Effects of small amygdaloid lesions on pancreatic exocrine secretion

To investigate the role of the amygdala in central regulation of pancreatic exocrine secretion, the effects of electrolytic lesions on pancreatic secretion were studied in rats. Small bilateral electrolytic lesions in amygdaloid body restricted to basolateral, medial and central nuclei were produced. Eight days after the lesions, bile-pancreatic juice was collected following anesthetization with urethane and chloralose. Basal secretion and secretion stimulated by exogenous pancreozymin and secretin were evaluated in terms of amylase output. In the group with basolateral nucleus lesions, both basal and stimulated secretion were significantly increased. After medial nucleus lesions, mean body weight was reduced to 59% of initial, and basal and stimulated secretion were significantly lower than in the control group and also significantly lower than in an unoperated group, whose mean body weight was reduced to the same level as that of the medially lesioned group by restricting daily food intake. After lesions of the central nucleus, basal secretion was significantly increased, while stimulated secretion was not affected. These results indicated that the amygdala is involved in regulating pancreatic exocrine secretion and that its various nuclei exert different effects.