Facilitation of sexual behavior in male rats following d-amphetamine-induced behavioral sensitization.
The present study investigated the effect of sensitization, induced by repeated injections of d-amphetamine, on sexual behavior in the naive male rat tested in a drug-free state. Injections of either d-amphetamine (1.5 mg/kg, i.p.) or saline were given every other day for a total of ten injections, and this regimen induced behavioral sensitization of locomotor activity in drug-treated rats. After a 3-week post-drug period, d-amphetamine-treated rats exhibited facilitated sexual behavior, as indicated by shorter latencies to mount and intromit, and a greater percentage of rats copulating. These rats also exhibited a general increase in the amount of copulation. Furthermore, sensitized rats displayed a facilitated acquisition of sexual behavior (i.e. mount and intromission latency <300 s for 3 consecutive days). After repeated sexual experience, rats pre-treated with d-amphetamine also showed an augmented increase in level changes made in anticipation of the presentation of a receptive female. Finally, enhanced sexual behavior was independent of the environment in which repeated administration of d-amphetamine occurred, indicating that facilitation was not a consequence of conditioned associations between drug and test environment. These results demonstrate that behavioral sensitization due to repeated psychostimulant administration can "cross-sensitize" to a natural motivated behavior, such as sex. Furthermore, the subsequent facilitation of anticipatory sexual behavior (i.e. level changes) after repeated experience in rats previously treated with d-amphetamine suggests that behavioral sensitization can influence incentive learning.
Fiorino
D F
DF
University of British Columbia, Department of Psychology, Vancouver, Canada.
Phillips
A G
AG
D000818:Animals; D003213:Conditioning, Psychological / Q000187:drug effects; D003307:Copulation / Q000187:drug effects; D003913:Dextroamphetamine / Q000494:pharmacology*; D015259:Dopamine Agents / Q000494:pharmacology*; D005260:Female; D008297:Male; D051381:Rats; D020318:Rats, Long-Evans; D017207:Rats, Sprague-Dawley; D012725:Sexual Behavior / Q000187:drug effects*
D015259:Dopamine Agents; D003913:Dextroamphetamine