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.
KeywordsSensory Nerve Vasoactive Intestinal Polypeptide Longitudinal Muscle Human Small Intestine Longitudinal Strip
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