Female sexual behavior following intracerebral infusion of the 5-HT1A agonist, 8-OH-DPAT, into the medial preoptic area.

The effects of intracerebral infusions of the 5-HT1A agonist, 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), on sexual behaviors of intact, proestrous rats were examined. When administered into either the rostral or the caudal portions of the medial preoptic area (mPOA), bilateral infusions of 200, 500, or 2,000 ng of 8-OH-DPAT reduced lordosis behavior (e.g. the lordosis/mount ratio; L/M) and increased the female's resistance to the male's attempts to mount. Infusions within the mid-rostrocaudal mPOA failed to suppress lordosis behavior but were as effective as the rostral or caudal infusions in the elicitation of resistive behavior. A reduction in the L/M ratio was usually accompanied by a slight decline in the quality of the lordosis reflex; proceptivity, as evidenced by the occurrence of hopping and darting behavior, was not consistently reduced by 8-OH-DPAT. In fact, 4 out of 7 rats that received mid-rostrocaudal infusions of 8-OH-DPAT showed a "frenzied" accentuation of hopping and darting behavior. These results suggest that 5-HT1A receptors in the mPOA play an important role in several components of female sexual behavior. The identification of a rostral and caudal location of mPOA sites where 8-OH-DPAT suppressed lordosis behavior is consistent with the organization of 5-HT fibers in the mPOA and with ventromedial hypothalamic (VMN) input into the mPOA.