Eating and drinking in rats with anterior or posterior amygdaloid lesions

Abstract

Electrolytic lesions were placed bilaterally either in the anterior or in the posterior amygdala of albino rats. In terms of comparisons of lesion data with data for animals with corresponding control operations, anterior amygdaloid lesions had no significant influence on either water or overall food intake nor on body weight, while posterior amygdaloid lesions significantly increased water consumption without reliably altering food intake or body weight. It is proposed that the dorsal portion of the anterior amygdala may contain neural elements which facilitate food consumption and inhibit water intake, that the posterodorsal amygdala may contain excitatory elements for food intake, and that the middle portion of the amygdala as a whole may facilitate water intake.In a previous study (Stoller, 1972), relatively large bilateral lesions situated in the amygdaloid complex of rats decreased water intake and produced a loss of body weight. In addition, the data indicated that such lesions might reduce food consumption. Although histological examination of the amygdala and neighboring structures revealed a few instances of damage to the posterior striatum (striatum = caudatoputamen nucleus), a subse· quent investigation (Stoller, 1974) suggested that striatal injury had exerted relatively little, if any, influence on the previous findings.Information has accumulated indicating that amygdaloid influences on eating and drinking are region dependent. Lesions in the dorsomedial amygdala, for example, have resulted in aphagia (Fonberg, 1969), whereas damage involving the basolateral region has produced hyperphagia (Green, Clemente , & De Groot, 1957). Collier and Gault (1969) observed both aphagia and adipsia as a result of lesions involving the medial nuclei. Grossman and Grossman (1963) found that, in rats, water intake was reduced by lesions in the anterior or middle portion of the ventral amygdala, but was increased by posteroventrally placed lesions. More recently Box and Mogenson (1975) observed that lesions in the dorsal region of the central amygdaloid nucleus of the rat produced aphagia and adipsia, whereas lesions in the ventral posterior portion of the lateral amygdala resulted in hyperphagia.In view of such findings the present study sought to extend the analyses of the previous investigations in this laboratory (Stoller, 1972(Stoller, , 1974) to a comparison of the possible effects of anterior and posterior amyg· daloid lesions on eating and drinking.

Amygdala-lesion obesity: what is the role of the various amygdaloid nuclei?

“…Numerous studies have examined the effects of amygdaloid lesions on food intake and body weight in rats, resulting in a similar collection of inconsistent and contradictory results. Initial studies that employed large lesions that destroyed most of the amygdala reported hypophagia and weight loss (4,12,41,56,61,64,65). Subsequent studies of rats with smaller lesions aimed at the basolateral and/or lateral nuclei reported weight gain (8,23,43), no change in body weight (18,28,40,45,58,60), or even weight loss (14).…”

Amygdaloid lesion-induced obesity: relation to sexual behavior, olfaction, and the ventromedial hypothalamus

“…The result was hypophagia and weight loss (e.g., Refs. 5,26,111,179,197,207,208). Subsequent studies that used smaller lesions to target specific amygdaloid nuclei reported inconsistent and conflicting results regarding daily food intake and body weight.…”