[Effects of systemic administration of muscimol (gamma-aminobutyric acid agonist) on the corticotropic adenohypophysis].

Article date: 1987/1/1

PubMed ID: 2820555

Journal name: Comptes rendus de l'Academie des sciences. Serie III, Sciences de la vie (ISSN: 0764-4469)


A short and moderate increase in plasma ACTH and corticosterone levels was observed after i.v. injection of the GABA-agonist, muscimol as a bolus of 0.5 mg . kg-1. Doses lower than 0.3 mg . kg-1 were ineffective. 6 hrs. after i.v. injection of 1 ml of an undiluted immune serum raised against oCRF41, resting hormone levels were markedly diminished, stress-induced responses were almost completely suppressed, whereas i.v. injection of muscimol still resulted in an unaltered adrenocorticotropic stimulation. Adenohypophysectomized animals displayed a low basal adrenal function, no stress-induced response and interestingly enough no longer responded to i.v. muscimol injection. Consequently, acute GABA-ergic stimulation appears to act directly onto the pituitary corticotroph cells. It cannot be inferred so far whether this action is of physiological importance but it can at least contribute to elucidate some controversial data prevailing in this field.

Author List: Ramade F, Baylé J D

Publication Types: English Abstract; Journal Article

Substances mentioned in the article: Muscimol; Adrenocorticotropic Hormone; Corticosterone;

Mesh terms: Adrenocorticotropic Hormone/blood; Animals; Columbidae; Corticosterone/blood; Hypophysectomy; Injections, Intravenous; Muscimol/administration & dosage; Pituitary Gland, Anterior/drug effects;

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