Appetitive sexual behavior in male rats: 2. sexual reward and level-changing behavior.

Anticipatory level-changing behavior is a form of appetitive sexual behavior displayed by male rats prior to introduction of a female in a bilevel testbox. Analysis of this level-changing behavior may serve as assessment of sexual motivation. Because ejaculation affects appetitive aspects of sexual behavior, measures purporting to assess sexual motivation should be effected by ejaculation. We observed that ejaculation prior to testing reduced the number of anticipatory level changes of a male rat. This reduction was greater when tested after two than after one ejaculation. Our results support the concept that analysis of anticipatory level-changing behavior can be used to measure sexual motivation.