of an inwardly rectifying potassium channel Cell. 1999 Mar 19;96(6):879-91. doi: 10.1016/s0092-8674(00) ... Inwardly rectifying potassium channels (K(ir)), comprising four subunits each with two transmembrane domains, M1 and M2, ...
In the brain inwardly rectifying potassium channel Kir7.1 subunits are predominantly expressed in the choroid plexus and ... Inwardly rectifying K+ channel Kir7.1 is highly expressed in thyroid follicular cells, intestinal epithelial cells and choroid ... Partial gene structure and assignment to chromosome 2q37 of the human inwardly rectifying K+ channel (Kir7.1) gene (KCNJ13). ... Specific localization of an inwardly rectifying K(+) channel, Kir4.1, at the apical membrane of rat gastric parietal cells; its ...
Synonyms: AI842722, ATP-sensitive inward rectifier potassium channel 11, AW491124, Inward rectifier K(+) channel Kir6.2, Kir6.2 ... Protective role of ATP-sensitive potassium channels in hypoxia-induced generalized seizure. Yamada, K., Ji, J.J., Yuan, H., ... ATP-sensitive K+ channels in the hypothalamus are essential for the maintenance of glucose homeostasis. Miki, T., Liss, B., ... ATP-sensitive K+ channel knockout compromises the metabolic benefit of exercise training, resulting in cardiac deficits. Kane, ...
Rapid Activation of Inwardly Rectifying Potassium Channels by Immobile G-Protein-Coupled Receptors. Robert M. Lober, Miguel A. ... 2002) G protein-coupled receptors form stable complexes with inwardly rectifying potassium channels and adenylyl cyclase. J ... Rapid Activation of Inwardly Rectifying Potassium Channels by Immobile G-Protein-Coupled Receptors ... Rapid Activation of Inwardly Rectifying Potassium Channels by Immobile G-Protein-Coupled Receptors ...
J:51106 Mouri T, et al., Assignment of mouse inwardly rectifying potassium channel Kcnj16 to the distal region of mouse ... inwardly rectifying, Kir. IPR008061 Potassium channel, inwardly rectifying, Kir5. IPR013518 Potassium channel, inwardly ... KCNJ16, potassium voltage-gated channel subfamily J member 16. Orthology source: HomoloGene, HGNC ...
IPR013518 Potassium channel, inwardly rectifying, Kir, cytoplasmic. IPR013673 Potassium channel, inwardly rectifying, Kir, N- ... IPR016449 Potassium channel, inwardly rectifying, Kir. IPR003271 Potassium channel, inwardly rectifying, Kir2.1 ... J:4135 Kubo Y, et al., Primary structure and functional expression of a mouse inward rectifier potassium channel [see comments ... KCNJ2, potassium voltage-gated channel subfamily J member 2. Orthology source: HomoloGene, HGNC ...
... potassium inwardly rectifying channel subfamily J member 5), Authors: Dessen P. Published in: Atlas Genet Cytogenet Oncol ... inward rectifier potassium channel activity inward rectifier potassium channel activity protein binding plasma membrane ... inward rectifier potassium channel activity inward rectifier potassium channel activity protein binding plasma membrane ... inward rectifier potassium channel activity T-tubule regulation of ion transmembrane transport voltage-gated potassium channel ...
... potassium inwardly rectifying channel subfamily J member 18), Authors: Dessen P. Published in: Atlas Genet Cytogenet Oncol ... inward rectifier potassium channel activity inward rectifier potassium channel activity inward rectifier potassium channel ... inward rectifier potassium channel activity inward rectifier potassium channel activity inward rectifier potassium channel ... activity plasma membrane integral component of membrane regulation of ion transmembrane transport potassium ion import across ...
... inward rectifier potassium channel activity, potassium ion import across plasma membrane ... Potassium channel, inwardly rectifying subfamily J, member 11Imported. ,p>Information which has been imported from another ... tr,F7D6C0,F7D6C0_XENTR Potassium channel, inwardly rectifying subfamily J, member 11 OS=Xenopus tropicalis OX=8364 GN=kcnj11 PE ... inward rectifier potassium channel activity Source: GO_CentralInferred from biological aspect of ancestori*. "Phylogenetic- ...
... inwardly rectifying K+ channel , potassium channel, inwardly rectifying subfamily J member 1 , potassium inwardly-rectifying ... Potassium inwardly-rectifying channel subfamily J , kir1.1 , inwardly rectifying potassium channel ROMK-2 , potassium inwardly- ... anti-Potassium Inwardly-Rectifying Channel, Subfamily J, Member 10 Antikörper * anti-Potassium Inwardly-Rectifying Channel, ... anti-Potassium Inwardly-Rectifying Channel, Subfamily J, Member 12 Antikörper * anti-Potassium Inwardly-Rectifying Channel, ...
... a strong inwardly rectifying K+ channel of 105 pS (with 140 mm Ko+), an intermediate inwardly rectifying K+ channel of 60 pS, ... Inwardly rectifying potassium (K+) channels (Kir) in Müller cells, the dominant glial cells in the retina, are supposed to be ... Expression and Clustered Distribution of an Inwardly Rectifying Potassium Channel, KAB-2/Kir4.1, on Mammalian Retinal Müller ... 1997) Clustering and enhanced activity of an inwardly rectifying potassium channel, Kir4.1, by an anchoring protein, PSD-95/ ...
Here we have cloned the rat homologue of Kir4.2 and a new isoform of an inwardly rectifying potassium channel (Kir4.2a) from ... Cloning, expression, and localization of a rat hepatocyte inwardly rectifying potassium channel. Ceredwyn E. Hill, M. Martha ... 2000) pH dependence of the inwardly rectifying potassium channel, Kir5.1, and localization in renal tubular epithelia. J Biol ... Two transcripts resembling the Kir4.2 subclass of inwardly rectifying potassium channels were found. The longer deduced isoform ...
... channels underlies their steep voltage--dependence observed in native cells. The structural determinants of polyamine blockade ... Kurata H.T., Cheng W.W.L., Nichols C.G. (2011) Polyamine Block of Inwardly Rectifying Potassium Channels. In: Pegg A., Casero, ... Polyamine blockade of inwardly rectifying potassium (Kir) channels underlies their steep voltage--dependence observed in native ... Cheng WW, Enkvetchakul D, Nichols CG (2009) KirBac1.1: its an inward rectifying potassium channel. J Gen Physiol 133:295-305 ...
For blockade of Kir4.1 channels, we tested several antidepressant agents which reportedly bound to and blocked Kir4.1 channels ... For blockade of Kir4.1 channels, we tested several antidepressant agents which reportedly bound to and blocked Kir4.1 channels ... 4.1 channels in astrocytes regulate neuronal excitability by mediating spatial potassium buffering. Although dysfunction of ... 4.1 channels in astrocytes regulate neuronal excitability by mediating spatial potassium buffering. Although dysfunction of ...
Unconventional role of the inwardly rectifying potassium channel Kir2.2 as a constitutive activator of RelA in cancer. Inkyoung ... Unconventional role of the inwardly rectifying potassium channel Kir2.2 as a constitutive activator of RelA in cancer ... Unconventional role of the inwardly rectifying potassium channel Kir2.2 as a constitutive activator of RelA in cancer ... Unconventional role of the inwardly rectifying potassium channel Kir2.2 as a constitutive activator of RelA in cancer ...
Looking for abbreviations of IRPC? It is Inwardly rectifying potassium channel. Inwardly rectifying potassium channel listed as ... Inwardly rectifying potassium channel - How is Inwardly rectifying potassium channel abbreviated? https://acronyms. ... and four subunits of inwardly rectifying potassium channel ([K.. Potassium channels in health, disease & development of channel ... redirected from Inwardly rectifying potassium channel) Acronym. Definition. IRPC. Immigration Reception and Processing Centre ( ...
Potassium Channels as Targets for Ethanol: Studies of G-Protein-Coupled Inwardly Rectifying Potassium Channel 2 (GIRK2) Null ... Potassium Channels as Targets for Ethanol: Studies of G-Protein-Coupled Inwardly Rectifying Potassium Channel 2 (GIRK2) Null ... Potassium Channels as Targets for Ethanol: Studies of G-Protein-Coupled Inwardly Rectifying Potassium Channel 2 (GIRK2) Null ... Potassium Channels as Targets for Ethanol: Studies of G-Protein-Coupled Inwardly Rectifying Potassium Channel 2 (GIRK2) Null ...
high potassium. GIRK. G protein-coupled inwardly rectifying potassium. G protein. guanine nucleotide binding protein. GPCR. G ... Cannabinoid Receptors Can Activate and Inhibit G Protein-Coupled Inwardly Rectifying Potassium Channels in a Xenopus Oocyte ... Cannabinoid Receptors Can Activate and Inhibit G Protein-Coupled Inwardly Rectifying Potassium Channels in a Xenopus Oocyte ... Cannabinoid Receptors Can Activate and Inhibit G Protein-Coupled Inwardly Rectifying Potassium Channels in a Xenopus Oocyte ...
anti-Potassium Inwardly-Rectifying Channel, Subfamily J, Member 11 (KCNJ11) antibody (Alexa Fluor 488) ABIN903742 from ... anti-Potassium Inwardly-Rectifying Channel, Subfamily J, Member 11 (KCNJ11) antibody (Alexa Fluor 488) from antibodies-online. ... Itemanti-Potassium Inwardly-Rectifying Channel, Subfamily J, Member 11 (KCNJ11) antibody (Alexa Fluor 488) ...
Knockdown of Inwardly Rectifying Potassium Channel Kir2.2 Suppresses Tumorigenesis by Inducing Reactive Oxygen Species-Mediated ... Knockdown of Inwardly Rectifying Potassium Channel Kir2.2 Suppresses Tumorigenesis by Inducing Reactive Oxygen Species-Mediated ... Knockdown of Inwardly Rectifying Potassium Channel Kir2.2 Suppresses Tumorigenesis by Inducing Reactive Oxygen Species-Mediated ... Knockdown of Inwardly Rectifying Potassium Channel Kir2.2 Suppresses Tumorigenesis by Inducing Reactive Oxygen Species-Mediated ...
Potassium Inwardly-Rectifying Channel, Subfamily J, Member 11 antibody for Immunocytochemistry (ICC). ... anti-Potassium Inwardly-Rectifying Channel, Subfamily J, Member 11 Antibodies * anti-Pig (Porcine) Potassium Inwardly- ... Potassium Inwardly-Rectifying Channel, Subfamily J, Member 11 (KCNJ11) Antibodies show synonyms for this antigen * kir6.2 ... Potassium Inwardly-Rectifying Channel, Subfamily J, Member 11 (KCNJ11) Alternative Name KCNJ11 / Kir6.2 (KCNJ11 Antibody ...
This thesis explored this concept through examination of KIR channels in mouse and rat cerebral vascular smooth muscle (VSM). ... Syntrophin and caveolin-1, protein intermediates known to facilitate actin-channel interactions, were both identified in VSM ... and associated mechanotransduction complex of KIR channels in VSM. ... inwardly rectifying potassium channels (KIR) contribute to smooth muscle hyperpolarization to control arterial diameter and ...
... an important role for the regulation of the bee antiviral immune response by ATP-sensitive inwardly rectifying potassium (KATP ... channels. We have shown that treatment with the KATP channel agonist pinacidil increases survival of bees while decreasing ... Our results suggest that KATP channels provide a significant link between cellular metabolism and the antiviral immune response ... viral replication following infection with FHV, whereas treatment with the KATP channel antagonist tolbutamide decreases ...
Potassium Inwardly-Rectifying Channel, Subfamily J, Member 11 antibody for Western Blotting (WB). ... anti-Potassium Inwardly-Rectifying Channel, Subfamily J, Member 11 Antibodies * anti-Rat (Rattus) Potassium Inwardly-Rectifying ... Potassium Inwardly-Rectifying Channel, Subfamily J, Member 11 (KCNJ11) Antibodies show synonyms for this antigen * kir6.2 ... Recommended Potassium Inwardly-Rectifying Channel, Subfamily J, Member 11 Antibody (supplied by: Log in to see ) ...
An inwardly rectifying potassium channel (Kir) is a kind of protein complex that is widely expressed on excitable and ... This review provides insight into Kir channel regulation.. キーワード: Inwardly rectifying potassium channel, Kir, structure, ... Review on Regulation of Inwardly Rectifying Potassium Channels. Junshuai Wang Tongji Hospital of Wuhan ... An inwardly rectifying potassium channel (Kir) is a kind of protein complex that is widely expressed on excitable and ...
  • All K + channels discovered so far possess a core of alpha subunits, each comprising either one or two copies of a highly conserved pore loop domain (P-domain). (ebi.ac.uk)
  • K + channel subunits containing one pore domain can be assigned into one of two superfamilies: those that possess six transmembrane (TM) domains and those that possess only two TM domains. (ebi.ac.uk)
  • In addition, there are K + channel alpha-subunits that possess two P-domains. (ebi.ac.uk)
  • G protein-coupled inwardly-rectifying potassium channels are a type of G protein-gated ion channels because of this direct interaction of G protein subunits with GIRK channels. (wikipedia.org)
  • These are called muscarinic potassium channels (IKACh) and are heterotetramers composed of two GIRK1 and two GIRK4 subunits. (wikipedia.org)
  • Inwardly rectifying potassium channels (K(ir)), comprising four subunits each with two transmembrane domains, M1 and M2, regulate many important physiological processes. (nih.gov)
  • ATP] channel present in the pancreatic [beta] cells is an octamer composed of four subunits of sulphonylurea receptor (SUR1) and four subunits of inwardly rectifying potassium channel ([K. (thefreedictionary.com)
  • In vivo, functional Kir channels are composed of four such subunits which are either homo- or heterotetramers. (elsevier.com)
  • Conclusions: G protein-coupled inwardly rectifying potassium channels, especially those composed of GIRK2 subunits, were inhibited by clinical concentrations of volatile anesthetics. (edu.au)
  • G Protein-Coupled Inwardly-Rectifying Potassium Channels are primarily activated by the complex of GTP-binding protein beta subunits and GTP-binding protein gamma subunits. (wellnessadvocate.com)
  • 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)
  • The genes ABCC8 and KCNJ11, which encode the subunits sulfonylurea receptor 1 (SUR1) and inwardly rectifying potassium channel (Kir6.2) of the β-cell ATP-sensitive potassium (K ATP ) channel, control insulin secretion. (diabetesjournals.org)
  • The K ATP channel is a complex of two types of essential subunits, the sulfonylurea receptor (SUR1) and the inwardly rectifying potassium channel (Kir6.2) ( 2 ). (diabetesjournals.org)
  • Channel subunits are comprised of two transmembrane domains (M1 and M2) flanking a central pore domain (P), which is highly conserved among the great variety of K + channels. (biologists.org)
  • Additionally, weakly rectifying K + currents have been identified in isolated rat and chick hepatocytes ( 12 ), and a Kir4.2 has been cloned from whole mouse liver ( 22 ). (physiology.org)
  • 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)
  • 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)
  • 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)
  • In diabetic mice, astrocytic Kir4.1 channels were functionally downregulated as evidenced by multiple characteristics including depolarized membrane potential, reduced barium-sensitive Kir currents and impaired potassium uptake capabilities of hippocampal astrocytes. (mdpi.com)
  • In Xenopus oocytes , AmqKirA and AmqKirB produced K + currents with strong inward rectification, as seen in the mammalian Kir2 channels, which are found in excitable cells. (biologists.org)
  • channel opener, on ionic currents were examined in rabbit femoral arterial myocytes (RFAMs). (nii.ac.jp)
  • channel currents. (nii.ac.jp)
  • In terms of function, the inhibition of intracellular cAMP expression shortens the duration of pre-synaptic action potentials by prolonging the rectifying potassium A-type currents, which is normally inactivated upon phosphorylation by PKA. (wikipedia.org)
  • Finally, the Gβγ dimeric protein interacts with GIRK channels to open them so that they become permeable to potassium ions, resulting in hyperpolarization of the cell membrane. (wikipedia.org)
  • Inwardly rectifying potassium (K + ) channels (Kir) in Müller cells, the dominant glial cells in the retina, are supposed to be responsible for the spatial buffering action of K + ions. (jneurosci.org)
  • Neural excitation causes an increase of extracellular potassium ions (K + ) especially at synaptic sites in the CNS, including the retina, which if uncorrected would result in the loss of synaptic transmission by depolarizing the membrane. (jneurosci.org)
  • Other factors like polyamines, kinases, pH, and Na + ions act cooperatively to modulate Kir channels. (begellhouse.com)
  • Kir channel activity can be modulated by ions, phospholipids, and binding proteins. (elsevier.com)
  • Members of this family form ion channel pores that allow potassium ions to pass into a cell. (genecards.org)
  • 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)
  • These channels, which transport positively charged atoms (ions) of potassium into and out of cells, play a key role in a cell's ability to generate and transmit electrical signals. (medlineplus.gov)
  • In particular, the transport of potassium ions by ROMK is necessary for the normal function of another ion transporter called NKCC2 (which is produced from the SLC12A1 gene). (medlineplus.gov)
  • These mutations prevent the protein from reaching the cell membrane or alter the channel's ability to transport potassium ions. (medlineplus.gov)
  • The abnormal salt loss disrupts the normal balance of sodium, potassium, and other ions in the body. (medlineplus.gov)
  • Inward rectifier potassium (Kir) channels regulate cell excitability and transport K+ ions across membranes. (ox.ac.uk)
  • In our body's cells, Inwardly Rectifying Potassium Channels , aka Potassium voltage-gated channel subfamily J (KCNJ) , are potassium channels where the flow of K+ ions into the cell is greater than the flow outward. (wellnessadvocate.com)
  • PIP2 activates the ion channel and helps it stay open, which allows ions to flow across the cell membrane. (medlineplus.gov)
  • Some mutations change the shape of the channel so it cannot transport potassium ions, while other mutations prevent the channels from being inserted correctly into the cell membrane. (medlineplus.gov)
  • If the KCNJ2 protein is unable to bind to PIP2, the channels remain closed and potassium ions are unable to flow across the cell membrane. (medlineplus.gov)
  • A loss of this channel's function in skeletal and cardiac muscle cells disrupts the normal flow of potassium ions out of these cells, resulting in periodic paralysis and an irregular heart rhythm. (medlineplus.gov)
  • As a result, more potassium ions flow out of cardiac muscle cells at a critical time during the heartbeat, which can lead to an irregular heart rhythm. (medlineplus.gov)
  • The uptake of potassium ions (K + ) accompanied by an acidification of the apoplasm is a prerequisite for stomatal opening. (portlandpress.com)
  • Recent discovery of a novel mutation in the KCNJ18 gene, which codes for an inwardly rectifying potassium channel and is controlled by thyroid hormones, promotes greater influx of potassium into the cells. (thefreedictionary.com)
  • Gene targeting and genetic analysis have linked Kir channel dysfunction to diverse pathologies. (elsevier.com)
  • Th KCNJ10 gene encodes a member of the inward rectifier-type potassium channel family. (moldiag.com)
  • Compounds were assessed for selectivity using the inwardly rectifying potassium channel Kir1.1 (ROMK) and hERG (human Ether-à-go-go Related Gene). (warwick.ac.uk)
  • 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)
  • Voltage-gated potassium (K V ) channels, first identified as the gene encoding the Shaker mutation in the fruit fly Drosophila , exemplify the second structural architecture in the ion channel superfamily. (aspetjournals.org)
  • This gene encodes a member of the inwardly rectifying potassium channel family of proteins. (genecards.org)
  • KCNJ13 (Potassium Inwardly Rectifying Channel Subfamily J Member 13) is a Protein Coding gene. (genecards.org)
  • Gene Ontology (GO) annotations related to this gene include inward rectifier potassium channel activity . (genecards.org)
  • The protein encoded by this gene is an integral membrane protein and inward-rectifier type potassium channel. (genecards.org)
  • The KCNJ1 gene belongs to a large family of genes that produce potassium channels. (medlineplus.gov)
  • Mutations in the ROMK gene in antenatal Bartter syndrome are associated with impaired K+ channel function. (medlineplus.gov)
  • The gene encoding the inwardly rectifying potassium channel Kir4.1 may be involved in sudden infant death syndrome. (cdc.gov)
  • The KCNJ2 gene belongs to a large family of genes that provide instructions for making potassium channels. (medlineplus.gov)
  • Mutations in the KCNJ2 gene lead to the production of a nonfunctional potassium channel. (medlineplus.gov)
  • 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)
  • These are all highly similar proteins, with only small amino acid changes causing the diversity of the voltage-dependent gating mechanism, channel conductance and toxin binding properties. (ebi.ac.uk)
  • Cloned Kir channel cDNAs encode proteins of between ~370-500 residues, both N- and C-termini are thought to be cytoplasmic, and the N terminus lacks a signal sequence. (ebi.ac.uk)
  • However, other results showed an inhibitory effect of halothane on Gi proteins in human myocardium (24) and supportive research further revealed that volatile anaesthetics including halothane, isoflurane and enflurane in clinical concentrations may also inhibit G protein-coupled inwardly rectifying potassium channels (25). (thefreedictionary.com)
  • and 3) activation of heterotrimeric G-proteins results in inhibition of voltage-gated Ca 2+ channels and subsequently the release of GABA or glutamate. (aspetjournals.org)
  • The functional elements of the ion channel superfamily of proteins can be divided into three complementary aspects: ion conductance, pore gating, and regulation. (aspetjournals.org)
  • The encoded protein belongs to a subfamily of low signal channel conductance proteins that have a low dependence on potassium concentration. (genecards.org)
  • In terms of function, these proteins transport potassium (K + ) , with a greater tendency for K + uptake than K + export. (wikipedia.org)
  • Astrocytic endfeet, lining the bloodbrain barrier (BBB), are enriched in two proteins, aquaporin-4 (AQP4) and inwardly rectifying potassium channel (Kir) 4.1. (ac.rs)
  • In the second part of the book, examples of cholesterol binding sites and consequences of specific cholesterol recognition for protein function are presented for G protein-coupled receptors, ion channels and cholesterol-transporting proteins. (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)
  • The molecular properties and subcellular localization of Müller cell Kir channels in rat and rabbit retinas were examined by using electrophysiological, molecular biological, and immunostaining techniques. (jneurosci.org)
  • Nichols CG (2006) KATP channels as molecular sensors of cellular metabolism. (springer.com)
  • Our first study utilized a genetic knockout mouse model to investigate both the role and molecular composition of vascular K IR channels. (uwo.ca)
  • This mutant fly has led us to our subsequent molecular studies of potassium channels. (mysciencework.com)
  • 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)
  • Here we suggest a molecular mechanism for electromechanical coupling and gating polarity in non-domain-swapped K v channels on the basis of the cryo-electron microscopy structure of KAT1, the hyperpolarization-activated K v channel from Arabidopsis thaliana . (nature.com)
  • Molecular coupling between voltage sensor and pore opening in the Arabidopsis inward rectifier K + channel KAT1. (nature.com)
  • Here we review the molecular and evolutionary relationships among the families within the voltage-gated-like (VGL 1 ) ion channel superfamily. (aspetjournals.org)
  • Molecular dynamics simulations of inwardly rectifying (Kir) potassium channels: a comparative study. (ox.ac.uk)
  • This article identifies all of the members of this protein superfamily in the human genome, reviews the molecular and evolutionary relations among these ion channels, and describes their functional roles in cell physiology. (sciencemag.org)
  • We demonstrate that the plasma membrane phospholipid, PIP 2 , is fundamental to sustaining the activity of inwardly rectifying potassium channels-the molecular feature that allows capillary endothelial cells to sense ongoing neuronal activity and trigger an increase in local blood flow. (pnas.org)
  • The molecular cornerstone of this mechanism is the capillary endothelial cell inward rectifier K + (Kir2.1) channel, which is activated by neuronal activity-dependent increases in external K + concentration, producing a propagating hyperpolarizing electrical signal that dilates upstream arterioles. (pnas.org)
  • abstract = "Inwardly rectifying K+ (Kir) channels allow K+ to move more easily into rather than out of the cell. (elsevier.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)
  • 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)
  • Kir channels serve important roles in cellular physiology such as cell excitability and K + homeostasis. (begellhouse.com)
  • The inward rectifier potassium (Kir) channels play key roles in the physiology of mosquitoes and other insects. (mdpi.com)
  • We present an original analysis of sponge ion channel physiology and an examination of the phylogenetic relationships of this channel with other cloned Kir channels. (biologists.org)
  • and (c) a direct TA1 receptor-mediated activation of GIRK channels which produce cell membrane hyperpolarization. (wikipedia.org)
  • μ-Opioid receptors (MORs) were immobilized on the surface of cerebellar granule neurons by avidin-mediated cross-linking, and inwardly rectifying potassium (GIRK) channels were used as rapid indicators of G-protein activation. (jneurosci.org)
  • Mobile and immobile MORs activated GIRK channels with the same onset kinetics and agonist sensitivity in these neurons. (jneurosci.org)
  • In addition, channel activation could be reconstituted with immobile GPCRs, G-protein heterotrimers, and GIRK channels. (jneurosci.org)
  • Immobilization of GPCRs in neurons had no effect on the speed or sensitivity of responses mediated by inwardly rectifying potassium (GIRK) channels, suggesting that signaling in this system is not limited by receptor diffusion. (jneurosci.org)
  • Finally, immobile GIRK channels could be activated by immobile receptors and G-protein heterotrimers. (jneurosci.org)
  • We proposed that specific behavioral actions of ethanol are due to activation of GIRK channels and that these behaviors would be reduced or eliminated in GIRK2 null mutant ("knockout") mice. (aspetjournals.org)
  • In this study, we focused on the pharmacological characterization of cannabinoid receptor coupling to G protein-gated inwardly rectifying potassium (GIRK) channels. (aspetjournals.org)
  • Furthermore, a conserved aspartate residue in the CB 1 receptor is required for normal communication with GIRK channels in oocytes demonstrating the interaction between receptor and channels is G protein dependent. (aspetjournals.org)
  • All three endocannabinoids activated G-protein-coupled inwardly rectifying potassium (GIRK) channels, GIRK1/4, heterologously expressed in sympathetic neurons. (aspetjournals.org)
  • We wanted to determine if GIRK channels were expressed in lung cancers and if a similar link exists in lung cancer. (biomedcentral.com)
  • We feel these may be important regulatory pathways since no expression of mRNA of the GIRK channels (1 & 2) was found in hamster pulmonary neuroendocrine cells, a suggested cell of origin for SCLC, nor was GIRK1 or 2 expression found in human small airway epithelial cells. (biomedcentral.com)
  • Stimulation of GIRK channels and β-adrenergic signaling may activate similar signaling pathways in both SCLC and breast cancer, but lead to different results. (biomedcentral.com)
  • G protein-gated inwardly rectifying potassium (GIRK) channels play a primary role in the antinociceptive effect of oxycodone, but not morphine, at supraspinal sites. (painresearchforum.org)
  • In contrast, G protein-coupled inwardly rectifying potassium (GIRK) channels were inhibited by volatile anesthetics but not by intravenous anesthetics. (edu.au)
  • Nitrous oxide (∼0.6 atmosphere) slightly but selectively potentiated GIRK channels. (edu.au)
  • Results of chimeric and multiple amino acid mutations suggest that the region containing the transmembrane domains, but not the pore-forming domain, may be involved in determining differences in anesthetic sensitivity between GIRK and IRK channels. (edu.au)
  • G Protein-Coupled Inwardly-Rectifying Potassium Channel , GIRK Potassium Channel , is a family of inwardly-rectifying potassium channels activated by pertussis toxin sensitive G-protein-coupled receptors. (wellnessadvocate.com)
  • Role of G-Protein Coupled Inwardly Rectifying Potassium (GIRK) Channels in ADP-Mediated Thromboxane A2 Generation. (ashpublications.org)
  • In this study, we evaluated the role of GIRK channels in ADP- mediated TXA2 production in human platelets. (ashpublications.org)
  • We observed that GIRK channel blockers inhibit 2-MeSADP-mediated TXA2 generation. (ashpublications.org)
  • These data suggest that GIRK channel blockers inhibit TXA2 formation by interfering with agonist-induced PLA2 activation. (ashpublications.org)
  • Based on these findings we conclude that there exist different populations of GIRK channels, one that contributes to ADP- and 2-MeSADP-induced TXA2 and the other that contributes to P2Y12 receptor-dependent platelet functional responses. (ashpublications.org)
  • Also, each of the two populations of GIRK channels has varying susceptibilities to the GIRK channel blockers. (ashpublications.org)
  • Shyng S, Ferrigni T, Nichols CG (1997) Control of rectification and gating of cloned KATP channels by the Kir6.2 subunit. (springer.com)
  • For blockade of Kir4.1 channels, we tested several antidepressant agents which reportedly bound to and blocked Kir4.1 channels in a subunit-specific manner. (frontiersin.org)
  • Primary structure of a beta subunit of alpha-dendrotoxin-sensitive K+ channels from bovine brain. (pnas.org)
  • Genetic disruption of Kir6.2, the pore-forming subunit of ATP-sensitive K+ channel, predisposes to c. (biomedsearch.com)
  • To understand the cellular and in vivo functions of specific K^+ channels in glia, we have studied mice with a null mutation in the weakly inwardly rectifying K^+ channel subunit Kir4.1. (caltech.edu)
  • Homotetrameric models of three mammalian Kir channels (Kir1.1, Kir3.1, and Kir6.2) have been generated, using the KirBac3.1 transmembrane and rat Kir3.1 intracellular domain structures as templates. (ox.ac.uk)
  • Examination of the intracellular domains revealed key structural differences between Kir1.1 and Kir6.2 which may explain the difference in channel inhibition by ATP. (ox.ac.uk)
  • Only a single population of Kir channel activity, the properties of which were identical to those of K AB -2/Kir4.1 expressed in HEK293T cells, could be recorded from endfoot to the distal portion of Müller cells. (jneurosci.org)
  • Although dysfunction of astrocytic Kir4.1 channels is implicated in the development of epileptic seizures, the functional mechanisms of Kir4.1 channels in modulating epileptogenesis remain unknown. (frontiersin.org)
  • Other antidepressants (e.g., sertraline and imipramine) also increased the expression of BDNF mRNA with relative potencies similar to those for inhibition of Kir4.1 channels. (frontiersin.org)
  • The present results demonstrated that inhibition of Kir4.1 channels facilitates BDNF expression in astrocytes primarily by activating the Ras/Raf/MEK/ERK pathway, which may be linked to the development of epilepsy and other neuropsychiatric disorders. (frontiersin.org)
  • These findings suggest that dysfunction of astrocytic Kir4.1 channels can cause seizure generation probably by disrupting spatial potassium buffering. (frontiersin.org)
  • This study investigated the associations between genetic variants of KCNJ2 and KCNJ10 genes (encoding Kir2.1 and Kir4.1, respectively) and ASD risk in patients, and Kir channel expression in ASD model rats. (cdc.gov)
  • These results demonstrated that KCNJ10 (rs1186689) polymorphisms was correlated with ASD susceptibility in Chinese Han children, and the abnormal expression of Kir2.1 and Kir4.1 in ASD model rats suggested a mechanism by which Kir channels may play a role in ASD. (cdc.gov)
  • In this study, expression levels of AQP4 and Kir4.1 were for the first time examined in the brainstem and cortex, along with the functional properties of Kir channels in cultured cortical astrocytes of the SOD1G93A rat model of ALS. (ac.rs)
  • Hyperglycemia downregulates inwardly rectifying potassium channel 4.1 (Kir4.1) in cultured astrocytes. (mdpi.com)
  • Therefore, the present study aims to determine if downregulation of functional astrocytic Kir4.1 channels occurs in brains of type 2 diabetic mice and could influence hippocampal neuronal hyperexcitability. (mdpi.com)
  • Our data suggest that astrocytic dysfunction due to downregulation of Kir4.1 channels may increase seizure susceptibility by impairing astrocytic ability to maintain proper extracellular homeostasis. (mdpi.com)
  • A novel sulfonylurea receptor forms with BIR (Kir6.2) a smooth muscle type ATP-sensitive K^+ channel. (nii.ac.jp)
  • Formed through association of the Kir6.2 pore and the sulfonylurea receptor, the stress-responsive ATP-sensitive K(+) channels (K(ATP) channels), with their metabolic-sensing capability and broad tissue expression, are potential candidates for integrating the systemic adaptive response to repetitive exercise. (biomedsearch.com)
  • Here, the responses of mice lacking functional Kir6.2-containing K(ATP) channels (Kir6.2-KO) were compared with wild-type controls following a 28-day endurance swimming protocol. (biomedsearch.com)
  • Thus, Kir6.2-containing K(ATP) channel activity is required for attainment of the physiologic benefits of exercise training without injury. (biomedsearch.com)
  • Although the properties of Kir4.2 channels render them good candidates for the basis of a hepatocyte basolateral (sinusoidal) potassium conductance involved in bile formation, it has yet to be determined whether such channels are expressed in hepatocytes and, if so, where they are localized within the cell. (physiology.org)
  • The current induced by 5-HT was inwardly rectifying and associated with an increase in peak conductance and was highly selective for K+. (nih.gov)
  • Together these results indicate that serotonergic neurons of ROb and RPa are spontaneously active in a neonatal rat brain stem slice preparation and that hyperpolarization of those neurons by 5-HT1A receptor stimulation is due to pertussis toxin-sensitive G protein-mediated activation of an inwardly rectifying K+ conductance. (nih.gov)
  • 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)
  • KCNJ13 has a very low single channel conductance, low sensitivity to block by external barium and cesium, and no dependence of its inward rectification properties on the internal blocking particle magnesium. (genecards.org)
  • 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)
  • The single-channel inward current flickers with reduced conductance in an E224G mutant. (semanticscholar.org)
  • Potassium channels are present in most mammalian cells, where they participate in a wide range of physiologic responses. (antikoerper-online.de)
  • Our understanding of the mammalian inwardly rectifying family of K+ channels (Kir family) has recently been advanced by X-ray crystal structures of two homologous prokaryotic orthologs (KirBac1.1 and KirBac3.1). (ox.ac.uk)
  • Importantly, the potassium uptake current in ALS astrocytes was significantly reduced at all extracellular potassium concentrations. (ac.rs)
  • Lopatin AN, Makhina EN, Nichols CG (1994) Potassium channel block by cytoplasmic polyamines as the mechanism of intrinsic rectification. (springer.com)
  • The basic building block of a Kir channel is made up of two transmembrane helices with cytoplasmic NH 2 and COOH termini and an extracellular loop which folds back to form the pore-lining ion selectivity filter. (elsevier.com)
  • Interactions of cations with the cytoplasmic pores of inward rectifier K(+) channels in the closed state. (expasy.org)
  • Global knockout of ROMK potassium channel worsens cardiac ischemia-reperfusion injury but cardiomyocyte-specific knockout does not: Implications for the identity of mitoKATP. (nih.gov)
  • The Urinary Excretion of Uromodulin is Regulated by the Potassium Channel ROMK. (nih.gov)
  • Cloning and functional expression of a novel isoform of ROMK inwardly rectifying ATP-dependent K^+ channel,ROMK6 (Kirl.lf). (nii.ac.jp)
  • Channels made with the KCNJ1 protein, also known as ROMK, are predominantly found in the kidneys. (medlineplus.gov)
  • Genetic heterogeneity of Bartter's syndrome revealed by mutations in the K+ channel, ROMK. (medlineplus.gov)
  • Recently, we showed that the size of pre-established tumors was reduced after the depletion of Kir2.2, an inwardly rectifying potassium channel. (aacrjournals.org)
  • In a cDNA microarray hybridization analysis, we found that doxorubicin-induced senescence selectively inhibited a set of genes that included the inwardly rectifying K + channel Kir2.2. (aacrjournals.org)
  • Although previous studies have shown that K + channels may be associated with cancer, the precise functions of Kir2.2 in senescence and/or carcinogenesis remain unknown. (aacrjournals.org)
  • polyamine sensitivity of the IRK2 (Kir2.2) channel heterologously expressed in HEK293T cells. (nii.ac.jp)
  • Zusätzlich bieten wir Ihnen Potassium Inwardly-Rectifying Channel, Subfamily J, Member 1 Proteine (8) und viele weitere Produktgruppen zu diesem Protein an. (antikoerper-online.de)
  • Role of the small GTPase Rho in modulation of the inwardly rectifying potassium channel Kir2.1. (uky.edu)
  • The inwardly rectifying potassium channel Kir2.1 is inhibited by a variety of G-protein-coupled receptors (GPCRs). (uky.edu)
  • Stimulation of the m1 muscarinic receptor inhibited Kir2.1, when both receptor and channel were coexpressed in tsA201 cells. (uky.edu)
  • Defective potassium channel Kir2.1 trafficking underlies Andersen-Tawil syndrome. (medlineplus.gov)
  • Casini S, Postma AV. Decreased inward rectification of Kir2.1 channels is a novel mechanism underlying the short QT syndrome. (medlineplus.gov)
  • These results collectively show that PIP 2 sets the gain of capillary-initiated electrical signaling by modulating Kir2.1 channels. (pnas.org)
  • A ring of negative charges in the intracellular vestibule of Kir2.1 channel modulates K+ permeation. (semanticscholar.org)
  • The glutamate at site 224 of a Kir2.1 channel plays an important role in K+ permeation. (semanticscholar.org)
  • In eukaryotic cells, K + channels are involved in neural signalling and generation of the cardiac rhythm, act as effectors in signal transduction pathways involving G protein-coupled receptors (GPCRs) and may have a role in target cell lysis by cytotoxic T-lymphocytes [ PMID: 1373731 ]. (ebi.ac.uk)
  • The neuronal-type GIRK1/2 channels were inhibited by 2 minimum alveolar concentrations of halothane or F3 by 45 and 81%, respectively, whereas the cardiac-type GIRK1/4 channels were inhibited only by F3. (edu.au)
  • Channels made with the KCNJ2 protein are active in muscles used for movement (skeletal muscles) and in heart (cardiac) muscle. (medlineplus.gov)
  • In the heart, the channels are involved in recharging the cardiac muscle after each heartbeat to maintain a regular rhythm. (medlineplus.gov)
  • ATP-sensitive K+ channel knockout compromises the metabolic benefit of exercise training, resulting in cardiac deficits. (biomedsearch.com)
  • Cannabinoids were tested on Xenopus laevis oocytes coexpressing the CB 1 receptor and GIRK1 and GIRK4 channels (CB 1 /GIRK1/4) or the CB 2 receptor and GIRK1/4 channels (CB 2 /GIRK1/4). (aspetjournals.org)
  • however, the CB 2 receptor did not couple efficiently to GIRK1/4 channels. (aspetjournals.org)
  • Previous data from our laboratory has indicated that there is a functional link between the β-adrenergic receptor signaling pathway and the G-protein inwardly rectifying potassium channel (GIRK1) in human breast cancer cell lines. (biomedcentral.com)
  • Previous data from our laboratory has indicated that there is a functional link between the β-adrenergic receptor pathway and the G-protein inwardly rectifying potassium channel (GIRK1) in breast cancer cell lines and these pathways were involved in growth regulation of these cells [ 9 , 10 ]. (biomedcentral.com)
  • Several other families of ion channels also have this architecture, including calcium-activated potassium (K Ca ) channels, cyclic nucleotide-gated (CNG) and hyperpolarization-activated cyclic nucleotide-modulated (HCN) channels, and transient receptor potential (TRP) channels ( Fig. 1 and see below). (aspetjournals.org)
  • KATP Channels are 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. (wellnessadvocate.com)
  • Among others, genes for dopamine receptor D2 DRD2 and the inwardly rectifying potassium channel Kir2.3 were found to be over-expressed in microarray analysis. (duhnnae.com)
  • We recently demonstrated that G-protein gated inwardly rectifying potassium channels (GIRKs) are important for P2Y12 receptor-mediated platelet functional responses, namely platelet aggregation, dense granule secretion and Akt phosphorylation. (ashpublications.org)
  • The KirBac family exhibited a range of sensitivity to the K+ channel blockers Ba2+ and Cs+ as well as differences in their ability to grow on very low-K+ media, thus demonstrating major differences in their permeation properties. (ox.ac.uk)
  • Differential polyamine sensitivity in inwardly rectifying Kir2 potassium channels. (semanticscholar.org)
  • See the reference protein sequence for ATP-sensitive inward rectifier potassium channel 1 isoform 1 (NP_001161826.1). (nih.gov)
  • The short-form isoform shared 86-91% identity with the mouse, human, and guinea pig channels. (physiology.org)
  • Here we have cloned the rat homologue of Kir4.2 and a new isoform of an inwardly rectifying potassium channel (Kir4.2a) from rat hepatocytes. (physiology.org)
  • There are seven Kir channel subfamilies that can be classified into four functional groups: classical Kir channels (Kir2.x) are constitutively active, G protein-gated Kir channels (Kir3.x) are regulated by G protein-coupled receptors, ATP-sensitive K + channels (Kir6.x) are tightly linked to cellular metabolism, and K + transport channels (Kir1.x, Kir4.x, Kir5.x, and Kir7.x). (elsevier.com)
  • In summary, it appears the CB 1 and CB 2 receptors couple differently to GIRK1/4 channels. (aspetjournals.org)
  • We feel that this data may indicate that stimulation of GIRK1 or GIRK2 channels may be important in lung cancer. (biomedcentral.com)
  • Expression of mRNA that encodes a G-protein coupled inwardly rectifying potassium channel (GIRK1) has been shown in tissue samples from approximately 40% of primary human breast cancers tested [ 6 ], and this expression of GIRK1 was associated with a more aggressive clinical behavior. (biomedcentral.com)
  • Methods: The voltage-gated (ERG1, ELK1, and KCNQ2/3) and inwardly rectifying (GIRK1/2, GIRK1/4, GIRK2, IRK1, and ROMK1) potassium channels were expressed in Xenopus oocytes. (edu.au)
  • Lu Z (2004) Mechanism of rectification in inward-rectifier K+ channels. (springer.com)
  • Our second study sought to uncover the mechanism that K IR channels utilize to sense changes in pressure. (uwo.ca)
  • We therefore tested whether endocannabinoids inhibit N-type voltage-dependent Ca 2+ channels by activating G i/o -protein-coupled CB1 cannabinoid receptors (CB1R)-a possible mechanism underlying DSI/DSE. (aspetjournals.org)
  • This direct-coupling mechanism contrasts with allosteric mechanisms proposed for hyperpolarization-activated cyclic nucleotide-gated channels 5 , and may represent an unexpected link between depolarization- and hyperpolarization-activated channels. (nature.com)
  • Männikkö, R., Elinder, F. & Larsson, H. P. Voltage-sensing mechanism is conserved among ion channels gated by opposite voltages. (nature.com)
  • Blunck, R. & Batulan, Z. Mechanism of electromechanical coupling in voltage-gated potassium channels. (nature.com)
  • The inward-rectifier potassium channel family (also known as 2-TM channels) include the strong inward-rectifier channels (Kir2.x), the G-protein-activated inward-rectifier channels (Kir3.x) and the ATP-sensitive channels (Kir6.x), which combine with sulphonylurea receptors. (genecards.org)
  • In addition, spatial potassium buffering is known to be linked to glutamate and water uptake by astrocytes ( Olsen and Sontheimer, 2008 ). (frontiersin.org)
  • Potassium flux through hepatocellular basolateral membrane channels may provide the counterion for apical anion efflux. (physiology.org)
  • Electrophysiological properties of Kir channels make them well-suited candidates for coupling basolateral K + efflux with luminal secretion in cells, like hepatocytes, that do not undergo the oscillations in membrane potential that are requisite for opening of voltage-gated K + channels (Kv), and/or do not couple increases in cytosolic Ca 2+ to secretion ( 20 ). (physiology.org)
  • Enkvetchakul D, Jeliazkova I, Nichols CG (2005) Direct modulation of Kir channel gating by membrane phosphatidylinositol 4,5-bisphosphate. (springer.com)
  • Kir7.1 is an inwardly rectifying potassium channel that has been implicated in controlling the resting membrane potential of the myometrium. (warwick.ac.uk)
  • 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)
  • Voltage-gated potassium (K v ) channels coordinate electrical signalling and control cell volume by gating in response to membrane depolarization or hyperpolarization. (nature.com)
  • 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)
  • Inward rectifiers play a role in setting cellular membrane potentials, and closing of these channels upon depolarization permits the occurrence of long duration action potentials with a plateau phase. (wikipedia.org)
  • 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)
  • In pancreatic β-cells, ATP-sensitive potassium (K ATP ) channels control insulin secretion by coupling metabolism to membrane electrical activity. (diabetesjournals.org)
  • Ion channels establish and regulate membrane potentials in excitable and non-excitable cells. (biologists.org)
  • Knowledge of how membrane conduction properties changed during the evolution of multicellularity would be aided by the comparative analysis of K + channels from phyla occupying basal positions. (biologists.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)
  • These results reveal the existence of a functionally diverse superfamily of microbial KirBac genes and present an excellent resource for the structural and functional analysis of this class of K+ channels. (ox.ac.uk)
  • Twelve tag single nucleotide polymorphisms (SNPs) from the KCNJ2 and KCNJ10 genes were genotyped by Sequenom Mass Array, while a valproic acid (VPA)-induced rat model of ASD was used to evaluate Kir channel expression in the hippocampus. (cdc.gov)
  • This Norwegian study aimed to test the hypothesis that specific variants of genes involved in water transport and potassium homeostasis would be predisposing factors for SIDS. (cdc.gov)
  • The G protein-coupled inwardly-rectifying potassium channels (GIRKs) are a family of lipid-gated inward-rectifier potassium ion channels which are activated (opened) by the signaling lipid PIP2 and a signal transduction cascade starting with ligand-stimulated G protein-coupled receptors (GPCRs). (wikipedia.org)
  • G-Protein-coupled inwardly rectifying potassium channels (GIRKs) regulate synaptic transmission and neuronal firing rates. (aspetjournals.org)
  • The K ir 3.1/3.4 channel is activated by G-protein coupled receptors linked to G αi /G βγ heterotrimers. (guidetopharmacology.org)
  • Calcium can act in signal transduction after influx resulting from activation of ion channels or as a second messenger caused by indirect signal transduction pathways such as G protein-coupled receptors. (wikipathways.org)
  • We employed a yeast genetic screen to identify functional channels from libraries of K(ir) 2.1 containing mutagenized M1 or M2 domains. (nih.gov)
  • Additionally, functional expression in HEK293T cells reveals properties supporting the proposal that this channel may provide the major K + -selective current component in the rat hepatocyte. (physiology.org)
  • 1 2 3 4 5 6 This Brief Review will first provide a short description of the functional characteristics of the 4 main types of vascular K + channels and the likely physiological importance of these channels, as well as the phenomenon of K + channel-mediated, endothelium-dependent vascular hyperpolarization. (ahajournals.org)
  • A functional model for G protein activation of the muscarinie K^+ channel in guinea pig atrial myocytes : spectral analysis of the effect of GTP on single-channel Kinetics. (nii.ac.jp)
  • Cloning and functional characterization of a superfamily of microbial inwardly rectifying potassium channels. (ox.ac.uk)
  • However, the functional properties of these KirBac channels are still poorly understood. (ox.ac.uk)
  • Furthermore, the complementation assay used in this study provides a simple and robust method for the functional characterization of a range of prokaryotic K+ channels that are difficult to study by traditional methods. (ox.ac.uk)
  • Both channels are important for the maintainance of a functional BBB astrocytic lining. (ac.rs)
  • How functional diversification of ion channels contributed to the evolution of nervous systems may be understood by studying organisms at key positions in the evolution of animal multicellularity. (biologists.org)
  • In this study, we report the cloning and functional characterization of the first ion channels isolated from a sponge ( Amphimedon queenslandica , Demospongiae, Porifera). (biologists.org)
  • Primary structure and functional expression of a mouse inward rectifier potassium channel [see comments]. (nii.ac.jp)
  • Conversely, IRK1 and ROMK1 channels were completely resistant to all anesthetics tested. (edu.au)
  • The pore properties of AmqKir channels demonstrated strong K + selectivity and block by Cs + and Ba 2+ . (biologists.org)
  • Many KCNJ2 mutations prevent PIP2 from effectively binding to and activating potassium channels. (medlineplus.gov)
  • These mutations change single amino acids in the KCNJ2 protein, which increases the activity of channels made with this protein. (medlineplus.gov)
  • However, in the Arabidopsis thaliana stomatal K in channel KAT1, mutations in the unique histidine exposed to the solvent (His 267 ) do not affect the pH dependency. (portlandpress.com)
  • Inwardly rectifying potassium (Kir) 4.1 channels in astrocytes regulate neuronal excitability by mediating spatial potassium buffering. (frontiersin.org)
  • The changes in the studied channels, notably at the upper CNS level, could underline the hampered ability of astrocytes to maintain water and potassium homeostasis, thus affecting the BBB, disturbing the neuronal microenvironment, and causing motoneuronal dysfunction and death. (ac.rs)
  • Astrocytes are connected through connexin-based gap junction channels, with brain region specificities, and those networks modulate neuronal activities, such as those involved in sleep-wake cycle, cognitive, or sensory functions. (frontiersin.org)
  • We further show that chemical factors released in the brain, including those associated with neuronal activity, cause changes in the levels of PIP 2 , thereby altering endothelial potassium channel signaling and controlling cerebral blood flow. (pnas.org)
  • Examples of GIRKs include a subset of potassium channels in the heart, which, when activated by parasympathetic signals such as acetylcholine through M2 muscarinic receptors, causes an outward current of potassium, which slows down the heart rate. (wikipedia.org)
  • Inward-rectifier potassium channels ( K ir , IRK ) are a specific subset of potassium channels . (wikipedia.org)
  • The IRK2 channels showed strong inward rectification in the cell-attached configuration of the patch-clamp method. (nii.ac.jp)
  • polyamine to the channel and (2) raise a possibility that artificial polyvalent cations introduced into cardiocytes might be utilized to pharmacologically modulate the strong inward rectification of the channels induced by intracellular polyamines. (nii.ac.jp)
  • In addition, in neurons recorded with pipettes containing GTP gamma S (0.1 mM), 5-HT induced an inwardly rectifying current that did not reverse on washing. (nih.gov)
  • ATP-sensitive potassium (K(ATP)) channels are found in endocrine cells, neurons and both smooth and striated muscle, where they play an important role in controlling insulin secretion and vascular tone, and protect neurons under metabolic stress. (thermofisher.com)
  • and spermine foe a cloned IRK2 channel expressed in human cell' J.Physiol. (nii.ac.jp)
  • Particularly, the observed changes in the expression of both channels were retained in cultured astrocytes. (ac.rs)
  • In animal models, in response to subarachnoid blood, a dynamic transition of ion channel expression and function is initiated, with acute and long-term effects differing from each other. (hindawi.com)
  • Initial hypoperfusion after exposure of cerebral vessels to oxyhemoglobin correlates with a suppression of voltage-gated potassium channel activity, whereas delayed cerebral vasospasm involves changes in other potassium channel and voltage-gated calcium channels expression and function. (hindawi.com)
  • Furthermore, expression patterns and function of ion channels appear to differ between main and small peripheral vessels, which may be key in understanding mechanisms behind subarachnoid hemorrhage-induced vasospasm. (hindawi.com)
  • 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)
  • Because vasospastic smooth muscle cells are known to be depolarized compared to controls [ 3 , 4 ], the expression and function of ion channels in these cells after SAH are of great interest. (hindawi.com)
  • The goal of the present analysis is to review ion channel expression and function in healthy cerebral blood vessels as well as after SAH. (hindawi.com)
  • [16] The relative contribution of each of these two inhibitory mechanisms depends on the variance of ion channel expression by cell type. (wikipedia.org)
  • For example, activation of acetylcholine M2 or M4 receptors, purinergic or somatostatin receptors result in direct G βγ activation of the channel. (guidetopharmacology.org)
  • Current responses of GIRK2 channels activated by μ-opioid receptors were also inhibited by halothane. (edu.au)
  • Through these experiments, we determined which specific subtypes of K IR channels were functionally relevant in smooth muscle cells. (uwo.ca)
  • Among the functionally diverse K + channels, inwardly rectifying (Kir) channels are unusual in that they preferentially conduct K + from the extracellular compartment into the cell. (biologists.org)
  • Using RT-PCR analysis, we found that inward rectifier K channel 6.1 (Kir6.1) and sulfonylurea 2B (SUR2B) transcripts were predominantly expressed in rabbit femoral artery. (nii.ac.jp)
  • was further applied to the channel in the presence of spermine, the inward rectification of the channel was paradoxically attenuated compared with that in the presence of spermine alone. (nii.ac.jp)
  • and spermine compete with each other through binding the same binding site (s) on the channel. (nii.ac.jp)
  • Positively to inwardly rectifying and A-type outward potassium channels. (wikipedia.org)
  • [4] IRK channels possess a pore domain, homologous to that of voltage-gated ion channels , and flanking transmembrane segments (TMSs). (wikipedia.org)
  • May be responsible for potassium buffering action of glial cells in the brain. (uniprot.org)
  • Vardanyan, V. & Pongs, O. Coupling of voltage-sensors to the channel pore: a comparative view. (nature.com)
  • The architectures of the ion channel families consist of four variations built upon a common pore-forming structural theme. (aspetjournals.org)
  • and two-pore potassium channels. (sciencemag.org)
  • Polyamine blockade of inwardly rectifying potassium (Kir) channels underlies their steep voltage--dependence observed in native cells. (springer.com)
  • The structural determinants of polyamine blockade and the structure-activity profile of endogenous polyamines requires specialized methodology for characterizing polyamine interactions with Kir channels. (springer.com)
  • Several methods for measuring polyamine interactions with prokaryotic and eukaryotic Kir channels are discussed. (springer.com)
  • Kurata H.T., Cheng W.W.L., Nichols C.G. (2011) Polyamine Block of Inwardly Rectifying Potassium Channels. (springer.com)
  • Analysis of the polyamine-binding sites in inwardly rectifying K^+ channels. (nii.ac.jp)
  • Polyamine block is likely to underlie the inward rectification of IRK2 channels in intact cells. (nii.ac.jp)