Sex differences in GABA-mediated calcium influx in hypothalamic neurons

MIR, F.; WILSON, C.; CAMBIASSO, M.J.

cordoba

Congreso; XXXIII Reunión Anual de la Sociedad Argentina de Investigación en Neurociencias (SAN); 2018

Sociedad Argentina de Investigación en Neurociencias (SAN)

GABAA receptor (GABAAR) activation exerts trophicactions in immature neurons through depolarization of restingmembrane potential gating the opening of voltage-dependentcalcium channels. Previous results from our lab haveshown gender-biased GABAAR responses in cultured hypothalamicneurons. These differences were found beforebrain masculinization by gonadal hormones. Consideringthese, in this work we evaluated the GABAAR-mediatedCa2þentry in cultured neurons segregated by gonadaltype. Hypothalamic cells were obtained from embryonicbrains at E16 (both male and female), 2 days before thepeak of testosterone production by the fetal testis, and culturedfor 2 days. To measure calcium signals, neurons wereloaded with the calcium indicator Cal-520, followed by atime-lapse recording on live cells using a spinning disk microscope.Our results show that there are more male thanfemale neurons responding to GABAAR stimulation.Additionally, almost 50% of male neurons did not recoverbasal calcium level after stimulation, in contrast to only 20%observed in females. Moreover, although nifedipine blocksintracellular calcium entry equally, it was stronger in males.Together, these results highlight the influence of neural sexdifferences irrespectively of sexual hormone exposure.