Electrophysiological Study on the Effect of the Limbic System Stimulation on Intestinal Movement in Rabbits

Abstract

Irritable bowel, syndrome (IBS) is a disease characterized by increased intestinal movement with abdominal pain and changes in bowel habit (either diarrhea or constipation), the clinical expression of which seems to be easily influenced by mental factors such as stress or emotion. To clarify the relationship between intestinal movement and mental activity, we studied the effect of electrical stimulation of subcortical nuclei, especially the limbic system, on intestinal movement. We used the balloon method on the ascending colon of rabbits. Acceleration of intestinal movement was found with 3 Hz stimulation to the corticomedial division of the amygdaloid nucleus (c-AMYG) and cortex pyriformis, and 100 Hz stimulation to the basolateral division of the amygdaloid nucleus (b-AMYG) and caudate nucleus (CAU). The acceleration was found to be due to the tonic effect of parasympathetic nerves. On the other hand, inhibition of intestinal movement was found with 100 Hz stimulation to c-AMYG,8 Hz stimulation to b-AMYG and 3Hz stimulation to b-AMYG and CAU. Although the inhibitory impulses were demonstrated to pass through the splanchnic nerve, the existence of some degree of adrenal influence was suggested.