ABSTRACT
Sensory nerve stimulation can result in an inflammatory response, which is known as neurogenic inflammation and which is likely due to local release of mediator substances such as neuropeptides. Calcitonin gene-related peptide (CGRP), which is the most potent vasoactive peptide described to date, may also be involved in inflammatory reactions of several tissues. Substance P or related tachykinins and CGRP immunoreactivities occur in the gastrointestinal tract almost entirely in neuronal structures. The colonic content of immunoreactive substance P and CGRP was determined 48 hours after induction of colitis and compared with controls in which saline was given as enema and intravenously. Immunohistochemical studies showed that CGRP and substance P immunoreactivities are present in intrinsic neurons and nerve fibers distributed to all layers of the colon in both control and experimental animals. CGRP-containing fibers were more abundant in association with the enteric plexus, vasculature and mucosa than within the muscle layer.
