Muscarinic modulation of a transient K+ conductance in rat neostriatal neurons

Paul T. Akins, D. James Surmeier*, S. T. Kitai

*Corresponding author for this work

Research output: Contribution to journalArticle

121 Scopus citations

Abstract

Neurons of the neostriatum are richly innervated by cholinergic neurons of intrinsic origin1-3. Both pre- and post-synaptic muscarinic receptors mediate the effects of acetylcholine (ACh) 4-6. Activation of these receptors is functionally significant, particularly in Parkinson's disease7. Current-clamp studies indicate that muscarinic receptors serve to decrease the responsiveness of neostriatal neurons to excitatory inputs8-10. Here we present evidence that this effect is caused, in part, by the muscarinic modulation of the A-current, a transient outward potassium current. The voltage dependence of this current suggets that normally it enhances spike repolarization and slows discharge rate, but does not affect 'synaptic integration'. We find that under the influence of muscarinic agonists, the voltage dependence of A-current activation and inactivation is shifted towards more negative membrane potentials and the peak conductance is increased. Therefore, at relatively hyperpolarized resting potentials, ACh transiently alters the functional role of the A-current, allowing it to suppress excitatory inputs and further slow the discharge rate. But at relatively depolarized resting potentials, ACh increases excitability by removing the A-current through inactivation.

Original languageEnglish (US)
Pages (from-to)240-242
Number of pages3
JournalNature
Volume344
Issue number6263
DOIs
StatePublished - 1990

ASJC Scopus subject areas

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