Vasoactive Intestinal Polypeptide (VIP) and the Specific Motor Response to Capsaicin of the Human Isolated Ileum
Capsaicin, the pungent ingredient of many red peppers, has been shown to possess a selective stimulant action on certain neuropeptide-containing primary afferents which are widely distributed in the gastrointestinal tract of several species (Maggi and Meli 1988 and Holzer 1988 for reviews). On isolated gut segments from rats or guinea pigs, capsaicin exerts a variety of motor responses (contraction, relaxation or both) which depend upon the release from sensory nerves of certain neuropeptides, such as tachykinins or calcitonin gene-related peptide (CGRP) (see as examples Barthó et al., 1987; Maggi et al., 1986; 1988a). A specific feature of the action of capsaicin on sensory nerves is represented by desensitization, which means that after a single application of a maximally effective concentration of capsaicin the sensory fibers become unresponsive to subsequent applications of this drug.
KeywordsPolypeptide Neurol Lution Calcitonin Ileal
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- Angel, F., Go, V.L.W., Schmalz, P. F., Szurszewski, J. H., 1983, VIP: a putative transmitter in the canine gastric muscularis mucosa, J.Physiol. (London) 341:641.Google Scholar
- Maggi, C.A., Manzini, S., Giuliani, S., Santicioli, P., and Meli, A., 1986, Extrinsic origin of the capsaicin-sensitive innervation of the rat duodenum: possible involvement of calcitonin gene-related peptide (CGRP) in the capsaicin-induced activation of intramural nonadrenergic noncholiner-gic neurons, Naunyn. Schmied. Arch. Pharmacol. 3 34:172.CrossRefGoogle Scholar
- Maggi, C.A., Patacchini, R., Santicioli, P., Giuliani, S., Turini, D., Barbanti, G., Beneforti, D., Misuri, D., Meli, A., 1989b, Human isolated small intestine: motor responses of the longitudinal muscle to field stimulation and exogenous neuropeptides, Naun. Schmied. Arch. Pharmacol. 339:415.CrossRefGoogle Scholar
- Maggi, C.A., Santicioli, P., Patacchini, R., Geppetti, P., Giuliani, S., Astolfi, M., Baldi, E., Parlani, M., Theodorsson, E., Fusco, M., and Meli, A., 1988c, Regional differences in the motor response to capsaicin in the guinea-pig urinary bladder: relative role of pre- and postjunctional factors related to neuropeptide-containing sensory nerves, Neuroscience 27:675.PubMedCrossRefGoogle Scholar