title: The pharmacology of quisqualate and AMPA in the cerebral cortex of the rat in vitro.
abstract: The depolarising population response to the excitatory amino acids, quisqualate and AMPA, in slices of cerebral cortex of the rat have been compared. Their respective dose-response curves had a similar maximum but the slope of the curve for AMPA was consistently steeper than that for quisqualate. The dose-response curves for AMPA had a mean log EC50 of -5.18 +/- 0.05, which was significantly different from -4.62 +/- 0.07 the mean log EC50 of the dose-response curves for quisqualate. Responses to both agonists were antagonised by kynurenic acid, barbiturates and gamma-DGT to a similar extent. The antagonism by kynurenate appeared to be competitive whilst the barbiturates were evidently noncompetitive antagonists. These results are in agreement with claims that quisqualate and AMPA act at a similar recognition site. The differences in the slopes of the dose-response curves for quisqualate and AMPA may be explained by the differences in the cellular uptake of the two agonists and/or by differences in efficacy.
authors.affiliation: Department of Pharmacology, School of Pharmacy, London, U.K.
authors.forename: A L
authors.initials: AL
authors.lastname: Horne
authors.forename: M A
authors.initials: MA
authors.lastname: Simmonds
mesh_terms: D000818:Animals; D002540:Cerebral Cortex / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D005973:Glutamine / Q000494:pharmacology / Q000031:analogs & derivatives; D007051:Ibotenic Acid / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D066298:In Vitro Techniques; D007736:Kynurenic Acid / Q000494:pharmacology; D008297:Male; D009467:Neuromuscular Depolarizing Agents / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D010069:Oxadiazoles / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D010080:Oxazoles / Q000494:pharmacology*; D010424:Pentobarbital / Q000494:pharmacology; D016318:Quisqualic Acid; D051381:Rats; D011919:Rats, Inbred Strains; D013654:Taurine / Q000494:pharmacology / Q000031:analogs & derivatives; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid
chemical_list: D009467:Neuromuscular Depolarizing Agents; D010069:Oxadiazoles; D010080:Oxazoles; D005973:Glutamine; D013654:Taurine; D007051:Ibotenic Acid; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; D016318:Quisqualic Acid; C020903:glutaurine; D007736:Kynurenic Acid; D010424:Pentobarbital