Involvement of tachykinins in intestinal inflammation.

The tachykinins, substance P, neurokinin A and neurokinin B are small peptides expressed in the extrinsic primary afferent nerve fibers and enteric neurons of the gut. Tachykinins exert a variety of biological actions mediated by three distinct receptors, termed NK1, NK2 and NK3, and at the gastrointestinal level these peptides influence motility, electrolyte and fluid secretion and tissue homeostasis. Several intestinal disorders are associated with changes in the expression of the tachykinin system. Thanks to biological studies and receptor cloning, new selective tachykinins antagonists are now available and have been shown to be active in experimental gut disorders. Some of them are now under clinical trial in inflammatory bowel diseases and the irritable bowel syndrome. The body of preclinical data so far available seems to indicate that tachykinin antagonists might be a new therapeutic tool in the treatment of gut disorders.