Muscarinic suppression of a novel voltage-sensitive K+ current in a vertebrate neurone

Nature. 1980 Feb 14;283(5748):673-6. doi: 10.1038/283673a0.


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.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Anura
  • Electric Conductivity
  • Ganglia, Sympathetic / physiology*
  • In Vitro Techniques
  • Muscarine / pharmacology
  • Neurons / physiology
  • Potassium / physiology*
  • Rana catesbeiana
  • Receptors, Cholinergic / physiology*
  • Receptors, Muscarinic / drug effects
  • Receptors, Muscarinic / physiology*
  • Tetraethylammonium Compounds / pharmacology


  • Receptors, Cholinergic
  • Receptors, Muscarinic
  • Tetraethylammonium Compounds
  • Muscarine
  • Potassium