The effect of bilateral amygdaloid nucleus lesions on rat small bowel crypt cell kinetics.

Previous investigators have found that central nervous system lesions, in particular lesions of the hypothalamus, may increase the crypt cell mitotic rate in the rat small bowel. Since the amygdaloid nuclei form part of the limbic system (the "visceral brain") and have functional neural connections with the hypothalamus the effect of bilateral electrocoagulation lesions of the amygdaloid nuclei on crypt cell mitotic rate in the rat small bowel was investigated, using a stathmokinetic technique. Bilateral amygdaloid lesions were found to be associated with a marked increase in crypt cell mitotic rate in the proximal jejunum and distal ileum. Consideration of the neural connections of the amygdaloid nuclei suggests that these effects may possibly be mediated via the hypothalamus and the autonomic nervous system. The effects of lesions of other parts of the limbic system on crypt cell mitotic rate will be published subsequently.