A glucagon-secretin-like peptide stimulates the intrinsic nervous plexus of guinea pig gallbladder.

Experientia1990PMID: 1971797

Plain Language Summary

Researchers investigated whether VIP is the neurotransmitter responsible for controlling guinea pig gallbladder muscle activity. Surprisingly, a GRF analog thought to antagonize VIP actually stimulated gallbladder contractions, while a standard VIP antagonist had no effect, leading to the conclusion that the gallbladder's inhibitory nerve signaling is mediated by a different member of the glucagon-secretin peptide family rather than VIP itself.

Abstract

The role of vasoactive intestinal peptide (VIP), as a possible neurotransmitter of the intrinsic nerve plexus in the guinea pig gallbladder, was investigated by monitoring spontaneous contractile activity. VIP receptor antagonist (4 Cl-D-Phe6, Leu 17)-VIP did not produce any effect on muscular tone and spontaneous activity, whereas (N-Ac-Tyr1, D-Phe2)-GRF-(1-29)-NH2, (14-GRF analog), which is known to stimulate digestive enzyme secretion by interacting with the VIP-preferring receptors, greatly increased the amplitude and frequency of waves as well as the muscular tone. Since VIP receptor antagonist acts selectively as a competitive antagonist for the action of VIP, we conclude that the gallbladder inhibitory intrinsic plexus neurotransmitter is not VIP, but a member of the glucagon-secretin family of peptides.

Authors

Greco, A V; Mancinelli, R; Mingrone, G; Racanicchi, C