Extended paced mating tests induces conditioned place preference without affecting sexual arousal

Area of Science:

• Neuroscience
• Behavioral Science
• Reproductive Biology

Background:

• Sexual arousal can be measured by approach behavior to sexual stimuli.
• Conditioned place preference (CPP) evaluates reward states induced by mating.
• Opioids mediate the reward state induced by paced mating.

Purpose of the Study:

• To compare the rewarding properties of paced mating versus morphine injection.
• To determine if pacing sexual interaction for an extended duration induces CPP.
• To investigate the biological relevance of female-initiated mating spacing.

Main Methods:

• Rats were subjected to paced mating or morphine injection in distinct compartments.
• Preference for compartments was assessed using conditioned place preference (CPP).
• Mating duration and intromission frequency were varied in a second experiment.

Main Results:

• Paced mating induced a stronger reward state (CPP) than a 1mg/kg morphine injection.
• Females pacing sexual interactions for 1 hour or receiving 10-15 paced intromissions developed CPP.
• Extended mating sessions (25 intromissions) with pacing still resulted in CPP.

Conclusions:

• Paced mating is a potent reward stimulus, exceeding the effect of moderate morphine doses.
• The ability of female rats to pace mating is biologically relevant, enhancing reward and sexual arousal.
• Spacing of sexual stimulation during mating is crucial for positive affective states in females.