Sexual behavior regulated (paced) by the female induces conditioned place preference

The possibility that female-paced coital behavior induces a reward state of sufficient intensity and duration to induce conditioning was evaluated by the conditioned-place-preference paradigm. Ovariectomized female rats, treated with estradiol benzoate and progesterone, regulated (paced) their coital interactions with a stud male through a 2-compartment chamber in which only the female could freely move from one compartment to the other. The females that paced their coital interactions showed a clear place preference. In contrast, no change in preference was observed in the females that could not pace their coital contacts. The change in preference in the females that paced their coital interactions was similar to that produced by an injection of morphine (1 mg/kg). These results suggest that coital interactions in females can induce a reward state when the females can control the pace of the sexual interaction.