title: GABA(B) receptors in neuroendocrine regulation.
abstract: Gamma-amino butyric acid (GABA), in addition to being a metabolic intermediate and the main inhibitory neurotransmitter in the synaptic cleft, is postulated as a neurohormone, a paracrine signaling molecule, and a trophic factor. It acts through pre- and post-synaptic receptors, named GABA(A) and GABA(C) (ionotropic receptors) and GABA(B) (metabotropic receptor). Here we reviewed the participation of GABA(B) receptors in the regulation of the hypothalamic-pituitary-gonadal axis, using physiological, biochemical, and pharmacological approaches in rats, as well as in GABA(B1) knock-out mice, that lack functional GABA(B) receptors. Our general conclusion indicates that GABA(B )receptors participate in the regulation of pituitary hormone secretion acting both in the central nervous system and directly on the gland. PRL and gonadotropin axes are affected by GABA(B) receptor activation, as demonstrated in the rat and also in the GABA(B1) knock-out mouse. In addition, hypothalamic and pituitary GABA(B) receptor expression is modulated by steroid hormones. GABA participation in the brain control of pituitary secretion through GABA(B) receptors depends on physiological conditions, being age and sex critical factors.These results indicate that patients receiving GABA(B) agonists/antagonists should be monitored for possible endocrine side effects.
authors.affiliation: Laboratory of Neuroendocrinology, Instituto de Biología y Medicina Experimental-CONICET, V. de Obligado 2490, C1428ADN, Buenos Aires, Argentina.
authors.forename: Victoria A
authors.initials: VA
authors.lastname: Lux-Lantos
authors.forename: María S
authors.initials: MS
authors.lastname: Bianchi
authors.forename: Paolo N
authors.initials: PN
authors.lastname: Catalano
authors.forename: Carlos
authors.initials: C
authors.lastname: Libertun
mesh_terms: D000818:Animals; D001921:Brain / Q000502:physiology; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology; D051379:Mice; D018345:Mice, Knockout; D009490:Neurosecretory Systems / Q000502:physiology*; D010907:Pituitary Hormones / Q000378:metabolism; D010913:Pituitary-Adrenal System / Q000502:physiology; D051381:Rats; D018080:Receptors, GABA-B / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*
chemical_list: D010907:Pituitary Hormones; D018080:Receptors, GABA-B