Effects of amphetamine and phenylpropanolamine on food intake in rats with ventromedial hypothalamic or dorsolateral tegmental damage

Female rats with sham lesions or lesions of the ventromedial hypothalamus (VMH) or the dorsolateral tegmentum (DLT) were maintained at 80% normal body weight to minimize possible group differences in hunger motivation. VMH rats displayed attenuated amphetamine (0.5, 1.0, and 2.0 mg/kg) anorexia when fed a high-fat test diet but normal anorexia when fed a pellet test diet whereas DLT rats displayed attenuated amphetamine anorexia when fed either test diet. Neither VMH nor DLT rats displayed attenuated anorexia to phenylpropanolamine (5.0, 10.0, and 20.0 mg/kg), an analogue of amphetamine. These results are discussed in terms of an amphetamine-activated arousal mechanism within the DLT.