Potassium Channel Blockers: 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 Channels: 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.Potassium: 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.4-Aminopyridine: 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.Tetraethylammonium: A potassium-selective ion channel blocker. (From J Gen Phys 1994;104(1):173-90)Calcium Channel Blockers: A class of drugs that act by selective inhibition of calcium influx through cellular membranes.Potassium Channels, Inwardly Rectifying: Potassium channels where the flow of K+ ions into the cell is greater than the outward flow.Potassium Channels, Voltage-Gated: 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.Ion Channels: 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.Glyburide: An antidiabetic sulfonylurea derivative with actions similar to those of chlorpropamide.Tetraethylammonium CompoundsMembrane Potentials: 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).Shaker Superfamily of Potassium Channels: 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.Aminopyridines: Pyridines substituted in any position with an amino group. May be hydrogenated, but must retain at least one double bond.Kv1.3 Potassium Channel: A delayed rectifier subtype of shaker potassium channels that is the predominant VOLTAGE-GATED POTASSIUM CHANNEL of T-LYMPHOCYTES.Charybdotoxin: A 37-amino acid residue peptide isolated from the scorpion Leiurus quinquestriatus hebraeus. It is a neurotoxin that inhibits calcium activated potassium channels.Calcium Channels: 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.Apamin: 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.Ion Channel Gating: 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.Patch-Clamp Techniques: 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.Potassium Channels, Calcium-Activated: Potassium channels whose activation is dependent on intracellular calcium concentrations.Scorpion Venoms: 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.Kv1.2 Potassium Channel: A delayed rectifier subtype of shaker potassium channels that is selectively inhibited by a variety of SCORPION VENOMS.Kv1.1 Potassium Channel: A delayed rectifier subtype of shaker potassium channels that is commonly mutated in human episodic ATAXIA and MYOKYMIA.Electrophysiology: 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.Ether-A-Go-Go Potassium Channels: 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.Cromakalim: 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)Shaw Potassium Channels: A shaker subfamily that is prominently expressed in NEURONS and are necessary for high-frequency, repetitive firing of ACTION POTENTIALS.Action Potentials: Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.Calcium: 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.KCNQ1 Potassium Channel: A voltage-gated potassium channel that is expressed primarily in the HEART.KCNQ Potassium Channels: 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.Sodium Channel Blockers: 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.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Kv1.5 Potassium Channel: 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.Large-Conductance Calcium-Activated Potassium Channels: 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.Guinea Pigs: 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.KATP Channels: 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.Shab Potassium Channels: 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.Kv1.4 Potassium Channel: A fast inactivating subtype of shaker potassium channels that contains two inactivation domains at its N terminus.Rats, Sprague-Dawley: 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.Chloride Channels: Cell membrane glycoproteins that form channels to selectively pass chloride ions. Nonselective blockers include FENAMATES; ETHACRYNIC ACID; and TAMOXIFEN.Potassium Channels, Tandem Pore Domain: 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.Phenethylamines: A group of compounds that are derivatives of beta- aminoethylbenzene which is structurally and pharmacologically related to amphetamine. (From Merck Index, 11th ed)KCNQ2 Potassium Channel: A very slow opening and closing voltage-gated potassium channel that is expressed in NEURONS and is commonly mutated in BENIGN FAMILIAL NEONATAL CONVULSIONS.KCNQ3 Potassium Channel: 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.Shal Potassium Channels: 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.Anti-Arrhythmia Agents: 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.Small-Conductance Calcium-Activated Potassium Channels: 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.Neurons: 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.G Protein-Coupled Inwardly-Rectifying Potassium Channels: 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.Delayed Rectifier Potassium Channels: 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.Vasodilator Agents: Drugs used to cause dilation of the blood vessels.Calcium Channels, L-Type: 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.Electric Conductivity: The ability of a substrate to allow the passage of ELECTRONS.Rats, Wistar: A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.Electric Stimulation: Use of electric potential or currents to elicit biological responses.Cells, Cultured: 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.Oocytes: 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).Nifedipine: A potent vasodilator agent with calcium antagonistic action. It is a useful anti-anginal agent that also lowers blood pressure.Vasodilation: The physiological widening of BLOOD VESSELS by relaxing the underlying VASCULAR SMOOTH MUSCLE.Xenopus laevis: 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.Intermediate-Conductance Calcium-Activated Potassium Channels: 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.Piperidines: A family of hexahydropyridines.Pinacidil: 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)Dihydropyridines: Pyridine moieties which are partially saturated by the addition of two hydrogen atoms in any position.Xenopus: An aquatic genus of the family, Pipidae, occurring in Africa and distinguished by having black horny claws on three inner hind toes.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Barium: 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.Calcium Channels, N-Type: CALCIUM CHANNELS that are concentrated in neural tissue. Omega toxins inhibit the actions of these channels by altering their voltage dependence.Large-Conductance Calcium-Activated Potassium Channel alpha Subunits: The pore-forming subunits of large-conductance calcium-activated potassium channels. They form tetramers in CELL MEMBRANES.Sodium: A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.Verapamil: A calcium channel blocker that is a class IV anti-arrhythmia agent.Diltiazem: A benzothiazepine derivative with vasodilating action due to its antagonism of the actions of CALCIUM ion on membrane functions.Enzyme Inhibitors: Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction.Calcium Channels, T-Type: 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.Adenosine Triphosphate: 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.Barium Compounds: Inorganic compounds that contain barium as an integral part of the molecule.Sulfonylurea Receptors: 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.Kinetics: The rate dynamics in chemical or physical systems.Calcium Channel Agonists: 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.Potassium, Dietary: Potassium or potassium compounds used in foods or as foods.Endothelium, Vascular: Single pavement layer of cells which line the luminal surface of the entire vascular system and regulate the transport of macromolecules and blood components.Molecular Sequence Data: 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.Amino Acid Sequence: 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.Benzopyrans: Compounds with a core of fused benzo-pyran rings.Decanoic Acids: 10-carbon saturated monocarboxylic acids.Potassium Chloride: 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.TRPC Cation Channels: 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.Diazoxide: A benzothiadiazine derivative that is a peripheral vasodilator used for hypertensive emergencies. It lacks diuretic effect, apparently because it lacks a sulfonamide group.Hydroxy Acids: Organic compounds containing both the hydroxyl and carboxyl radicals.Ion Transport: 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.Chlorides: Inorganic compounds derived from hydrochloric acid that contain the Cl- ion.Cyclic Nucleotide-Gated Cation Channels: 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.Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Nicorandil: 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.Potassium Deficiency: 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)Cesium: 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.Nitrobenzoates: Benzoic acid or benzoic acid esters substituted with one or more nitro groups.Receptors, Drug: 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.Tetrodotoxin: 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.Elapid Venoms: 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.Potassium Compounds: Inorganic compounds that contain potassium as an integral part of the molecule.Large-Conductance Calcium-Activated Potassium Channel beta Subunits: The regulatory subunits of large-conductance calcium-activated potassium channels.Cell Line: Established cell cultures that have the potential to propagate indefinitely.Mibefradil: A benzimidazoyl-substituted tetraline that selectively binds and inhibits CALCIUM CHANNELS, T-TYPE.TRPV Cation Channels: 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.Epithelial Sodium Channels: 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.Protein Subunits: 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.Nicardipine: A potent calcium channel blockader with marked vasodilator action. It has antihypertensive properties and is effective in the treatment of angina and coronary spasms without showing cardiodepressant effects. It has also been used in the treatment of asthma and enhances the action of specific antineoplastic agents.Mutation: 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.TRPM Cation Channels: 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.Acid Sensing Ion Channels: 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.PhenylenediaminesScorpions: 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)Myocardium: 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.Protein Structure, Tertiary: 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.omega-Conotoxin GVIA: A neurotoxic peptide, which is a cleavage product (VIa) of the omega-Conotoxin precursor protein contained in venom from the marine snail, CONUS geographus. It is an antagonist of CALCIUM CHANNELS, N-TYPE.Angiotensin II Type 1 Receptor Blockers: Agents that antagonize ANGIOTENSIN II TYPE 1 RECEPTOR. Included are ANGIOTENSIN II analogs such as SARALASIN and biphenylimidazoles such as LOSARTAN. Some are used as ANTIHYPERTENSIVE AGENTS.omega-Conotoxins: A family of structurally related neurotoxic peptides from mollusk venom that inhibit voltage-activated entry of calcium into the presynaptic membrane. They selectively inhibit N-, P-, and Q-type calcium channels.Amlodipine: A long-acting dihydropyridine calcium channel blocker. It is effective in the treatment of ANGINA PECTORIS and HYPERTENSION.Rubidium: 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.Models, Molecular: Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.Potassium Isotopes: 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.Nimodipine: A calcium channel blockader with preferential cerebrovascular activity. It has marked cerebrovascular dilating effects and lowers blood pressure.Niflumic Acid: An analgesic and anti-inflammatory agent used in the treatment of rheumatoid arthritis.Rabbits: 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.Quinidine: 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.Nitrendipine: A calcium channel blocker with marked vasodilator action. It is an effective antihypertensive agent and differs from other calcium channel blockers in that it does not reduce glomerular filtration rate and is mildly natriuretic, rather than sodium retentive.Models, Biological: 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.Muscle, Smooth, Vascular: The nonstriated involuntary muscle tissue of blood vessels.Calcium Channels, P-Type: CALCIUM CHANNELS located within the PURKINJE CELLS of the cerebellum. They are involved in stimulation-secretion coupling of neurons.Heart: The hollow, muscular organ that maintains the circulation of the blood.Kv1.6 Potassium Channel: A delayed rectifier subtype of shaker potassium channels that has been described in NEURONS and ASTROCYTES.Hydrogen-Ion Concentration: 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)CHO Cells: 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.Potassium Radioisotopes: 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.Cricetinae: A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.Peptides: 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.Long QT Syndrome: 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.Transfection: 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.Cations: Positively charged atoms, radicals or groups of atoms which travel to the cathode or negative pole during electrolysis.Benzimidazoles: Compounds with a BENZENE fused to IMIDAZOLES.Minoxidil: 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)Quaternary Ammonium Compounds: 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.HEK293 Cells: A cell line generated from human embryonic kidney cells that were transformed with human adenovirus type 5.Antihypertensive Agents: Drugs used in the treatment of acute or chronic vascular HYPERTENSION regardless of pharmacological mechanism. Among the antihypertensive agents are DIURETICS; (especially DIURETICS, THIAZIDE); ADRENERGIC BETA-ANTAGONISTS; ADRENERGIC ALPHA-ANTAGONISTS; ANGIOTENSIN-CONVERTING ENZYME INHIBITORS; CALCIUM CHANNEL BLOCKERS; GANGLIONIC BLOCKERS; and VASODILATOR AGENTS.Tolbutamide: A sulphonylurea hypoglycemic agent with actions and uses similar to those of CHLORPROPAMIDE. (From Martindale, The Extra Pharmacopoeia, 30th ed, p290)Dogs: 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)Kv Channel-Interacting Proteins: A family of neuronal calcium-sensor proteins that interact with and regulate potassium channels, type A.Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels: 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.Ions: 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.Calcium Channels, Q-Type: CALCIUM CHANNELS located in the neurons of the brain.Transient Receptor Potential Channels: 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.Cell Membrane Permeability: A quality of cell membranes which permits the passage of solvents and solutes into and out of cells.Amiloride: A pyrazine compound inhibiting SODIUM reabsorption through SODIUM CHANNELS in renal EPITHELIAL CELLS. This inhibition creates a negative potential in the luminal membranes of principal cells, located in the distal convoluted tubule and collecting duct. Negative potential reduces secretion of potassium and hydrogen ions. Amiloride is used in conjunction with DIURETICS to spare POTASSIUM loss. (From Gilman et al., Goodman and Gilman's The Pharmacological Basis of Therapeutics, 9th ed, p705)4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid: An inhibitor of anion conductance including band 3-mediated anion transport.Cation Transport Proteins: Membrane proteins whose primary function is to facilitate the transport of positively charged molecules (cations) across a biological membrane.Streptomyces lividans: An actinomycete used for production of commercial ANTIBIOTICS and as a host for gene cloning.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Protein Conformation: 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).Acetylcholine: 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.Mutagenesis, Site-Directed: Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.Spider Venoms: Venoms of arthropods of the order Araneida of the ARACHNIDA. The venoms usually contain several protein fractions, including ENZYMES, hemolytic, neurolytic, and other TOXINS, BIOLOGICAL.Cnidarian Venoms: 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.ATP-Binding Cassette Transporters: 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.Sodium Channels: Ion channels that specifically allow the passage of SODIUM ions. A variety of specific sodium channel subtypes are involved in serving specialized functions such as neuronal signaling, CARDIAC MUSCLE contraction, and KIDNEY function.NAV1.5 Voltage-Gated Sodium Channel: 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.RNA, Messenger: 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.Muscle Contraction: A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.omega-Agatoxin IVA: A neuropeptide toxin from the venom of the funnel web spider, Agelenopsis aperta. It inhibits CALCIUM CHANNELS, P-TYPE by altering the voltage-dependent gating so that very large depolarizations are needed for channel opening. It also inhibits CALCIUM CHANNELS, Q-TYPE.Muscle, Smooth: 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)Magnesium: 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.Biophysics: The study of PHYSICAL PHENOMENA and PHYSICAL PROCESSES as applied to living things.Decapodiformes: 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.Picolines: A group of compounds that are monomethyl derivatives of pyridines. (From Dorland, 28th ed)Hippocampus: 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.Neurotoxins: 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.Diuretics: Agents that promote the excretion of urine through their effects on kidney function.Kidney: Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.Recombinant Proteins: Proteins prepared by recombinant DNA technology.RNA, Complementary: 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)Lidocaine: A local anesthetic and cardiac depressant used as an antiarrhythmia agent. Its actions are more intense and its effects more prolonged than those of PROCAINE but its duration of action is shorter than that of BUPIVACAINE or PRILOCAINE.Structure-Activity Relationship: 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.Hypokalemia: 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)Ryanodine Receptor Calcium Release Channel: 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.Isradipine: A potent antagonist of CALCIUM CHANNELS that is highly selective for VASCULAR SMOOTH MUSCLE. It is effective in the treatment of chronic stable angina pectoris, hypertension, and congestive cardiac failure.Calcium Channels, R-Type: CALCIUM CHANNELS located in the neurons of the brain. They are inhibited by the marine snail toxin, omega conotoxin MVIIC.Rubidium Radioisotopes: Unstable isotopes of rubidium that decay or disintegrate emitting radiation. Rb atoms with atomic weights 79-84, and 86-95 are radioactive rubidium isotopes.Guanidines: 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.Sequence Homology, Amino Acid: The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.Potassium Iodide: 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)Myocytes, Cardiac: Striated muscle cells found in the heart. They are derived from cardiac myoblasts (MYOBLASTS, CARDIAC).Extracellular Space: 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.Hypertension: Persistently high systemic arterial BLOOD PRESSURE. Based on multiple readings (BLOOD PRESSURE DETERMINATION), hypertension is currently defined as when SYSTOLIC PRESSURE is consistently greater than 140 mm Hg or when DIASTOLIC PRESSURE is consistently 90 mm Hg or more.Voltage-Gated Sodium Channel Blockers: A class of drugs that inhibit the activation of VOLTAGE-GATED SODIUM CHANNELS.Muscle Relaxation: That phase of a muscle twitch during which a muscle returns to a resting position.Cricetulus: 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.Sarcolemma: The excitable plasma membrane of a muscle cell. (Glick, Glossary of Biochemistry and Molecular Biology, 1990)Blood Pressure: PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.Azetidinecarboxylic Acid: A proline analog that acts as a stoichiometric replacement of proline. It causes the production of abnormal proteins with impaired biological activity.

Ionic currents underlying spontaneous action potentials in isolated cerebellar Purkinje neurons. (1/3001)

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

RINm5f cells express inactivating BK channels whereas HIT cells express noninactivating BK channels. (2/3001)

Large-conductance Ca2+- and voltage-activated BK-type K+ channels are expressed abundantly in normal rat pancreatic islet cells and in the clonal rat insulinoma tumor (RINm5f) and hamster insulinoma tumor (HIT) beta cell lines. Previous work has suggested that the Ca2+ sensitivity of BK channels in RIN cells is substantially less than that in HIT cells, perhaps contributing to differences between the cell lines in responsiveness to glucose in mediating insulin secretion. In both RIN cells and normal pancreatic beta cells, BK channels are thought to play a limited role in responses of beta cells to secretagogues and in the electrical activity of beta cells. Here we examine in detail the properties of BK channels in RIN and HIT cells using inside-out patches and whole cell recordings. BK channels in RIN cells exhibit rapid inactivation that results in an anomalous steady-state Ca2+ dependence of activation. In contrast, BK channels in HIT cells exhibit the more usual noninactivating behavior. When BK inactivation is taken into account, the Ca2+ and voltage dependence of activation of BK channels in RIN and HIT cells is essentially indistinguishable. The properties of BK channel inactivation in RIN cells are similar to those of inactivating BK channels (termed BKi channels) previously identified in rat chromaffin cells. Inactivation involves multiple, trypsin-sensitive cytosolic domains and exhibits a dependence on Ca2+ and voltage that appears to arise from coupling to channel activation. In addition, the rates of inactivation onset and recovery are similar to that of BKi channels in chromaffin cells. The charybdotoxin (CTX) sensitivity of BKi currents is somewhat less than that of the noninactivating BK variant. Action potential voltage-clamp waveforms indicate that BK current is activated only weakly by Ca2+ influx in RIN cells but more strongly activated in HIT cells even when Ca2+ current magnitude is comparable. Concentrations of CTX sufficient to block BKi current in RIN cells have no effect on action potential activity initiated by glucose or DC injection. Despite its abundant expression in RIN cells, BKi current appears to play little role in action potential activity initiated by glucose or DC injection in RIN cells, but BK current may play an important role in action potential repolarization in HIT cells.  (+info)

Characterization of K+ currents underlying pacemaker potentials of fish gonadotropin-releasing hormone cells. (3/3001)

Endogenous pacemaker activities are important for the putative neuromodulator functions of the gonadotropin-releasing hormone (GnRH)-immunoreactive terminal nerve (TN) cells. We analyzed several types of voltage-dependent K+ currents to investigate the ionic mechanisms underlying the repolarizing phase of pacemaker potentials of TN-GnRH cells by using the whole brain in vitro preparation of fish (dwarf gourami, Colisa lalia). TN-GnRH cells have at least four types of voltage-dependent K+ currents: 1) 4-aminopyridine (4AP)-sensitive K+ current, 2) tetraethylammonium (TEA)-sensitive K+ current, and 3) and 4) two types of TEA- and 4AP-resistant K+ currents. A transient, low-threshold K+ current, which was 4AP sensitive and showed significant steady-state inactivation in the physiological membrane potential range (-40 to -60 mV), was evoked from a holding potential of -100 mV. This current thus cannot contribute to the repolarizing phase of pacemaker potentials. TEA-sensitive K+ current evoked from a holding potential of -100 mV was slowly activating, long lasting, and showed comparatively low threshold of activation. This current was only partially inactivated at steady state of -60 to -40 mV, which is equivalent to the resting membrane potential. TEA- and 4AP-resistant sustained K+ currents were evoked from a holding potential of -100 mV and were suggested to consist of two types, based on the analysis of activation curves. From the inactivation and activation curves, it was suggested that one of them with low threshold of activation may be partly involved in the repolarizing phase of pacemaker potentials. Bath application of TEA together with tetrodotoxin reversibly blocked the pacemaker potentials in current-clamp recordings. We conclude that the TEA-sensitive K+ current is the most likely candidate that contributes to the repolarizing phase of the pacemaker potentials of TN-GnRH cells.  (+info)

Calcium responses induced by acetylcholine in submucosal arterioles of the guinea-pig small intestine. (4/3001)

1. Calcium responses induced by brief stimulation with acetylcholine (ACh) were assessed from the fluorescence changes in fura-2 loaded submucosal arterioles of the guinea-pig small intestine. 2. Initially, 1-1.5 h after loading with fura-2 (fresh tissues), ACh increased [Ca2+]i in a concentration-dependent manner. This response diminished with time, and finally disappeared in 2-3 h (old tissues). 3. Ba2+ elevated [Ca2+]i to a similar extent in both fresh and old tissues. ACh further increased the Ba2+-elevated [Ca2+]i in fresh tissues, but reduced it in old tissues. Responses were not affected by either indomethacin or nitroarginine. 4. In fresh mesenteric arteries, mechanical removal of endothelial cells abolished the ACh-induced increase in [Ca2+]i, with no alteration of [Ca2+]i at rest and during elevation with Ba2+. 5. In the presence of indomethacin and nitroarginine, high-K+ solution elevated [Ca2+]i in both fresh and old tissues. Subsequent addition of ACh further increased [Ca2+]i in fresh tissues without changing it in old tissues. 6. Proadifen, an inhibitor of the enzyme cytochrome P450 mono-oxygenase, inhibited the ACh-induced changes in [Ca2+]i in both fresh and Ba2+-stimulated old tissues. It also inhibited the ACh-induced hyperpolarization. 7. In fresh tissues, the ACh-induced Ca2+ response was not changed by apamin, charybdotoxin (CTX), 4-aminopyridine (4-AP) or glibenclamide. In old tissues in which [Ca2+]i had previously been elevated with Ba2+, the ACh-induced Ca2+ response was inhibited by CTX but not by apamin, 4-AP or glibenclamide. 8. It is concluded that in submucosal arterioles, ACh elevates endothelial [Ca2+]i and reduces muscular [Ca2+]i, probably through the hyperpolarization of endothelial or smooth muscle membrane by activating CTX-sensitive K+ channels.  (+info)

Volume regulation following hypotonic shock in isolated crypts of mouse distal colon. (5/3001)

1. A video-imaging technique of morphometry was used to measure the diameter as an index of cell volume in intact mouse distal colon crypts submitted to hypotonic shock. 2. Transition from isotonic (310 mosmol l-1) to hypotonic (240 mosmol l-1) saline caused a pronounced increase in crypt diameter immediately followed by regulatory volume decrease (RVD). 3. Exposure of crypts to Cl--free hyposmotic medium increased the rapidity of both cell swelling and RVD. Exposure of crypts to Na+-free hyposmotic medium reduced the total duration of swelling. Return to initial diameter was followed by further shrinkage of the crypt cells. 4. The chloride channel inhibitor NPPB (50 microM) delayed the swelling phase and prevented the subsequent normal decrease in diameter. 5. The K+ channel blockers barium (10 mM), charybdotoxin (10 nM) and TEA (5 mM) inhibited RVD by 51, 44 and 32 %, respectively. 6. Intracellular [Ca2+] rose from a baseline of 174 +/- 17 nM (n = 8) to 448 +/- 45 nM (n = 8) during the initial swelling phase 7. The Ca2+ channel blockers verapamil (50 microM) and nifedipine (10 microM), the chelator of intracellular Ca2+ BAPTA AM (30 microM), or the inhibitor of Ca2+ release TMB-8 (10 microM), dramatically reduced volume recovery, leading to 51 % (n = 9), 25 % (n = 7), 37 % (n = 6), 32 % (n = 8) inhibition of RVD, respectively. TFP (50 microM), an antagonist of the Ca2+-calmodulin complex, significantly slowed RVD. The Ca2+ ionophore A23187 (2 microM) provoked a dramatic reduction of the duration and amplitude of cell swelling followed by extensive shrinkage. The release of Ca2+ from intracellular stores using bradykinin (1 microM) or blockade of reabsorption with thapsigargin (1 microM) decreased the duration of RVD. 8. Prostaglandin E2 (PGE2, 5 microM) slightly delayed RVD, whereas leukotriene D4 (LTD4, 100 nM) and arachidonic acid (10 microM) reduced the duration of RVD. Blockade of phospholipase A2 by quinacrine (10 microM) inhibited RVD by 53 %. Common inhibition of PGE2 and LTD4 synthesis by ETYA (50 microM) or separate blockade of PGE2 synthesis by 1 microM indomethacin reduced the duration of RVD. Blockade of LTD4 synthesis by nordihydroguaiaretic acid (NDGA) did not produce any significant effect on cell swelling or subsequent RVD. 9. Staurosporine (1 microM), an inhibitor of protein kinases, inhibited RVD by 58 %. Taken together the experiments demonstrate that the RVD process is under the control of conductive pathways, extra- and intracellular Ca2+ ions, protein kinases, prostaglandins and leukotrienes.  (+info)

Acetylcholine-induced membrane potential changes in endothelial cells of rabbit aortic valve. (6/3001)

1. Using a microelectrode technique, acetylcholine (ACh)-induced membrane potential changes were characterized using various types of inhibitors of K+ and Cl- channels in rabbit aortic valve endothelial cells (RAVEC). 2. ACh produced transient then sustained membrane hyperpolarizations. Withdrawal of ACh evoked a transient depolarization. 3. High K+ blocked and low K+ potentiated the two ACh-induced hyperpolarizations. Charybdotoxin (ChTX) attenuated the ACh-induced transient and sustained hyperpolarizations; apamin inhibited only the sustained hyperpolarization. In the combined presence of ChTX and apamin, ACh produced a depolarization. 4. In Ca2+-free solution or in the presence of Co2+ or Ni2+, ACh produced a transient hyperpolarization followed by a depolarization. In BAPTA-AM-treated cells, ACh produced only a depolarization. 5. A low concentration of A23187 attenuated the ACh-induced transient, but not the sustained, hyperpolarization. In the presence of cyclopiazonic acid, the hyperpolarization induced by ACh was maintained after ACh removal; this maintained hyperpolarization was blocked by Co2+. 6. Both NPPB and hypertonic solution inhibited the membrane depolarization seen after ACh washout. Bumetanide also attenuated this depolarization. 7. It is concluded that in RAVEC, ACh produces a two-component hyperpolarization followed by a depolarization. It is suggested that ACh-induced Ca2+ release from the storage sites causes a transient hyperpolarization due to activation of ChTX-sensitive K+ channels and that ACh-activated Ca2+ influx causes a sustained hyperpolarization by activating both ChTX- and apamin-sensitive K+ channels. Both volume-sensitive Cl- channels and the Na+-K+-Cl- cotransporter probably contribute to the ACh-induced depolarization.  (+info)

Differences in the actions of some blockers of the calcium-activated potassium permeability in mammalian red cells. (7/3001)

1. The actions of some inhibitors of the Ca2+-activated K+ permeability in mammalian red cells have been compared. 2. Block of the permeability was assessed from the reduction in the net loss of K+ that followed the application of the Ca2+ ionophore A23187 (2 microM) to rabbit red cells suspended at a haematocrit of 1% in a low potassium solution ([K]0 0.12-0.17 mM) at 37 degrees C. Net movement of K+ was measured using a K+-sensitive electrode placed in the suspension. 3. The concentrations (microM +/- s.d.) of the compounds tested causing 50% inhibition of K+ loss were: quinine, 37 +/- 3; cetiedil, 26 +/- 1; the cetiedil congeners UCL 1269, UCL 1274 and UCL 1495, approximately 150, 8.2 +/- 0.1, 0.92 +/- 0.03 respectively; clotrimazole, 1.2 +/- 0.1; nitrendipine, 3.6 +/- 0.5 and charybdotoxin, 0.015 +/- 0.002. 4. The characteristics of the block suggested that compounds could be placed in two groups. For one set (quinine, cetiedil, and the UCL congeners), the concentration-inhibition curves were steeper (Hill coefficient, nH, > or = 2.7) than for the other (clotrimazole, nitrendipine, charybdotoxin) for which nH approximately 1. 5. Compounds in the first set alone became less active on raising the concentration of K+ in the external solution to 5.4 mM. 6. The rate of K+ loss induced by A23187 slowed in the presence of high concentrations of cetiedil and its analogues, suggesting a use-dependent component to the inhibitory action. This was not seen with clotrimazole. 7. The blocking action of the cetiedil analogue UCL 1274 could not be overcome by an increase in external Ca2+ and its potency was unaltered when K+ loss was induced by the application of Pb2+ (10 microM) rather than by A23187. 8. These results, taken with the findings of others, suggest that agents that block the red cell Ca2+-activated K+ permeability can be placed in two groups with different mechanisms of action. The differences can be explained by supposing that clotrimazole and charybdotoxin act at the outer face of the channel whereas cetiedil and its congeners may block within it, either at or near the K+ binding site that determines the flow of K+.  (+info)

Modulation of chloride, potassium and bicarbonate transport by muscarinic receptors in a human adenocarcinoma cell line. (8/3001)

1. Short-circuit current (I(SC)) responses to carbachol (CCh) were investigated in Colony 1 epithelia, a subpopulation of the HCA-7 adenocarcinoma cell line. In Krebs-Henseleit (KH) buffer, CCh responses consisted of three I(SC) components: an unusual rapid decrease (the 10 s spike) followed by an upward spike at 30 s and a slower transient increase (the 2 min peak). This response was not potentiated by forskolin; rather, CCh inhibited cyclic AMP-stimulated I(SC). 2. In HCO3- free buffer, the decrease in forskolin-elevated I(SC) after CCh was reduced, although the interactions between CCh and forskolin remained at best additive rather than synergistic. When Cl- anions were replaced by gluconate, both Ca2+- and cyclic AMP-mediated electrogenic responses were significantly inhibited. 3. Basolateral Ba2+ (1-10 mM) and 293B (10 microM) selectively inhibited forskolin stimulation of I(SC), without altering the effects of CCh. Under Ba2+- or 293B-treated conditions, CCh responses were potentiated by pretreatment with forskolin. 4. Basolateral charybdotoxin (50 nM) significantly increased the size of the 10 s spike of CCh responses in both KH and HCO3- free medium, without affecting the 2 min peak. The enhanced 10 s spike was inhibited by prior addition of 5 mM apical Ba2+. Charybdotoxin did not affect forskolin responses. 5. In epithelial layers prestimulated with forskolin, the muscarinic antagonists atropine and 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP, both at 100 nM) abolished subsequent 10 microM CCh responses. Following addition of p-fluoro hexahydro-sila-difenidol (pF-HHSiD, 10 microM) or pirenzepine (1 microM), qualitative changes in the CCh response time-profile also indicated a rightward shift of the agonist concentration-response curve; however, 1 microM gallamine had no effect. These results suggest that a single M3-like receptor subtype mediates the secretory response to CCh. 6. It is concluded that CCh and forskolin activate discrete populations of basolateral K+ channels gated by either Ca2+ or cyclic AMP, but that the Cl- permeability of the apical membrane may limit their combined effects on electrogenic Cl- secretion. In addition, CCh activates a Ba2+-sensitive apical K+ conductance leading to electrogenic K+ transport. Both agents may also modulate HCO3- secretion through a mechanism at least partially dependent on carbonic anhydrase.  (+info)

Potassium Channels Inhibitors on signaling pathway are available at Adooq Bioscience. Check Potassium Channels pathway , inhibitors reviews and assay information.
Combined Use of MC4PC, MDL-QSAR, BioEpisteme, Leadscope PDM, and Derek for Windows Software to Achieve High-Performance, High-Confidence Mode of Action-Based Predictions of Chemical Carcinogenesis in Rodents. Authors: Edwin J. Matthews; Naomi L. Kruhlak; R. Daniel Benz; Joseph F. Contrera; Carol A. Marchant; Chihae Yang. Journal: To ...
Potassium channel blocker information including symptoms, causes, diseases, symptoms, treatments, and other medical and health issues.
... : Dalfampridine, or Ampyra, is a potassium channel blocker that is shown to improve visual function, motor skills and relieve fatigue in MS patients.
TY - JOUR. T1 - Short-term effects of glipizide (an adenosine triphosphate-sensitive potassium channel inhibitor) on cardiopulmonary hemodynamics and global oxygen transport in healthy and endotoxemic sheep. AU - Lange, Matthias. AU - Szabo, Csaba. AU - Van Aken, Hugo. AU - Williams, William. AU - Traber, Daniel L.. AU - Daudel, Fritz. AU - Bröking, Katrin. AU - Salzman, Andrew L.. AU - Bone, Hans Georg. AU - Westphal, Martin. PY - 2006/11. Y1 - 2006/11. N2 - In severe sepsis and septic shock, hemodynamic support is often complicated by a tachyphylaxis against exogenous catecholamines. Because activation of adenosine triphosphate (ATP)-sensitive potassium (KATP) channels plays a pivotal role in the pathogenesis of hyperdynamic vasodilatory shock, we hypothesized that it may be beneficial to administer a specific KATP channel inhibitor to prevent, or at least attenuate, hemodynamic dysfunction in sepsis. The present study was designed as a prospective and controlled laboratory experiment to ...
Stroke causes CNS injury associated with strong fast microglial activation as part of the inflammatory response. In rat models of stroke, sulphonylurea receptor blockade with glibenclamide reduced cerebral edema and infarct volume. We postulated that glibenclamide administered during the early stages of stroke might foster neuroprotective microglial activity through ATP-sensitive potassium (KATP) channel blockade. We found in vitro that BV2 cell line showed upregulated expression of KATP channel subunits in response to pro-inflammatory signals and that glibenclamide increases the reactive morphology of microglia, phagocytic capacity and TNFα release. Moreover, glibenclamide administered to rats 6, 12 and 24 h after transient Middle Cerebral Artery occlusion improved neurological outcome and preserved neurons in the lesioned core three days after reperfusion. Immunohistochemistry with specific markers to neuron, astroglia, microglia and lymphocytes showed that resident amoeboid microglia are the ...
Chlorpromazine hydrochloride is a dopamine and potassium channel inhibitor with IC50 of 6.1 and 16 μM for nward-rectifying K+ currents and time-independent outward currents Buy Potassium Channel inhibitor Chlorpromazine hydrochloride (Sonazine) from AbMole BioScience.
Chlorpromazine (Sonazine) is a dopamine and potassium channel inhibitor with IC50 of 6.1 and 16 μM for inward-rectifying K+ currents and time-independent outward currents Find all the information about Chlorpromazine (Sonazine) for cell signaling research.
Dalfampridine is a potassium channel blocker. Dalfampridine is used to improve walking in patients with multiple sclerosis (MS). Dalfampridine may also be used for purposes not listed in this medication guide.
BioAssay record AID 623912 submitted by Johns Hopkins Ion Channel Center: SAR Analysis for the identification of inhibitors of the two-pore domain potassium channel KCNK9 - Selectivity assay against KCNK3: FluxOR Assay CRC 2.
BioAssay record AID 588761 submitted by Johns Hopkins Ion Channel Center: SAR Analysis for the identification of selective inhibitors of the two-pore domain potassium channel KCNK9 in KCNQ2 expressing cells: FluxOR Assay CRC.
Two new benzophenones, acredinones A (1) and B (2), were isolated from a marine-sponge-associated Acremonium sp. fungus. Their chemical structures were elucidated on the interpretation of spectroscopic data. The structure of 1 was confirmed by palladium-catalyzed hydrogenation, followed by spectroscopic data analysis. Acredinones A (1) and B (2) inhibited the outward K+ currents of the insulin secreting cell line INS-1 with IC50 values of 0.59 and 1.0 mu M, respectively ...
ID KCNH2_CANLF Reviewed; 1158 AA. AC Q9TSZ3; O02719; O18820; DT 28-NOV-2002, integrated into UniProtKB/Swiss-Prot. DT 01-MAY-2000, sequence version 1. DT 27-SEP-2017, entry version 129. DE RecName: Full=Potassium voltage-gated channel subfamily H member 2; DE AltName: Full=Ether-a-go-go-related gene potassium channel 1; DE Short=DERG; DE Short=ERG-1; DE Short=Eag-related protein 1; DE Short=Ether-a-go-go-related protein 1; DE Short=c-ERG; DE AltName: Full=Voltage-gated potassium channel subunit Kv11.1; GN Name=KCNH2; Synonyms=CERG, ERG; OS Canis lupus familiaris (Dog) (Canis familiaris). OC Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; OC Mammalia; Eutheria; Laurasiatheria; Carnivora; Caniformia; Canidae; OC Canis. OX NCBI_TaxID=9615; RN [1] RP NUCLEOTIDE SEQUENCE [MRNA]. RC TISSUE=Heart; RX PubMed=11417212; DOI=10.1007/s004240100524; RA Zehelein J., Zhang W., Koenen M., Graf M., Heinemann S.H., Katus H.A.; RT "Molecular cloning and expression of cERG, the ether a ...
Cerebellar granule neurons (CGNs) are one of the most populous cells in the mammalian brain. They express an outwardly rectifying potassium current, termed a
Effective, safe, and tolerable pharmacological treatment for atrial fibrillation (AF) remains an unmet need. The latest medication to reach the market for intravenous cardioversion was the combined sodium and potassium channel inhibitor vernakalant, however not yet available in the United States. Vernakalant terminated ≈50% of episodes of AF lasting ,7 days in randomized controlled studies, with its highest conversion rate during the first few days while after 8 to 45 days of AF, the conversion rate was ,10%, which was not statistically different from that of placebo.1,2. If lasting for ,24 hours, AF promotes further progression of the disease-a phenomenon described as AF begets AF.3 If atrial remodeling continues, AF often progresses to more sustained forms and becomes more resistant to both pharmacological and nonpharmacological treatments, including ablation.4-6 Among contributing factors, an increased influx of calcium seems to promote fibrosis development and remodeling.7. Three subtypes ...
TY - JOUR. T1 - Expression of intermediate-conductance, Ca2+-activated K+ channel (KCNN4) in H441 human distal airway epithelial cells. AU - Wilson, Stuart M.. AU - Brown, Sean G.. AU - McTavish, Niall. AU - McNeill, R. P.. AU - Husband, E. M.. AU - Inglis, Sarah K.. AU - Olver, Richard E.. AU - Clunes, M. T.. PY - 2006/6/9. Y1 - 2006/6/9. N2 - Electrophysiological studies of H441 human distal airway epithelial cells showed that thapsigargin caused a Ca2+-dependent increase in membrane conductance (GTot) and hyperpolarization of membrane potential (Vm). These effects reflected a rapid rise in cellular K+ conductance (GK) and a slow fall in amiloride-sensitive Na+ conductance (GNa). The increase in GTot was antagonized by Ba2+, a nonselective K+ channel blocker, and abolished by clotrimazole, a KCNN4 inhibitor, but unaffected by other selective K+ channel blockers. Moreover, 1-ethyl-2-benzimidazolinone (1-EBIO), which is known to activate KCNN4, increased GK with no effect on GNa. RT-PCR-based ...
The effects of 4-aminopyridine (4AP) on the extracellularly recorded nerve terminal action potential (NTAP) and end-plate potential were studied at the frog neuromuscular junction. An in-depth analysis of the time course of the NTAP was performed in the presence and absence of extracellular Ca++. Low concentrations (5 X 10(-6) M) of 4AP produced no significant alterations in the time course of the NTAP, yet increased quantal content of the end-plate potential 2-fold. In contrast, high concentrations (5 X 10(-4) M) of 4AP prolonged the duration of the NTAP by selectively flattening the K+ slope of the NTAP and increased the quantal content of the end-plate potential. It is concluded that both potassium channel blockade and facilitation of transmitter release by 4AP can be demonstrated in this preparation, and that it is possible to separate these actions by varying the concentration of 4AP. Interpretation of these data suggests that there is a second site or mechanism of action by which 4AP ...
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Gianulis EC et. al. (2011) Rescue of aberrant gating by a genetically encoded PAS (Per-Arnt-Sim) domain in several long QT syndrome mutant human ether-á-go-go-related gene potassium channels.. [^] ...
Background and Aim: Multiple sclerosis (MS) is considered as a common inflammatory disease of the human central nervous system (CNS). 4 amino pyridine (4-AP), a potassium channel blocker, is used widely in MS treatment to reduce fatigue and cachexia often experienced by the patients. The objective of this study was to get a better ...
Anti arrhythmic drugs are classified into four main classes. Class I - Sodium channel blockers(act on Phase 0) Class II - Beta blockers(act on phase 4) Class III- Potassium channel blockers(act on phase 3) Class IV - Calcium channel blockers(act …. Read more ». ...
High purity synthetic Margatoxin (#STM-325) (CAS 145808-47-5) is a biologically active Kv1.3 and Kv1.6 channel blocker. 100% net peptide content. New lots are biologically tested. Free samples available. Lyophilized powder. Worldwide shipping at room temp. Alomone Labs is your top supplier for K+ channel research!
Abbott Laboratories (now AbbVie) and Icagen (now Neusentis) were developing small-molecule ion channel modulators for the treatment of chronic pain and
Seachem Flourish Potassium 250ml Flourish Potassium Product Description Flourish Potassium contains 50,000 mg/L of potassium suitable for the natural planted aquarium. Potassium is one of several elements that are vitally important to maintaining a vigorous level of growth in a planted aquarium. Potassium can become de
This series contains the 3 test suite patches that had to be dropped from the v6 series during merge with the block tree: v6: https://lists.gnu.org/archive/html/qemu-devel/2016-03/msg04935.html Changed in v7: - Avoid setting TEST_IMG_FILE when IMGPROTO=file in common.rc for traditional (not --image-opts) variable setup Daniel P. Berrange (3): block: add support for --image-opts in block I/O tests block: add support for encryption secrets in block I/O tests block: enable testing of LUKS driver with block I/O tests tests/qemu-iotests/004 , 2 +- tests/qemu-iotests/012 , 2 +- tests/qemu-iotests/039.out , 20 +++++------ tests/qemu-iotests/048 , 22 ++++++++---- tests/qemu-iotests/048.out , 6 ++-- tests/qemu-iotests/052 , 4 +++ tests/qemu-iotests/052.out , 4 +++ tests/qemu-iotests/100 , 7 ++++ tests/qemu-iotests/100.out , 14 ++++++++ tests/qemu-iotests/common , 15 +++++++- tests/qemu-iotests/common.config , 21 ++++++++++-- tests/qemu-iotests/common.filter , 3 +- tests/qemu-iotests/common.rc , 74 ...
[107 Pages Report] Check for Discount on Global 2-Aminopyridine Market Professional Survey Report 2016 report by QYResearch Group. This report Mainly covers the following product types The segment...
Describes how the potassium test is used, when a potassium test is requested, and what the results of a potassium test might mean
The protein encoded by this gene is part of a potentially heterotetrameric voltage-independent potassium channel that is activated by intracellular calcium. Activation is
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As may be agreed by consumer and manufacturer, additional requirements to the quality of potassium tetrachloroplatinate (II) and potassium hexachloroplatinate (IV) can be established.. Back. ...
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Looking for online definition of Tandem pore domain potassium channel in the Medical Dictionary? Tandem pore domain potassium channel explanation free. What is Tandem pore domain potassium channel? Meaning of Tandem pore domain potassium channel medical term. What does Tandem pore domain potassium channel mean?
TY - JOUR. T1 - The ATP-sensitive potassium-channel inhibitor glibenclamide improves outcome in an ovine model of hemorrhagic shock. AU - Maybauer, Dirk M.. AU - Salsbury, John R.. AU - Westphal, Martin. AU - Maybauer, Marc O.. AU - Salzman, Andrew L.. AU - Szabo, Csaba. AU - Westphal-Varghese, Beena B.. AU - Traber, Lillian D.. AU - Traber, Daniel L.. PY - 2004/10. Y1 - 2004/10. N2 - This study was designed as a prospective laboratory experiment to evaluate the effects of the ATP-sensitive potassium-channel inhibitor glibenclamide on hemodynamics and end-organ function in an ovine model of hemorrhagic shock. Twenty-four adult sheep were anesthetized and surgically prepared to measure hemodynamics of the systemic and pulmonary circulation. The anterior surface of the abdominal aorta was exposed at a location 6 cm superior to the iliac bifurcation. After a 60-min period of stabilization, this location was punctured with a 14-G needle. To induce a hemorrhagic hypotension (mean arterial pressure ...
Antibodies for proteins involved in positive regulation of voltage-gated potassium channel activity involved in ventricular cardiac muscle cell action potential repolarization pathways, according to their Panther/Gene Ontology Classification
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 ...
Multiple sclerosis (MS) can be an autoimmune disease seen as a chronic swelling in the central anxious program (CNS) which leads to permanent neuronal harm and substantial impairment in individuals. Since these constructions were connected with a more serious disease course it is rather vital that you gain insight in to the system of induction their exact function and medical significance. Mechanistic research in individuals are limited. Nevertheless a few research in the 6-Shogaol MS pet model experimental autoimmune encephalomyelitis (EAE) recapitulate TLO development in the CNS and 6-Shogaol offer new understanding into CNS TLO features development and function. This review summarizes what we realize up to now about CNS TLOs in MS and what weve learned all about them from EAE versions. It also shows the areas that may need further experimental are we are simply starting to understand and measure the trend of CNS TLOs. cytotoxic injury and indirect systems e.g. by inducing activation of ...
In this paper, we investigated the interaction of hanatoxin with the Shaker Kv channel. In contrast to the inhibitory actions of the toxin on Kv2.1 channels investigated in previous studies (Swartz and MacKinnon, 1997a,b; Li-Smerin and Swartz, 1998, 2000, 2001; Lee et al., 2003; Wang et al., 2004; Phillips et al., 2005; Alabi et al., 2007; Bosmans et al., 2008), our results show that hanatoxin facilitates opening of the Shaker Kv channel by interacting with the paddle motif (Figs. 1-3), stabilizing the voltage sensor in the activated state (Fig. 5), and influencing the final opening transition to stabilize the open state of the pore (Figs. 4 and 6). Although the effects of hanatoxin on the G-V relations (Figs. 1 and 2), the kinetics of channel closure (Figs. 1 and 4), and the ILT channel (Fig. 6) could in part be explained by effects on the final opening transition in Shaker, the pronounced effects of the toxin on gating currents (Fig. 5) suggest that early transitions in the voltage sensors are ...
The present study evaluated the contribution of cGMP-dependent versus cGMP-independent pathways in mediating the effects NO on K+ channel activity and vascular tone in renal arterioles. The results indicate that NO selectively enhances the NPo of a large-conductance (195±9 pS) K+ channel in renal VSM cells in a concentration-dependent manner. NO had no significant effect on the activity of the two smaller conductance channels in renal VSM cells that were previously identified as a small-conductance, apamin-sensitive, KCa channel33 and the 4-aminopyridine-sensitive delayed rectifier channel.28 34 35 36 The K+ channel activated by NO is voltage-sensitive and is blocked by TEA and iberiotoxin which are selective inhibitors of the KCa channel.37 38 39 Thus, the present findings indicate that NO activates KCa channels in renal VSM cells, and they are consistent with the results of recent studies with smooth muscle cells isolated from other tissues.6 7 9 11 13 15 Additional experiments were performed ...
This enabled them to draw conclusions about its mechanism of action, which they describe in the current issue of "Nature Communications". Neurons conduct information by way of electrical impulses through our body. Potassium channels are a key component of this electrical circuit and are controlled either by an electrical impulse or through signaling molecules. In man, the dysfunction of the so-called HCN potassium channels is associated with neurological disorders such as epilepsy and depression. Prof. Henning Stahlbergs team at the Biozentrum of the University of Basel has now elucidated the full structure of a bacterial counterpart of this type of potassium channel, which has provided new insights into its functioning.. ...
Eight of these oxygen atoms surround each potassium ion acts as a perfect replacement for the normal layer of water molecules. Sodium ions, are slightly smaller in size
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.
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4SC was developing small molecule openers of the human Ca2+-activated and voltage-dependent potassium channel BKCa as potential therapeutics for the treatment
Anti arrhythmic drugs are classified into four main classes.. Class I - Sodium channel blockers(act on Phase 0). Class II - Beta blockers(act on phase 4). Class III- Potassium channel blockers(act on phase 3). Class IV - Calcium channel blockers(act on phase 2). ...
... , Authors: Dessen P. Published in: Atlas Genet Cytogenet Oncol Haematol.
Kv1.2 Potassium Channel information including symptoms, causes, diseases, symptoms, treatments, and other medical and health issues.
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Two common potassium channel blockers are Doxapram and GAL-021. Both act on potassium channels in Carotid Bodies. These cells ... Doxapram blocks leak potassium channels in the Tandom pore domain family of potassium channels while GAL-021 blocks BK channels ... Analeptics can act as potassium channel blockers, ampakines, and serotonin receptor agonists, and adenosine antagonism. ... Blocking the potassium channels on the membranes of these cells effectively depolarizes the membrane potential, which in turn ...
The toxin is known for its ability to act as a specific Kv4 channel blocker, and thereby reducing the A-type potassium current ... Bougis, PE; Martin-Eauclaire, MF (25 June 2015). "Shal-type (Kv4.x) potassium channel pore blockers from scorpion venoms". ... By blocking specifically the Kv4 channels, AmmTX3 reduces the A-type potassium current through these channels almost completely ... "Potassium Channels Blockers from the Venom of Androctonus mauretanicus mauretanicus". Journal of Toxicology. 2012: 103608. doi: ...
Bergapten has also been implicated as a potassium channel blocker; in one case study, a patient who consumed four litres of ...
The potassium channel blocker tetraethylammonium (TEA) has been shown to reverse the effects of tubocurarine. It is thought to ... "d-Tubocurarine (Prototype Nondepolarizing Neuromuscular Blocker)". Tulane University. Retrieved 4 May 2015. Bowman WC, Webb SN ...
... is a potassium channel blocker. Paxilline is a toxic, tremorgenic indole alkaloid produced by Penicillium paxilli . ...
It is a potassium channel blocker. It has been found to have teratogenic effects in rats. Wiesfeld AC, Crijns HJ, Bergstrand RH ...
A potent new potassium channel blocker". Biophys J. 22 (3): 507-12. doi:10.1016/s0006-3495(78)85503-9. PMC 1473482 . PMID ... Amifampridine works by blocking potassium channel efflux in nerve terminals so that action potential duration is increased. ... Ca2+ channels can then be open for a longer time and allow greater acetylcholine release to stimulate muscle at the end plate. ... Because it affects voltage-gated ion channels, it is contraindicated in people with long QT syndrome and in people taking a ...
... also acts as a potassium channel blocker (Kv11.1 encoded by the gene hERG). Since its active metabolite is not a potassium ... channel blocker, no cardiotoxicity is associated with fexofenadine.[3] Toxicity is possible after years of continued use with ...
Walking : dalfampridine (ampyra) is a broad-spectrum potassium channel blocker. It is approved by the FDA to treat walking ...
"Compared toxicity of the potassium channel blockers, apamin and dendrotoxin". Toxicology. 104 (1-3): 47-52. doi:10.1016/0300- ... Here it inhibits small-conductance Ca2+-activated K+ channels (SK channels) in neurons. These channels are responsible for the ... SK channel blockers may have a therapeutic effect on Parkinson's disease. Dopamine, which is depleted in this disease, will be ... Castle NA, Haylett DG, Jenkinson DH (Feb 1989). "Toxins in the characterization of potassium channels". Trends in Neurosciences ...
Gao, B; Peigneur, S; Tytgat, J; Zhu, S (2010). "A potent potassium channel blocker from Mesobuthus eupeus scorpion venom". ... In contrast, BeKm-1 specifically inhibits hERG channels, which are potassium channels critical to maintaining normal electrical ... but showed no effects on various other potassium channels tested. Inhibitors of sodium channels have also been found in this ... Sanguinetti MC, Tristani-Firouzi M (March 2006). "hERG potassium channels and cardiac arrhythmia". Nature. 440 (7083): 463-9. ...
It is a potent blocker of calcium-activated potassium channels. Both verruculogen and its isoprenyl derivative fumitremorgin A ...
Bergapten has also been implicated as a potassium channel blocker; in one case study, a patient who consumed four liters of ... the outside of the fruit under running water to get an emulsion channeled into centrifuges for separating the essence from the ...
... a Selective Blocker of A-Type Potassium Channels". Biochemistry. 36: 2763-71. doi:10.1021/bI9628432. PMID 9062103.. ... and iberiotoxin with potassium channels: selectivity between voltage-gated and Maxi-K channels". Proteins. 52 (2): 146-54. doi: ... "Mechanisms of maurotoxin action on Shaker potassium channels". Biophys. J. 79 (2): 776-87. doi:10.1016/S0006-3495(00)76335-1. ... This block occurs as the Asn 30 on the CTX interacts with the Asp 381 on the K+ channel.[9] The blockade of K+ channels by the ...
... is a potassium-channel blocker like Class III antiarrhythmic compounds. This compounds can bind to potassium ... channels and delays phase 3 repolarization. These electrophysiological changes decrease the sensitiveness of cells to ...
Judge S, Bever C (2006). "Potassium channel blockers in multiple sclerosis: neuronal Kv channels and effects of symptomatic ... 4-AP works as a potassium channel blocker. Electrophysiologic studies of demyelinated axons show that augmented potassium ... Potassium channel blockade reverses this effect. A study has shown that 4-AP is a potent calcium channel activator and can ... It is used as a research tool in characterizing subtypes of the potassium channel. It has also been used as a drug, to manage ...
"Potassium channel blockers from the venom of the Brazilian scorpion Tityus serrulatus". Toxicon. 119: 253-265. doi:10.1016/j. ... It seems likely that TsPep2 has inhibitory actions on potassium channels, based on its sequence similarities in the C-terminal ... beta sheet with the potassium channel inhibitory alpha family (α-KTX) and on its similarities in the patterns of disulfide ... "Structure function relationship of K+ion channel toxins:from cloning to functional characterization". Leuve, Belgium: Isabelle ...
These potassium channel blockers delay ventricular repolarization and prolong action potential duration (APD; the prolongation ... Most anti-arrhythmic medications exert their effects by decreasing the permeability of potassium ion channels (IKr) in heart ... unlike pure IKr channel blockers, it is self-limited (due to the decreased permeability of INa-L and ICa-L). This is similar to ... but predominantly the INa-L ion channel . By decreasing the ion permeability of these channels, HBI-3000 slightly prolongs APD ...
Valverde P, Kawai T, Taubman MA (June 2005). "Potassium channel-blockers as therapeutic agents to interfere with bone ... Calcium entry through the CRAC channel is promoted by potassium efflux through the Kv1.3 and KCa3.1 potassium channels. ... Potassium channels represent the most complex class of voltage-gated ion channels from both functional and structural ... "A potassium-channel toxin from the sea anemone Bunodosoma granulifera, an inhibitor for Kv1 channels. Revision of the amino ...
Valverde P, Kawai T, Taubman MA (June 2005). "Potassium channel-blockers as therapeutic agents to interfere with bone ... Calcium entry through the CRAC channel is promoted by potassium efflux through the Kv1.3 and KCa3.1 potassium channels. ... "A C-terminally amidated analogue of ShK is a potent and selective blocker of the voltage-gated potassium channel Kv1.3". FEBS ... Xu J, Koni PA, Wang P, Li G, Kaczmarek L, Wu Y, Li Y, Flavell RA, Desir GV (March 2003). "The voltage-gated potassium channel ...
In addition, it is a potent blocker of voltage-sensitive potassium channels. MCD peptide is a component of bumblebee ( ... It binds to several subclasses of voltage-gated potassium channels (Kv channels), including Kv1.1, Kv1.6, and less potently to ... By blocking potassium channels, the MCD peptide can increase the duration of action potentials and increase neuronal ... This toxicity is caused by the blockage of voltage-gated potassium channels by the MCD peptide. However, there is no toxicity ...
... is a first-generation potassium channel blocker, sulfonylurea oral hypoglycemic medication. This drug may be used ...
1997). "Tedisamil is a potent blocker of ATP-sensitive potassium channels in cardiac muscle". Exp Clin Cardiol (2): 37-40. ... 2000). "Antianginal and anti-ischemic efficacy of tedisamil, a potassium channel blocker". Heart. 83: 167-171. doi:10.1136/ ... Tedisamil also appears to provide specific, single channel blocking of IK-ATP at high concentrations. As the potassium channels ... Tedisamil blocks multiple types of potassium channels in the heart resulting in slowed heart rate. While the effects of ...
... a potassium channel blocker from the scorpion". Protein Science. 14 (4): 1025-1038. doi:10.1110/ps.041131205. PMC 2253457 . ... "Potassium channel toxin alpha-KTx 12.4". PubMed Protein Database. UniProtKB/Swiss-Prot: P0C8L1.1. "Potassium channel toxin ... Thus, butantoxin has the capacity to interact with a variety of K+ channels and has a variable affinity for each K+ channel. ... Butantoxin reversibly blocks the voltage-gated K+ channels Shaker B and Kv1.2, and the Ca2+-activated K+ channels KCa 1.1 and ...
This toxin is a selective blocker of BK channels, calcium-activated potassium channels. Limbatustoxin is purified from the ... also called maxi-K channels, slo1 or BK (big potassium) channels. These channels play an important role in the excitability of ... Yu, M, Liu, SL, Sun, PB, Pan, H, Tian, CL, & Zhang, LH (2016). "Peptide toxins and small-molecule blockers of BK channels". ... This structure is important for binding to BK channels. Limbatustoxin is highly selective for calcium-activated potassium ...
But if the γ2 is expressed with α1 and β2 the sensitivity is low and channel conductance is high.[7] γ2 subunit has to be ... Bromide compounds (e.g., lithium bromide, potassium bromide, sodium bromide). *Carbamazepine. *Chloralose ... Upon binding, it triggers the GABAA receptor to open its chloride channel to allow chloride ions into the neuron, making the ... The channel conductance is not higher in the presence of benzodiazepine and GABA than the conductance with the presence of only ...
PROTEINASE INHIBITOR HOMOLOGUES AS POTASSIUM CHANNEL BLOCKERS. *DOI: 10.2210/pdb1DEN/pdb. *Classification: VENOM(POTASSIUM ... Proteinase inhibitor homologues as potassium channel blockers.. Lancelin, J.M., Foray, M.F., Poncin, M., Hollecker, M., Marion ... We report here the NMR structure of dendrotoxin I, a powerful potassium channel blocker from the venom of the African Elapidae ... We report here the NMR structure of dendrotoxin I, a powerful potassium channel blocker from the venom of the African Elapidae ...
Potassium Channels Blockers from the Venom of Androctonus mauretanicus mauretanicus. Marie-France Martin-Eauclaire and Pierre E ... Marie-France Martin-Eauclaire and Pierre E. Bougis, "Potassium Channels Blockers from the Venom of Androctonus mauretanicus ...
Bupivacaine is an effective potassium channel blocker in heart.. Courtney KR1, Kendig JJ. ... and blocks two potassium conductances, IK and IK1. The effective concentrations, particularly for IK, are similar to those ...
WebMD provides information about interactions between Stavzor Oral and sodium-channel-blocker-potassium-channel-blocker- ... Lacosamide/Sodium Channel Blockers; Potassium Channel Blockers Interactions. This information is generalized and not intended ...
Potassium Channel Blockers. Class Summary. Blocking voltage-dependent potassium channels prolongs presynaptic cell membrane ... a voltage-dependent potassium channel blocker, is indicated for treatment of LEMS. Blocking voltage-dependent potassium ... Complete reversal of Lambert-Eaton myasthenic syndrome synaptic impairment by the combined use of a K+ channel blocker and a ... Increases intracellular calcium concentrations in nerve endings by blocking voltage-dependent potassium channels. The increased ...
Kv1.5 Potassium Channel Blockers Overview. Kv1.5 Potassium Channel Blockers Disease Associated. Kv1.5 Potassium Channel ... Kv1.5 Potassium Channel Blockers Filed and Phase III Products. Comparative Analysis. Kv1.5 Potassium Channel Blockers Phase II ... Kv1.5 Potassium Channel Blockers Assessment by Molecule Type. Kv1.5 Potassium Channel Blockers Assessment by Stage and Molecule ... Kv1.5 Potassium Channel Blockers Assessment by Molecule Type. Kv1.5 Potassium Channel Blockers Assessment by Stage and Molecule ...
Potassium channel blockers are agents which interfere with conduction through potassium channels. Potassium channel blockers ... Sulfonylureas come under the class of ATP-sensitive potassium channel blockers. Dalfampridine, A potassium channel blocker has ... Potassium channel Potassium channel opener Lenz TL, Hilleman DE (July 2000). "Dofetilide, a new class III antiarrhythmic agent ... "Potassium channel blockers in multiple sclerosis: neuronal Kv channels and effects of symptomatic treatment". Pharmacol. Ther. ...
Conformational flexibility in the binding surface of the potassium channel blocker ShK.. Sher I1, Chang SC, Li Y, Chhabra S, ... Conformational flexibility in the binding surface of the potassium channel blocker ShK ... Conformational flexibility in the binding surface of the potassium channel blocker ShK ... Conformational flexibility in the binding surface of the potassium channel blocker ShK ...
... Dr. Shi discusses the potential of PCB?s as a ... Thread: Potassium Channel Blockers to Restore Impulse Conduction in SCI ? Dr. Riyi Shi ... 2003). The use of the potassium channel activator riluzole to test whether potassium. By Wise Young in forum SCI (Related) ... Channel blockers as 4AP can help but they can affect other body functions (heart rate) apparently...not sure.... never tested. ...
It is a potassium channel blocker that inhibits both transient outward (1to) and delayed rectifier (1k) potassium currents.1 2 ... OBJECTIVE To determine the efficacy and safety of the potassium channel blocker tedisamil versus placebo in the treatment of ... Lipid lowering agents, aspirin, nitrates, β blockers, and calcium channel blockers all have a role to play, the latter three ... Under suitable circumstances, nitrates, β blockers, and calcium channel blockers can be effective, but there is a good deal of ...
Antihypertensives: Potassium-sparing diuretics. *Antihypertensives: Dihydropyridine calcium channel blockers. *Show All. * ... Antihypertensives: Dihydropyridine calcium channel blockers. Class Summary. This and other calcium channel blockers ( ... Calcium ion influx inhibitor (slow-channel blocker or calcium ion antagonist) that selectively inhibits transmembrane influx of ... Antihypertensives: Potassium-sparing diuretics. Class Summary. One DOC to treat hypertension associated with 17-hydroxylase ...
Thread: Potassium Channel Blockers to Restore Impulse Conduction in SCI ? Dr. Riyi Shi ... Potassium Channel Blockers to Restore Impulse Conduction in SCI ? Dr. Riyi Shi ... 2003). The use of the potassium channel activator riluzole to test whether potassium. By Wise Young in forum SCI (Related) ... 2003). A comparison of the antinociceptive effects of voltage-activated Na(+) channel blockers in two rat models of neuropathic ...
Potassium channel blocker information including symptoms, causes, diseases, symptoms, treatments, and other medical and health ... Introduction: Potassium channel blocker. Description of Potassium channel blocker. Potassium channel blocker: A class of drugs ... Potassium channel *Potassium *Channel *Blocker Terms associated with Potassium channel blocker:. The following terms can be ... used for Potassium channel blocker. *ion channel blocker Source: CRISP Interesting Medical Articles:. *Symptoms of the Silent ...
Interaction between selected sodium and potassium channel blockers in guinea pig papillary muscle.. L Wang, N Chiamvimonvat and ... Interaction between selected sodium and potassium channel blockers in guinea pig papillary muscle.. L Wang, N Chiamvimonvat and ... Interaction between selected sodium and potassium channel blockers in guinea pig papillary muscle.. L Wang, N Chiamvimonvat and ... In this study, the interactions between the prolongation of action potential duration (APD) by a potassium channel blocker and ...
KV3.1 blockers can serve as modulators of the rate of action potential firing in neurons with high rates of firing such as ... Benzenesulfonamides act as open-channel blockers on KV3.1 potassium channel. ... Benzopyran sulfonamides as Kv1.5 potassium channel blockers. Bioorg Med Chem Lett 17:3271-3275CrossRefPubMedGoogle Scholar ... The Shaw-Related Potassium Channel Gene, Kv3.1, on Human Chromosome-11, Encodes the Type-L K+ Channel in T-Cells. J Biol Chem ...
ATP-Sensitive Potassium Channel Blocker HMR 1883 Reduces Mortality and Ischemia-Associated Electrocardiographic Changes in Pigs ... ATP-Sensitive Potassium Channel Blocker HMR 1883 Reduces Mortality and Ischemia-Associated Electrocardiographic Changes in Pigs ... ATP-Sensitive Potassium Channel Blocker HMR 1883 Reduces Mortality and Ischemia-Associated Electrocardiographic Changes in Pigs ... ATP-Sensitive Potassium Channel Blocker HMR 1883 Reduces Mortality and Ischemia-Associated Electrocardiographic Changes in Pigs ...
Discovery, characterization, and effects on renal fluid and electrolyte excretion of the Kir4.1 potassium channel pore blocker ... Discovery, characterization, and effects on renal fluid and electrolyte excretion of the Kir4.1 potassium channel pore blocker ... Discovery, characterization, and effects on renal fluid and electrolyte excretion of the Kir4.1 potassium channel pore blocker ... Discovery, characterization, and effects on renal fluid and electrolyte excretion of the Kir4.1 potassium channel pore blocker ...
Potassium Channel Blockers - Antiarrhythmic Drugs & boost your knowledge! Study for your classes, USMLE, MCAT or MBBS. Learn ... Class 3: Potassium Channel Blockers - Antiarrhythmic Drugs The main role of antiarrhythmic agents is to prevent the occurrence ... Author of lecture Group 3: Potassium Channel Blockers - Antiarrhythmic Drugs. Pravin Shukle, MD. ... The lecture Group 3: Potassium Channel Blockers - Antiarrhythmic Drugs by Pravin Shukle, MD is from the course Cardiovascular ...
Mesh term Potassium Channel Blockers. Browse to parent terms:. Cardiovascular Agents. Membrane Transport Modulators. ... A class of drugs that act by inhibition of potassium efflux through cell membranes. Blockade of potassium channels prolongs the ...
Taken together, our data further supports and implicates the role of potassium channels in conduction loss and its therapeutic ... Furthermore, we have also provided the critical evidence to confirm the unmasking of potassium channels following mechanical ... In addition, we also have confirmed that 4-AP-3-MeOH is indeed an effective blocker of I(A) based on patch-clamp studies using ... Novel potassium channel blocker, 4-AP-3-MeOH, inhibits fast potassium channels and restores axonal conduction in injured guinea ...
Do potassium channel blockers affect the resting membrane potential? If they block the resting state "leak" potassium channels ... Potassium channels are necessary for repolarization *Potassium channels participate in controlling the concentration gradient ... But there are many different potassium channels. You may be thinking of blocking the delayed rectifier potassium channel, which ... I am reading about scorpion venoms and toxins for my bio class and they appear to have a variety of potassium channel blockers ...
Medications to treat AFib include beta-blockers, blood thinners, and heart rhythm drugs. AFib medications can cause side ... Sodium Channel Blockers, for example, procainamide, disopyramide, quinidine, and flecainide (Tambocor).. *Potassium Channel ... Sodium and potassium channel blockers are two main types of drugs used specifically to treat the chaotic electrical activity ... For a list of common and less severe side effects of these drugs, please read our Beta-Blocker, Calcium Channel Blocker, ...
... ion channels, potassium channels, benadryl, diphenhydramine, mepyramine, pyrilamine, dup 996, xe-991, dup996, linopirdine, ... Potassium Channel KCNQ blockers tagged: pharmacology, activators-inhibitors, ... Potassium Channel KCNQ blockers. https://www.scienceslides.com/thumb/,bound method SlideThumb.key of ,model.SlideThumb object ...
Potassium channel blockers. These drugs work by reducing the electrical signals in your heart that cause symptoms of AFib. ... Calcium channel blockers. These drugs work like beta blockers. They decrease heart rate. Calcium channel blockers for AFib are ... calcium channel blockers. Digoxin (Lanoxin) Digoxin works by helping to control electrical currents between the upper and lower ... Other calcium channel blockers are peripherally acting. They may lower blood pressure, but they arent helpful for AFib heart ...
Dofetilide blocks only IKr with no relevant block of the other repolarizing potassium currents (e.g., IKs, IK1). At clinically ... relevant concentrations, Dofetilide has no effect on sodium channels (associated with Class I effect), adrenergic alpha- ...
  • The lecture Group 3: Potassium Channel Blockers - Antiarrhythmic Drugs by Pravin Shukle, MD is from the course Cardiovascular Pharmacology. (lecturio.com)
  • Evaluation in the EuroFins Lead Profiling panel of 64 GPCRs, ion-channels, and transporters for off-target activity of ML418 revealed a relatively clean ancillary pharmacology. (nebraska.edu)
  • Because potassium channels are the most represented by the superfamily of ion channels, the systematization of the relevant information on the molecules acting on them is an interesting and important problem in Bioorganic Chemistry and Pharmacology. (ibch.ru)
  • In 2017, the global Potassium Channel Blocker market size was xx million US$ and is forecast to xx million US in 2025, growing at a CAGR of xx% from 2018. (researchmoz.us)
  • To study and analyze the global Potassium Channel Blocker market size (value & volume) by company, key regions/countries, products and application, history data from 2013 to 2017, and forecast to 2025. (researchmoz.us)
  • (19,20) ShK-186, now called Dalazatide, was advanced to human trials in 2015-2017 by Shawn Iadonato and Eric Tarcha at KPI Therapeutics, Seattle, USA, as the first-in-man K v 1.3 blocker for autoimmune disease. (wikiversity.org)
  • Based on the structural similarity between hBD1 and Kv1.3 channel-sensitive hBD2, hBD1 was found to selectively inhibit human and mouse Kv1.3 channels with IC50 values of 11.8 ± 3.1 μM and 13.2 ± 4.0 μM, respectively. (usda.gov)
  • Different from hBD2 modifying Kv1.3 channel activation and increasing activation time constant, hBD1 did not affect the activation feature of both human and mouse Kv1.3 channels. (usda.gov)
  • Together, these findings enhance knowledge of hBD1 as a new immune-related Kv1.3 channel blocker and highlight the major functional differences between hBD1 and hBD2 to explore in future research. (usda.gov)
  • Charybdotoxin (CTX) * and margatoxin (MgTX), which block the predominant voltage-dependent potassium (Kv) channel (Kv1.3) of peripheral lymphocytes, depolarize the plasma membrane ( 3 - 5 ), and thereby inhibit TCR-mediated calcium influx ( 6 - 8 ), IL-2 production ( 9 ), and proliferation ( 9 , 10 ). (rupress.org)
  • Using a combination of biochemistry, electrophysiology, and imaging techniques, we now show that NMDARs have a key role in mediating the effect of leptin to modulate -cell electrical activity by promoting AMP-activated protein kinase (AMPK)-dependent trafficking of K and Kv2.1 channels to the plasma membrane. (bireme.br)
  • Conversely, activation of NMDARs mimicked the effect of leptin, causing Ca influx, AMPK activation, and increased trafficking of K and Kv2.1 channels to the plasma membrane, and triggered membrane hyperpolarization. (bireme.br)
  • These open plasma membrane ATP-sensitive potassium channels. (flashcardmachine.com)
  • Calcium signals are initiated in immune cells by the process of store-operated calcium entry (SOCE), where receptor activation triggers transient calcium release from the endoplasmic reticulum, followed by opening of plasma-membrane calcium-release activated calcium (CRAC) channels. (pnas.org)
  • Marie-France Martin-Eauclaire and Pierre E. Bougis, "Potassium Channels Blockers from the Venom of Androctonus mauretanicus mauretanicus ," Journal of Toxicology , vol. 2012, Article ID 103608, 9 pages, 2012. (hindawi.com)
  • The effect of the volume-activated Cl- channel inhibitor tamoxifen was to eliminate this difference in the times of onset of RVD in coupled cell pairs and to inhibit RVD in both the NPCE and PCE cells partially. (biomedsearch.com)
  • There is no cure for LEMS, as scientists have not yet figured out how to selectively stop the autoimmune attack on motor nerve terminal calcium channels and other nerve terminal proteins targeted by LEMS. (mda.org)
  • A scientific study conducted at the Dr. Rath Research Institute shows that commonly used prescription medications classified as channel blockers (widely used for management of high blood pressure, arrhythmias, angina pectoris and other conditions) can lead to deprivation of vitamin C inside the cells. (dr-rath-foundation.org)
  • Analeptics can act as potassium channel blockers , ampakines , and serotonin receptor agonists , and adenosine antagonism. (wikipedia.org)
  • In addition, such a database shall be a useful tool to conduct further studies on the channels themselves, which are today considered as pharmacological targets for certain autoimmune, oncological and neurodegenerative diseases. (ibch.ru)
  • NMDA receptors mediate leptin signaling and regulate potassium channel trafficking in pancreatic -cells. (bireme.br)
  • We find that SK channels regulate the firing of both young and adult Purkinje neurons and that somatic and dendritic SK channels play somewhat different roles in this regulation. (jneurosci.org)
  • New concepts on potassium channel function in neuroinflammation suggest that they regulate mechanisms of microglial activation, including intracellular calcium homeostasis, morphological alterations, pro-inflammatory cytokine release, antigen presentation, and phagocytosis. (frontiersin.org)
  • Kv channels also regulate the loss of intracellular K + , which is a prerequisite step in normotonic or FAS-mediated apoptosis ( 11 - 13 ) and regulatory volume responses to hypotonic (low osmolarity) stress ( 6 ). (rupress.org)
  • In naive lymphocytes, Kv channels regulate the activation of β-integrins ( 14 ), which participate in cellular adhesion and transmigration through the endothelium of venules. (rupress.org)
  • We suggest that the less structured minor conformer increases the exposure of Y23, known to contribute to binding affinity and selectivity, thereby facilitating its interaction with potassium channels. (nih.gov)
  • Lead optimization with medicinal chemistry generated ML418, which exhibits sub-micromolar activity (IC 50 = 310 nM) and superior selectivity over other Kir channels (at least 17-fold selective over Kir1.1, Kir2.1, Kir2.2, Kir2.3, Kir3.1/3.2, and Kir4.1) except for Kir6.2/SUR1 (equally potent). (nebraska.edu)