Evidence for GABAB autoreceptors in median eminence.
The effect of the selective GABAB receptor agonist baclofen was examined on stimulus-induced release of [3H]GABA from crude synaptosomal preparations of median eminence (ME) and pituitary neurointermediate lobe (NI). Baclofen stereospecifically inhibited release of [3H]GABA in a concentration-dependent manner from ME but had no effect in NI. The effect of (+/-) baclofen was partly antagonized by the putative GABAB receptor antagonist delta-aminovaleric acid, but these experiments were complicated by a degree of heteroexchange. These results provide the first evidence for GABAB autoreceptors in the CNS.
D000818:Animals; D001418:Baclofen / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D008473:Median Eminence / Q000378:metabolism*; D009411:Nerve Endings / Q000378:metabolism; D010902:Pituitary Gland / Q000378:metabolism; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011963:Receptors, GABA-A / Q000378:metabolism*; D013237:Stereoisomerism
D011963:Receptors, GABA-A; D001418:Baclofen; D011188:Potassium