Muscarinic receptors mediate attenuation of extracellular acetylcholine levels in rat cerebral cortex after cholinesterase inhibition

Neurosci Lett. 1993 Aug 20;158(2):205-8. doi: 10.1016/0304-3940(93)90265-m.


Muscarinic autoregulation of extracellular acetylcholine levels was investigated by microdialysis in the cerebral cortex of freely moving rats under basal conditions as well as following systemic administration of a reversible cholinesterase inhibitor. Atropine (2.2 mg/kg s.c. or 0.2 microM via the dialysis probe) did not affect basal extracellular acetylcholine levels in the cerebral cortex. However, it did potentiate the elevation of extracellular acetylcholine levels produced by a dose of systemic heptylphysostigmine which inhibited 25% of cortical and 40% of plasma cholinesterase activity. These observations suggest that the extracellular concentration of acetylcholine following moderate acetylcholinesterase inhibition is regulated through muscarinic receptors.

Publication types

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

MeSH terms

  • Acetylcholine / metabolism*
  • Animals
  • Atropine / pharmacology
  • Cerebral Cortex / drug effects
  • Cerebral Cortex / enzymology
  • Cerebral Cortex / metabolism*
  • Cholinesterase Inhibitors / pharmacology*
  • Dialysis
  • Extracellular Space / drug effects
  • Extracellular Space / metabolism
  • Male
  • Physostigmine / analogs & derivatives
  • Physostigmine / pharmacology
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Muscarinic / drug effects
  • Receptors, Muscarinic / physiology*


  • Cholinesterase Inhibitors
  • Receptors, Muscarinic
  • physostigmine heptyl
  • Atropine
  • Physostigmine
  • Acetylcholine