title: Muscarinic receptors mediate attenuation of extracellular acetylcholine levels in rat cerebral cortex after cholinesterase inhibition.
abstract: 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.
authors.affiliation: Department of Pharmacology, Southern Illinois University School of Medicine, Springfield 62794-9230.
authors.forename: E
authors.initials: E
authors.lastname: Messamore
authors.forename: U
authors.initials: U
authors.lastname: Warpman
authors.forename: E
authors.initials: E
authors.lastname: Williams
authors.forename: E
authors.initials: E
authors.lastname: Giacobini
mesh_terms: D000109:Acetylcholine / Q000378:metabolism*; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002540:Cerebral Cortex / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D002800:Cholinesterase Inhibitors / Q000494:pharmacology*; D003956:Dialysis; D005110:Extracellular Space / Q000187:drug effects / Q000378:metabolism; D008297:Male; D010830:Physostigmine / Q000031:analogs & derivatives / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011976:Receptors, Muscarinic / Q000187:drug effects / Q000502:physiology*
chemical_list: D002800:Cholinesterase Inhibitors; D011976:Receptors, Muscarinic; C052450:physostigmine heptyl; D001285:Atropine; D010830:Physostigmine; D000109:Acetylcholine