Facilitation of feeding by nucleus accumbens amphetamine injections: latency and speed measures

Food-deprived rats were offered food in small meal segments, and latency to initiate feeding and time to complete it were recorded for each segment. Bilateral microinjections of d-amphetamine into nucleus accumbens dramatically increased the mean speed with which meal segments were eaten, but had no reliable effect on mean latency to initiate eating of new segments; l-amphetamine had similar but weaker effects. While mean eating speed was increased, this increase resulted from a decrease in the frequency of slow trials and not from an increase in the absolute speed of the fastest trials. These data suggest that amphetamine facilitates feeding by some other means than simple improvement of the motoric capacity of the animal, and they indicate that nucleus accumbens is an important site for amphetamine's established but not widely appreciated facilitory effects on feeding.