GABA inhibits sexual behaviour in female rats

Ejaculation by male rats caused an abrupt and marked increase in the concentration of GABA in the cerebrospinal fluid and an equally abrupt and marked inhibition of sexual behaviour in female rats. The increase in the concentration of GABA in the cerebrospinal fluid and the inhibition of the behaviour was specifically mediated by the ejaculation of the male; sexual stimulation unaccompanied by ejaculation had no effect. The post-ejaculatory suppression of sexual receptivity in female rats was partially reversed by intracerebroventricular injection of the GABA antagonist bicuculline and the behaviour of receptive rats was inhibited by intracerebroventricular injection of the GABA agonist muscimol. Increasing the concentration of GABA in the cerebrospinal fluid by i.p. injection of the GABA transminase inhibitor gamma-vinyl GABA caused an increase of the concentration of GABA in the cerebrospinal fluid and inhibited the display of sexual receptivity. It is suggested that GABA mediates physiologically relevant inhibition of sexual behaviour in female rats.