title: Release of acetylcholine from tissue slices of the rat nucleus basalis magnocellularis.
abstract: We investigated the release of acetylcholine (ACh) from tissue slices obtained from the nucleus basalis magnocellularis (nbM) of the rat brain. Potassium (35 mM) depolarization produced a 10- to 12-fold increase in the release of endogenous ACh above spontaneous release. Potassium-evoked ACh release was Ca2+ dependent. Injection of the excitotoxin quinolinic acid into the nbM produced a 72.8 +/- 13.0% decrease in spontaneous ACh release and a 60.4 +/- 8.2% decrease in potassium-evoked release. A fourfold increase in ACh release was observed following perfusion of the tissue with 1 mM 3,4-diaminopyridine (3,4-DAP) whereas 10 mM 3,4-DAP caused a sevenfold increase. The increase in ACh release caused by 3,4-DAP was inhibited by tetrodotoxin. Tissue slices accumulated [3H]choline by high-affinity choline uptake and this could be inhibited by hemicholinium-3. These results indicate that ACh can be released from tissue slices of the nbM by a calcium-dependent process and that a part of this release appears to be from the cholinergic neurons of the nbM.
authors.affiliation: Department of Pharmacology and Toxicology, Queen's University, Kingston, Ontario, Canada.
authors.forename: R H
authors.initials: RH
authors.lastname: Metcalf
authors.forename: R J
authors.initials: RJ
authors.lastname: Boegman
mesh_terms: D015761:4-Aminopyridine / Q000031:analogs & derivatives*; D000109:Acetylcholine / Q000378:metabolism*; D000077770:Amifampridine; D000631:Aminopyridines / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D011188:Potassium / Q000494:pharmacology; D017378:Quinolinic Acid; D011805:Quinolinic Acids / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013116:Spinal Cord / Q000201:enzymology / Q000378:metabolism*
chemical_list: D000631:Aminopyridines; D011805:Quinolinic Acids; D015761:4-Aminopyridine; D002795:Choline O-Acetyltransferase; D017378:Quinolinic Acid; D000109:Acetylcholine; D000077770:Amifampridine; D011188:Potassium; D002118:Calcium