title: A new quisqualate receptor subtype (sAA(2)) responsible for the glutamate-induced inositol phosphate formation in rat brain synaptoneurosomes.
abstract: Inositol phosphate synthesis elicited by excitatory amino acids was measured in rat forebrain synaptoneurosomes in presence of Li(+). Quisqualate (QA) was the most potent excitatory amino acid inducing inositol phosphate formation. This QA action was not blocked by any of the usual antagonists [glutamate-amino-methyl-sulphonate (GAMS); glutamate-diethyl-ester (GDEE); ?-d-glutamyl-glycine (?-DGG)] known to inhibit the QA-induced depolarization. The same was found for the most potent and selective QA antagonist reported so far [6-nitro-7-cyanoquinoxaline-2,3-dion (FG 9065)]. In addition, dl-?-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) a potent depolarizing agonist at the quisqualate receptor subtype was about 300 times less potent than quisqualate in increasing inositol phosphate accumulation. Our results provide the first pharmacological evidence indicating that a new quisqualate receptor subtype, tentatively termed sAA(2) is responsible for inositol phosphate formation.
authors.affiliation: Centre CNRS-INSERM de Pharmacologie-Endocrinologie, Rue de la Cardonille, 34094 Montpellier Cedex, France.
authors.forename: M
authors.initials: M
authors.lastname: Recasens
authors.forename: J
authors.initials: J
authors.lastname: Guiramand
authors.forename: A
authors.initials: A
authors.lastname: Nourigat
authors.forename: I
authors.initials: I
authors.lastname: Sassetti
authors.forename: G
authors.initials: G
authors.lastname: Devilliers