[Effect of muscimol (GABA-agonist) on thalamo-hypothalamic regulation by corticotropic efferents (thalamic model)].

Article date: 1985/1/1

PubMed ID: 2935233

Journal name: Comptes rendus des seances de la Societe de biologie et de ses filiales (ISSN: 0037-9026)


It can be assumed from previous data that the stress-induced polyphasic adrenocortical response involves two phenomenons. First, direct hypothalamic afferents stimulate the adrenocorticotropic axis resulting in a rapid increase in plasma corticosterone levels up to a maximum of about 40 ng . ml-1 at 15 min. Then, a thalamic-hypothalamic loop generates the late rebounding components. Intravenous injection of muscimol (0.5 ml . kg-1) produces only slight and short duration (45 min) disturbances (piloerection; panting; corticosteronemia). Stress application, 1 hr after muscimol administration, elicits only the first peak of corticosterone with magnitude and delay similar to that in control. However, the late rebounding component is no more visible. Thus, GABA-ergic stimulation leads to a situation similar to that seen after section of neural connections between thalamic nuclei and infundibular complex. The hypothalamic-adrenocorticotropic reactivity itself is not affected whereas the function of the regulating thalamo-hypothalamic loop is markedly impaired.

Author List: Ramade F, Baylé J D

Publication Types: Comparative Study; English Abstract; Journal Article

Substances mentioned in the article: Muscimol; Corticosterone;

Mesh terms: Animals; Columbidae; Corticosterone/secretion; Efferent Pathways/drug effects; Hypothalamus/drug effects; Muscimol/pharmacology; Stress, Physiological/physiopathology; Thalamus/drug effects;

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