Article date: 1985/7/22
PubMed ID: 2992695
Journal name: Brain research (ISSN: 0006-8993)
Modulation of binding of [3H]muscimol, a GABAA receptor agonist, by natural and synthetic glucocorticoids was investigated in crude synaptosomal membranes and in brain sections of rat. In adrenalectomized (Adx) rats, muscimol binding was reduced by 30-50% in cerebral cortex, cerebellum, thalamus and hippocampus, as compared to sham-operated controls. This decrease was due to reduced binding affinities of GABA receptors for muscimol. In contrast muscimol binding was increased by 38% in the hypothalamus and did not change in the pons-medulla after Adx. Nanomolar concentrations of corticosterone and pregnenolone-sulfate, but not dexamethasone, enhanced muscimol binding in brain regions that were characterized by reduced binding following Adx. This steroid-induced increase in muscimol binding was due to enhanced affinities of GABA receptors.
Author List: Majewska M D, Bisserbe J C, Eskay R L
Publication Types: Comparative Study; Journal Article
Substances mentioned in the article: Glucocorticoids; Receptors, GABA-A; pregnenolone sulfate; Muscimol; Pregnenolone; Dexamethasone; Corticosterone;
Mesh terms: Adrenalectomy; Animals; Brain/physiology; Corticosterone/pharmacology; Dexamethasone/pharmacology; Glucocorticoids/physiology; Muscimol/metabolism; Pregnenolone/pharmacology; Rats; Rats, Inbred Strains; Receptors, GABA-A/drug effects;