IMBECU   20882
INSTITUTO DE MEDICINA Y BIOLOGIA EXPERIMENTAL DE CUYO
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Effect of allopregnanolone on the GnRH secretion from the hypothalamus of pubertal female rats
Autor/es:
GIULIANI, FERNANDO A; DI GIORGIO, NOELIA P; YUNES, ROBERTO; LUX LANTOS, VICTORIA AR; CABRERA, RICARDO
Lugar:
Dourado - Sao Paulo
Reunión:
Workshop; 2013 International Workshop in Neuroendocrinology; 2013
Institución organizadora:
International
Resumen:
Introduction: The early activation of the GnRH neural network at puberty is influenced by glutamatergic and GABAergic inputs whose activity may be regulated by factors such as the GABAA receptor modulator allopregnanolone (Allo). Previously we reported that the expression of the enzyme that synthesizes Allo increases in the hypothalamus as the rat develops from prepubertal to pubertal stage. Also, we demonstrated that Allo in vitro modulates the hypothalamic K+-evoked glutamate and GABA release through mechanisms mediated by GABAA and NMDA receptors and reduces the spontaneous release of GABA. We hypothesize that Allo is also able to regulate the pubertal GnRH release through the modulation of neurotransmitters receptors in a way that could correlate with our previous results. Objetives: (1) To determine the in vitro effect of Allo on the GnRH secretion from the hypothalamus of prepubertal (PP), vaginal opening (VO) and pubertal (P) rats; and (2) to determine the possible modulatory effect of Allo on GABAA and NMDA receptors. Methods: (1) Slices of mediobasal hypothalamus (MBH) and anterior preoptic areas (APOA) dissected from PP, VO and P rats were incubated for 30 min in 120 nM Allo after a 30 min pre-incubation with vehicle. (2) HMB-APOA slices from P rats were incubated for 30 min in 120 nM Allo supplemented with the GABAA receptor antagonist bicuculline (9.8 µM), the NMDA receptor antagonist AP-7 (100 µM) or the NMDA blocker Mg2+ (1.2 mM) after a 30 min pre-incubation with solutions of the antagonists alone. The supernatants of the experiments (1) and (2) were then used in a radioimmunoassay to measure the secreted GnRH. The results were compared by 2-way and 1-way ANOVA respectively and Bonferroni post tests (p