Strain Differences in Sexual Behavior of the Male Rat1)

Abstract

AbstractThe sexual behavior of four strains of inbred rats was studied. These strains are characterized by differences in problem solving ability and in the levels of brain acetylcholine and cholinesterase. I. The S1, and S3 strains appeared similar motivationally. The S3 animals had more difficulty in achieving intromission, and ejaculated after fewer intromissions (14.6 vs. 7.1). The S3 males resumed mating sooner after ejaculation than did the S1 males (410 sec. vs. 293 sec.). 2. The RDH and RDL strains were homogeneous on all measures of sexual performance. These strains were similar to the S1 strain in latency measures, but were like the S3 strain in the number of intromissions needed for ejaculation. 3. The data were interpreted to mean that intromission frequency is particularly likely to be under genetic control, and that the ejaculation process may be related to the absolute levels and relative balance of acetylcholine and cholinesterase within the central nervous system.