Sexual experience confers resilience to restraint stress in female rats

During paced mating, sexually experienced female rats spend more time with the male, return to the male more quickly after intromission, and exhibit shorter interintromission intervals as compared to sexually naïve rats. Factors that trigger the shift in paced mating behavior are unknown. The present study used the elevated plus maze to test whether anxiety-like behavior differs as a function of sexual experience. Ovariectomized, Long-Evans female rats were primed with estradiol benzoate plus progesterone (EB + P) and then either received four, twice weekly, paced mating treatments to gain sexual experience (Experienced) or remained sexually naïve (Naïve) but were exposed to an empty mating apparatus. In Experiment 1, anxiety-like behavior was compared between Experienced or Naïve female rats that were primed with either EB + P or oil. Significantly more time was spent in open arms under EB + P vs. oil, independent of sexual history. To test whether exposure to an acute stressor before elevated plus maze testing affected anxiety-like behavior, EB + P treated, Experienced or Naïve rats received paced mating (Experiment 2) or restraint (Experiment 3) immediately prior to the elevated plus maze task. Restraint, but not mating, led to less anxiety-like behaviors for Experienced rats compared to Naïve rats. Collectively, our data shows that one component of the shift in paced mating behavior that occurs with sexual experience appears to be altered stress responsiveness. We propose that mating is a beneficial stressor that, when repeated, increases the ability to cope with anxiety-producing events such as aversive components of mating or non-voluntary stressors.