title: Pirmenol inhibits muscarinic acetylcholine receptor-operated K+ current in the guinea pig heart.
abstract: We examined the effects of pirmenol and disopyramide on the muscarinic acetylcholine receptor-operated K+ current (I[K.ACh]) in atrial cells and on experimental atrial fibrillation in isolated guinea-pig hearts. In isolated atrial myocytes, both pirmenol and disopyramide concentration-dependently inhibited the I(K.ACh) induced by carbachol or intracellular loading of GTPgammaS. Their inhibitory effects on the carbachol-induced current were more potent than those on GTPgammaS-induced current, suggesting that these drugs inhibit I(K.ACh) mainly by blocking muscarinic receptors. In Langendorff-perfused hearts these drugs reversed the carbachol-induced decreases in effective refractory periods and atrial fibrillation threshold. These drugs may be useful for the prevention of vagally induced atrial fibrillation.
authors.affiliation: Department of Pharmacology, School of Medicine, Chiba University, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Y
authors.initials: Y
authors.lastname: Hara
authors.forename: M
authors.initials: M
authors.lastname: Tamagawa
authors.forename: H
authors.initials: H
authors.lastname: Nakaya
mesh_terms: D000200:Action Potentials; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology*; D001281:Atrial Fibrillation / Q000188:drug therapy; D002217:Carbachol / Q000037:antagonists & inhibitors; D004206:Disopyramide / Q000494:pharmacology*; D004558:Electric Stimulation; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects* / Q000502:physiology; D018408:Patch-Clamp Techniques; D010880:Piperidines / Q000494:pharmacology*; D015221:Potassium Channels / Q000187:drug effects; D011976:Receptors, Muscarinic / Q000187:drug effects*
chemical_list: D000889:Anti-Arrhythmia Agents; D010880:Piperidines; D015221:Potassium Channels; D011976:Receptors, Muscarinic; D002217:Carbachol; D004206:Disopyramide; C024318:pirmenol