The arcuate nucleus: a site for gamma-aminobutyric acid regulation of prolactin secretion.
The effects on prolactin (Prl) secretion following microinfusion of muscimol or N-methyl-aspartate (NMA) into the medial basal hypothalamus (MBH) of male rats was determined. A highly significant increase in Prl occurred following microinfusion of muscimol (500 pmol) into the arcuate nucleus. Microinfusion of muscimol into nearby sites, such as the ventromedial nucleus and dorsal medial nucleus, was not effective in altering Prl secretion. Similarly, microinfusions of artificial cerebrospinal fluid were not effective. NMA (50 pmol), a dose found to affect hormone secretion in other CNS areas, did not alter Prl secretion when infused into the MBH. The present study was able to discriminate between CNS areas by using small volumes (250 nl) and small quantities of the amino acid agonists. This data indicates that GABAergic systems in the arcuate nucleus control Prl release from the pituitary, and that one possible mechanism is via the tuberoinfundibular dopamine system.
D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000187:drug effects / Q000502:physiology*; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D008297:Male; D009118:Muscimol / Q000494:pharmacology*; D016202:N-Methylaspartate; D011388:Prolactin / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D011963:Receptors, GABA-A / Q000187:drug effects; D005680:gamma-Aminobutyric Acid / Q000378:metabolism / Q000502:physiology*
D011963:Receptors, GABA-A; D009118:Muscimol; D001224:Aspartic Acid; D005680:gamma-Aminobutyric Acid; D016202:N-Methylaspartate; D011388:Prolactin