Localization of calcitonin gene-related peptide-like immunoreactivity in neurons of the rat gastrointestinal tract.

Calcitonin gene-related peptide (CGRP)-like immunoreactivity was localized in neuronal processes and somata of the rat gastrointestinal tract. Varicose processes were observed in the myenteric and submucosal plexuses, smooth muscles, submucosa, mucosa and around blood vessels. Immunoreactive somata were visualized in the myenteric and submucosal ganglia of the intestine in colchicine-treated rats. These observations, together with previous neuroanatomical and pharmacological studies, suggest that CGRP may be involved in regulatory functions of the gastrointestinal tract.