[Neural regulation of the secretion of the small and large intestines]

The small bowel and the colon are supplied by a dense network of nerves. Nervous control of secretion is influenced by peripheral and central nerves. The small and large intestine are tonically inhibited by the enteric nervous system, in particular by the submucous plexus, to maximally absorb fluid and electrolytes. Choleratoxin induced intestinal secretion may be suppressed by central opiate receptors, and central gamma-aminobutyric acid receptors may inhibit intestinal absorption. Besides the classical neurotransmitters acetylcholine and noradrenalin, which stimulate and inhibit, respectively, secretion, a large number of regulatory peptides and other substances which mainly act as cotransmitters and neuromodulators affect mucosal transport in the small and large intestine. Secretion induced by nerves appears to play a major role in diabetic and infectious diarrhea. The nervous control of secretion in the small and large intestine is an interesting area of current research in intestinal transport. So far already, the results shed new light in a better understanding of intestinal pathophysiology, and they point towards new therapeutic modalities in diarrhea and constipation.