AJP - Gastrointestinal and Liver Physiology, Vol 257, Issue 3 380-G385, Copyright © 1989 by American Physiological Society

ARTICLES

VIP and acetylcholine: neurotransmitters in esophageal circular smooth muscle

J. Behar, V. Guenard, J. H. Walsh and P. Biancani
Department of Medicine, Rhode Island Hospital, Providence.

Vasoactive intestinal polypeptide (VIP) and acetylcholine were evaluated as possible inhibitory and excitatory neurotransmitters in the cat esophageal circular smooth muscle. Circular muscle strips 2 mm in thickness were obtained from 1 to 3.4 cm above the lower esophageal sphincter and tested in vitro. Muscle strips contracted with bethanechol (10(-5) M) were relaxed by electrical stimulation (0.5-5 Hz) and by VIP (10(-8)-10(-6) M). Relaxation induced by electrical stimulation was blocked by tetrodotoxin, whereas VIP-induced relaxation was not affected. Highly specific VIP antiserum (5%) antagonized both VIP and electrically induced relaxation, and the antagonism was eliminated when the antiserum was neutralized with VIP (10(-6.5) M). Dopamine (10(-4) M) reduced the relaxation induced both by exogenous VIP and by electrical stimulation but did not affect the relaxation caused by sodium nitroprusside (10(-8)-10(-5) M). In untreated strips, physostigmine (10(-10)-10(-8) M) enhanced the off contraction in response to electrical stimulation, whereas atropine caused a dose-dependent reduction with complete abolition at 10(-4) M. These data suggest that in the esophagus inhibition and excitation are mediated by distinct mechanisms: VIP mediates inhibition and acetylcholine is responsible for the off contraction in response to electrical stimulation.

This article has been cited by other articles:

				L. Cheng, W. Cao, C. Fiocchi, J. Behar, P. Biancani, and K. M. Harnett Platelet-activating factor and prostaglandin E2 impair esophageal ACh release in experimental esophagitis Am J Physiol Gastrointest Liver Physiol, September 1, 2005; 289(3): G418 - G428. [Abstract] [Full Text] [PDF]

				W. Cao, L. Cheng, J. Behar, C. Fiocchi, P. Biancani, and K. M. Harnett Proinflammatory cytokines alter/reduce esophageal circular muscle contraction in experimental cat esophagitis Am J Physiol Gastrointest Liver Physiol, December 1, 2004; 287(6): G1131 - G1139. [Abstract] [Full Text] [PDF]

				A. Muinuddin, S. Xue, and N. E. Diamant Regional differences in the response of feline esophageal smooth muscle to stretch and cholinergic stimulation Am J Physiol Gastrointest Liver Physiol, December 1, 2001; 281(6): G1460 - G1467. [Abstract] [Full Text] [PDF]

				H. G. Preiksaitis and L. G. Laurier Pharmacological and Molecular Characterization of Muscarinic Receptors in Cat Esophageal Smooth Muscle J. Pharmacol. Exp. Ther., May 1, 1998; 285(2): 853 - 861. [Abstract] [Full Text]

				W. G. Richards, J. S. Stamler, L. Kobzik, and D. J. Sugarbaker Role of nitric oxide in human esophageal circular smooth muscle in vitro J. Thorac. Cardiovasc. Surg., July 1, 1995; 110(1): 157 - 164. [Abstract] [Full Text]