Muscarinic suppression of a novel voltage-sensitive K+ current in a vertebrate neurone.
Cholinergic excitation of vertebrate neurones is frequently mediated through the action of acetylcholine on muscarinic (atropine-sensitve) receptors. This type of excitation differs substantially from the better known nicotinic excitation. One difference is that, instead of an increased membrane conductance, a decreased conductance (to K+ ions) frequently accompanies muscarinic depolarisation. This has been detected in sympathetic, cortical and hippocampal neurones. Using voltage-clamped frog sympathetic neurones we have now identified a distinctive voltage-sensitive K+-current, separate from the delayed rectifier current, as the prime target for muscarinic agonists. We have termed this current the M-current, IM.
D000818:Animals; D001001:Anura; D004553:Electric Conductivity; D005728:Ganglia, Sympathetic / Q000502:physiology*; D066298:In Vitro Techniques; D009116:Muscarine / Q000494:pharmacology; D009474:Neurons / Q000502:physiology; D011188:Potassium / Q000502:physiology*; D011892:Rana catesbeiana; D011950:Receptors, Cholinergic / Q000502:physiology*; D011976:Receptors, Muscarinic / Q000187:drug effects / Q000502:physiology*; D013757:Tetraethylammonium Compounds / Q000494:pharmacology
D011950:Receptors, Cholinergic; D011976:Receptors, Muscarinic; D013757:Tetraethylammonium Compounds; D009116:Muscarine; D011188:Potassium