Context alters the ability of clitoral stimulation to induce a sexually-conditioned partner preference in the rat

We have shown previously that clitoral stimulation (CLS) of female rats induces significant conditioned place preference (CPP), indicating that it is rewarding. The present study asked whether CLS could induce a conditioned partner preference. In the first experiment, sexually naïve females received 10 alternating trials of CLS and No-CLS in the presence of a male rat behind a wire-mesh screen. For one group, CLS was made in the presence of the male scented with almond extract. On alternating trials, those females received sham CLS in the presence of an unscented male behind the screen. The order was reversed for the other group. After 5 trials in each condition, females were placed into an open field with two sexually vigorous males, one scented and the other unscented. Contrary to expectation, females displayed a preference for the male associated with sham CLS. The second experiment examined whether a partner preference could be conditioned by associating CLS with the almond odor alone. A new group of sexually naive females received the same CLS-odor, No-CLS-No Odor pairings as above, but with the odor presented on cotton gauze in the chamber. During the final open field test, those females selectively solicited the scented male. We conclude that CLS that induces CPP also induces conditioned partner preference. However, we propose that CLS in the presence of an inaccessible male created a sexual inhibitory state for female rats.

Research highlights
► Sexually naïve female rats given rewarding clitoral stimulation in the presence of a neutral almond odor display a conditioned preference to approach and solicit sexual interaction selectively from almond-scented males during their first sexual experience.
► However, sexually naïve female rats given experience with clitoral stimulation in the presence of an inaccessible scented male chose unscented males to approach and solicit sexual interaction with during their first sexual experience. Those females attempted unsuccessfully to solicit the scented male during conditioning trials, and may therefore have experienced a state of sexual frustration that was associated with the odor.
► Context thus appears to determine the reward value of clitoral stimulation. Clitoral stimulation is rewarding in its own right, and stimulates a partner preference. However, in the presence of a male rat, clitoral stimulation facilitates approach and solicitation behaviors toward the male. When such approach and solicitation is thwarted because the male is inaccessible, the state of sexual frustration is associated with the odor and drives females to choose unscented males.