Differential regulation of female sexual behaviour by dopamine agonists in the medial preoptic area

Abstract

The medial preoptic area (mPOA) is a brain region critical in the control of male sexual behaviour, and the neurotransmitter dopamine (DA) plays an important role within it. However, both the roles of DA and the mPOA in female sexual behaviour are not fully understood, with few studies producing consistent data. The present study examined the function of DA within the mPOA on the full cascade of female sexual behaviour. Ovariectomized female rats were bilaterally cannulated into the mPOA and partially hormonally primed with estradiol benzoate (EB). Different doses of a nonselective DA receptor agonist, and selective DA D1 and D2 receptor agonists (apomorphine, SKF 38393 and quinpirole, respectively) were infused bilaterally to the mPOA. Copulatory behaviour was then immediately tested over a period of 30 min in a bilevel chamber with a sexually experienced male. Precopulatory behaviours were increased in females following infusions of a low dose (0.25μg) of apomorphine and both a low (0.05μg) and a high dose (0.2μg) of quinpirole. However, hops and/or darts were decreased following infusion of a low dose (0.05μg) of SKF 38393. These results suggest that the ratio of DA D1/D2 activity within the mPOA of female rats is critical for the expression of precopulatory behaviours, and may work with other brain areas responsible for stimulating lordosis to control the timing of female sexual behaviour.