neurochemical and pharmacological experiments have raised the possibility that several neuropeptides including , vasoactive intestinal polypeptide ( vip ) , peptide histidine isoleucine amide ( phi ) , substance p , calcitonin gene-related peptide ( cgrp ) , neurokinin a , cholecystokinin ( cck ) and opioid peptides may be transmitters in afferent pathways to the pelvic viscera .
C0027895
neuropeptides
C0006669
calcitonin gene-related