Effects of alcohol on the sexual motivation of the male rat.

Previous research measuring the effects of alcohol on sexual behavior has primarily focused on its effects on copulation. The present experiment was designed to investigate the effects of alcohol on the sexual motivation of the male rat by requiring operant responding to gain access to a sexually receptive female. A novel apparatus was used that allowed both visual and olfactory cues from an estrous female to reach the male. Lever presses resulted in the opening of a door that permitted the male rat to enter an adjacent chamber where a receptive female was located. Treatment with low to moderate doses of alcohol (0.5 g/kg and 1.0 g/kg) resulted in increased latencies to emit the first response of the males working for access to females, but did not affect response rate or subsequent mount or ejaculation latencies, when these males were allowed access to the receptive female. Furthermore, alcohol failed to show any response-reinstating or disinhibitory effects when tested following a period of nonreinforced extinction trials. An additional experiment, in which rats received equivalent doses of alcohol, revealed no decrease in spontaneous locomotion. Taken together, these data suggest that the response-reducing effects of alcohol are probably not a result of general drug-induced reductions in activity, but rather an attenuating action of the drug on sexual motivation.