GABAergic drugs and sexual behaviour in the male rat

The GABAA agonists 3-amino-1-propanesulfonic acid and THIP reduced sexual behaviour in male rats only at relatively high doses, whereas baclofen produced an almost complete inhibition at a low dose (2.5 mg/kg). The GABA transaminase inhibitor aminooxyacetic acid had no effects, while gamma-acetylenic GABA produced a slight inhibition of sexual behaviour. The GABAA antagonist bicuculline had no effect. When THIP was administered concurrently with bicuculline, the former drug was potentiated. Therefore it is concluded that the GABAA receptor is not responsible for the inhibitory actions of THIP, and since baclofen was the most potent drug with regard to effects on sexual behaviour, it is suggested that the GABAB rather than the GABAA receptor is involved in the control of that behaviour. The slight effects of the transaminase inhibitors and the lack of effect of bicuculline suggest that the GABAergic neurons participating in the control of sexual activity are not tonically active. Finally, data are presented showing that the effects of GABAergic drugs on sexual behaviour are probably independent from those on locomotor activity.