Effects of Extrinsic Denervation on the Fluorescence of Monoamines in the Small Intestine of the Cat

A hlman , H., L. E nerback , J. K ewenter and B. S torm . Effects of extrinsic denervation on the fluorescence of monoamines in the small intestine of the cat. Acta physiol. scand. 1973. 89. 429–435. The effects of section of the nerves supplying the small intestine in the cat were studied in vivo at different times after the operation. Before denervation, biopsies from the jejunum and ileum were studied by a fluorescence method in order to observe the adrenergic innervation and the presence of 5‐hydroxytryptamine (5‐HT). In addition to the adrenergic fibres terminating around the ganglion cells of the intestinal nervous plexuses, other adrenergic fibres were seen in close connection with the muscle fibres in both muscular layers. The only location of 5‐HT seemed to be in the enterochromaffin cells of the mucosa. After nerve section the completeness of the denervation was established in an acute experiment by means of electrical stimulation of the vagal and splanchnic nerves while registering the motility of a jejunal and an ileal loop. Afterwards the small intestinal wall was studied with the same histochemical fluorescence method. No changes were found in the towel habits or in the general state of nutrition of the animals. The intestinal adrenergic innervation completely disappeared after denervation. The adrenergic innervation does not seem to be necessary for adequate peristaltic activity in the small intestine. 5‐HT did not disappear after denervation but was found unchanged in the enterochromaffin cells.