Vagally dependent protective action of calcitonin gene-related peptide on colitis

This work evaluates the mechanism of action of calcitonin gene-related pept ide (CGRP) on colitis. Firstly, Wistar rats were intracolonically instilled with trinitrobenzenesulfonic acid (TNBS) and IV treated by either alpha CG RP, or hCGRP(8-37), or by vehicle. The inflammatory level was evaluated 8 h and 4 days after TNBS. Secondly, intracerebroventricular alpha CGRP was as sessed on the 4-day group with colitis. Finally, IV alpha CGRP was administ ered in vagotomized animals, and tested on the 4-day group with colitis. Co litis was aggravated by hCGRP(8-37), and decreased by peripheral but not ce ntral alpha CGRP. alpha CGRP was inactive on inflammatory parameters in vag otomized colitic rats. This suggests that endogenous peripheral CGRP has an anti-inflammatory role in TNBS-induced colitis, depending upon the integri ty of the vagus. (C) 1999 Elsevier Science Inc. All rights reserved.