GABA B Receptors in Neuroendocrine Regulation

VICTORIA A. LUX-LANTOS; MARÍA S. BIANCHI; PAOLO N. CATALANO; CARLOS LIBERTUN

CELLULAR AND MOLECULAR NEUROBIOLOGY.

Springer

Año: 2007

0272-4340

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 postsynaptic receptors, named A and C (ionotropic receptors) and B (metabotropic receptor). Here we reviewed the participation of GABAB receptors in the brain regulation of pituitary secretion, using physiological, biochemical and pharmacological approaches in rats, as well as the GABAB1 knock-out mice. Our general conclusion indicates that GABAB receptors participate in the regulation of pituitary hormone secretion acting both in the central nervous system and directly at the gland.  PRL and gonadotropin axes are affected by GABAB receptor activation, as demonstrated in the rat and also in the GABAB1 knock-out mouse. In addition, hypothalamic and pituitary GABAB receptor expression is modulated by steroid hormones. GABA participation in the brain control of pituitary secretion through GABAB receptors depends on physiological conditions, being age and sex critical factors. These results indicate that patients receiving GABAB agonists/antagonists should be monitored for possible endocrine side effects.