Endogenous gamma-aminobutyric acid tonically inhibits release of alpha-melanocyte-stimulating hormone from rat hypothalamic slices.
Release of immunoreactive alpha-melanocyte-stimulating hormone (alpha-MSH) from superfused slices of rat hypothalamus was stimulated by the gamma-aminobutyric acid (GABA) receptor antagonist, bicuculline, and inhibited by the benzodiasepine, chlordiazepoxide, an allosteric GABA receptor modulator, demonstrating the presence of tonic inhibition of alpha-MSH release by endogenous GABA in hypothalamic tissue. Chlordiazepoxide increased the effect of exogenous GABA which by inhibiting basal release of alpha-MSH demonstrated that the tonic inhibition was not maximal in the resting state.
Mabley
J
J
Department of Pharmacology and Therapeutics, University of Wales College of Medicine, Cardiff U.K.
Wayman
C P
CP
Wilson
J F
JF
D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D058787:GABA-A Receptor Antagonists; D007031:Hypothalamus / Q000033:anatomy & histology / Q000378:metabolism* / Q000648:ultrastructure; D011724:Pyridazines / Q000494:pharmacology; D051381:Rats; D011963:Receptors, GABA-A / Q000502:physiology; D000521:alpha-MSH / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology / Q000502:physiology*
D058787:GABA-A Receptor Antagonists; D011724:Pyridazines; D011963:Receptors, GABA-A; D005680:gamma-Aminobutyric Acid; D000521:alpha-MSH; C049853:gabazine; D001640:Bicuculline