Male Hatano low-avoidance rats show more active sexual behavior with lower plasma testosterone than high-avoidance rats

Abstract

Two inbred strains of Sprague-Dawley rats, known as the Hatano high- and lowavoidance animals (HAA and LAA respectively), have been selectively bred for high versus low rates of avoidance responses in a shuttle-box avoidance task. To investigate differences in the sexual behavior of Hatano rats, male HAA, LAA and SD rats were tested from 12 to 15 weeks of age. LAA rats exhibited more rapid and frequent sexual behavior than HAA or SD rats, and such differences increased with repeated sexual experience. Plasma testosterone levels tended to be lower in LAA rats than in HAA or SD rats, suggesting that active sexual behavior in LAA rats is not related to these levels. Strain differences in mating behavior between HAA and LAA rats may be caused by emotional responses to novelty.