Effects of the cannabinoid antagonist SR 141716 on sexual and motor behaviour in receptive female rats

The aim of the present study was to investigate the effect of the cannabinoid antagonist/inverse agonist SR 141716 (SR) on the receptive behaviour and sexual motivation of female rats. Partner preference, receptivity and proceptivity were evaluated in ovariectomized female rats primed with oestrogen and progesterone and administered SR (1 or 2.5 mg/kg, i.p.) 20 min prior to testing. In the partner preference test, a reduced interest in both stimulus animals (a sexually active male and an ovariectomized hormone-primed female) was detected in rats treated with SR at both doses, but no effect on preference score was observed. In the receptivity test, pronounced reductions in lordosis quotient, lordosis rating and in the percentage of receptive females were found in SR-treated rats compared with control rats. Proceptive behaviours were not significantly affected by either dose of SR. In addition, we explored the behavioural effects induced by SR in female rats using the open field test. Only at the higher dose (i.e. 2.5 mg/kg) did SR markedly increased grooming and scratching behaviour. The results demonstrate the ability of SR to reduce female sexual receptivity, but not sexual motivation. The reduction does not seem strictly related to the motor alterations induced by the cannabinoid antagonist.