Sexual Behavior is Enhanced by Regular, Repeated Mating from Young Adulthood to Middle Age in Female Long-Evans Rats

Abstract

The current study was designed to characterize mating behavior across age and assess the effects of age and sexual history on mating behavior. Sexual motivation was assessed using the partner-preference test, in which a female rat is given the choice to interact with a same-sex conspecific or a sexually-vigorous male rat, with which she can mate. Across repeated mating tests (2-12 months of age), female rats spent more time with the male, displayed more solicitation behaviors, were less likely to leave the male after mounts, but visited both stimulus animals less frequently. Comparing a separate group of age-matched, hormone-yoked female rats mated for the first time at 12 months of age to female rats mated for the first time at 2 months of age showed that the 12 month rats visited both stimulus animals less, were less likely to leave the male after mounts, took longer to return to the male after mounts, and displayed fewer solicitation behaviors than their younger counterparts. Relative to middle-aged female rats once they were sexually experienced, 12 month naïve rats spent less time with the male, were more likely to leave the male after mounts, and displayed fewer solicitation behaviors. Furthermore, 12 month naïve rats failed to discriminate between the stimulus animals, visiting both stimulus animals at the same rate unlike 2 month naïve or 12 month experienced rats. Taken together, these results suggest that aging affects some measures of sexual behavior, but most effects of age can be mitigated by regular, repeated mating.

Adolescence and Postpartum: Two Life Periods to Deepen Our Understanding of the Complexity of Female Rat Sexual Behavior

“…The central feature of all these tests is that the female can see, hear, and smell the stimuli but does not have physical access to them in order to evaluate the incentive value of the male without interference from the sexual experience, although allowing interaction is also used to study other aspects of female behavior [48]. These models made it possible to establish the role of the endocrine profile and previous sexual experience in the regulation of female sexual motivation (for examples, see [44,[47][48][49][50][51]).…”

“…The study of sexual behavior and motivation in the female rat has lagged in comparison to that of the male rat; however, the development of new and more complex models established female rats' active role in mating as well as the strong motivational basis of this behavior (Table 1). This review does not pretend to be exhaustive since sexual behavior in the female rat is studied in multiple models, contexts, and physiological conditions in addition to the ones mentioned above (e.g., [50,[144][145][146][147]) but rather aims to introduce two life periods that have been understudied and that possess the potential to allow us to further deepen our understanding of this behavior.…”