Amphetamine anorexia by direct action on the adrenergic feeding system of rat hypothalamus.

Abstract

IT has been suggested that amphetamine causes loss of appetite by direct chemical interaction with the hypothalamic feeding system. This is based on the observation that intraperitoneally injected amphetamine is less effective in depressing food intake in rats when they have lateral hypothalamic lesions and have recovered from the post-operative aphagia1. Such evidence is not conclusive, however, because of the possibility that anorexia arises from the action of amphetamine on a part of the system which is necessary to feeding in the normal rat, but which is not necessary to the elicitation of eating by food deprivation in rats which have overcome the aphagia resulting from the lesions. Amphetamine raises the current threshold for elicitation of eating by electrical stimulation of the lateral hypothalamus2,3; this indicates, also indirectly, that it acts there or on efferent systems. Determination of the behavioural effect of administering amphetamine directly into the lateral hypothalamus is a necessary part of establishing the suggestion that anorexia arises primarily from its action there.