Tolerance in the depression of intake when amphetamine is added to the rat's food

The depression of intake initially seen when a rat is placed on an amphetamine adulterated diet disappears over a week at the dose level of 0.2 mg amphetamine per gram of chow. The decreased effectiveness of amphetamine is attributable primarily to accruing deprivation rather than to either behavioral or pharmacological tolerance. Ventromedial hypothalamic lesions attenuate the tolerance, whereas lateral hypothalamic lesions decrease the basic anorexigenic effect of amphetamine.