Effect of Vasoactive Intestinal Polypeptide (VIP) on the Lower Esophageal Sphincter Pressure (LESP)

Abstract

Vasoactive intestinal polypeptide (VIP) is a highly basic peptide which resembles secretin, glucagon, and to some extent gastric inhibitory polypeptide (GIP). First isolated from porcine small intestine, VIP exerts a variety of biological actions (1-5).The lower esophageal sphincter (LES) remains in a continuous state of closure at rest and opens on swallowing in order to let the bolus pass into the stomach (6). The mechanisms which control the resting sphincter pressure and its relaxation are not properly understood.Recent studies have shown that VIP is widely distributed throughout the gastrointestinal tract and causes relaxation of various smooth muscles of the gastrointestinal tract (3,7). Furthermore, it has been specifically localized in the esophagus in the myenteric plexus as well as in the muscular area (7,8). The purpose of the present investigation was to study the effect of VIP on LES smooth muscle in vivo.Materials and methods. The present studies were conducted in 11 opossums (Didelphis virginiana) because in this species the lower end of the esophagus, including LES, is smooth muscle and resembles that of man (9). The animals were anesthetized by intraperitoneal administration of pentobarbital sodium (40 mg/kg) and strapped supine on an animal board. The animals were breathed with a mechanical respirator (Harvard Apparatus Co., Millis, Mass.). The brachial vein was cannulated for intravenous administration of agents. The animals were made to swallow a specially designed catheter system (10) which consisted of four polyvinyl catheters fused together with I Send reprint requests to Dr. Satish Rattan, Department of Internal Medicine, University of Texas Health Science Center, 5323 Harry Hines Blvd., Dallas, Texas 75235.tetrahydrofuran, and interposing central idle polyvinyl tubing. All of these catheters had side openings at the distal end 1 cm apart. The proximal ends of these catheters were connected to Statham pressure transducers. All of these catheters were constantly perfused with bubble-free water under pressure, as already described (1 0). The perfusion rate of water under the present arrangement was 0.33 ml/min. The compliance in this system of perfusion even at a lower rate of water perfusion was insignificant. Initially, the catheter assembly was introduced into the stomach. All the pressures were recorded on a Beckman dynograph recorder (Model R411, Beckman Instruments, Schiller Park, Ill.) through Statham pressure transducers (Statham, Model P23Db, Statham Instruments, Oxnard, Calif.). One of the common carotid arteries was cannulated for direct measurement of blood pressure. At this point, the abdominal cavity of the animals was exposed employing midline laparotomy incision. The catheter assembly was slowly pulled until one of the middle openings recorded pressures from the high pressure zone of the LES, while the lower ends of the esophagus and upper part of the stomach were under direct vision. The catheter assembly openings lying proximal and distal to the opening resting in the LES r...

Relaxation of Muscle Strips from the Reticular Groove and Reticulo‐Omasal Orifice by Vasoactive Intestinal Peptide (VIP)

“…This observation suggests that VIP acts on the smooth muscle of the reticular groove directly. It is consistent with numerous findings showing that the relaxing effect of VIP on smooth muscle in various parts of the G. I. tract occurred only postjunctually (RATTAN et al, 1977;UDDMAN et al, 1978;BITAR and MAKHLOUF, 1982;BIANCANI et al, 1984;DENAC et al, 1987). We conclude that VIP could be involved in the reticular groove mechanism as NANC inhibitory transmitter.…”

Vasoactive intestinal polypeptide. A neurotransmitter for lower esophageal sphincter relaxation.

“…VIP causes LES relaxation by direct action on the LES muscle because the neural blocker, tetrodotoxin, does not block this effect (14,15). VIP may be an inhibitory neurotransmitter.…”

Systemic Sclerosis: Successful Treatment of Ulcerations, Pain, Raynaud’s Phenomenon, Calcinosis, and Dysphagia by Transcutaneous Nerve Stimulation

“…Thus, the vasoactive intestinal polypeptide (VIP) has been demonstrated in the eso phagus (2), where it appears to be localized in intrinsic neurons found most densely in the region of the gastroesophageal junction (2). VIP is a potent relaxant of the lower esophagus and lower esophageal sphincter (3, 7, 20, 23), due to a direct action on the sphincter muscle (3,7,20). Since inhibition is an essential feature in the propagation of peristaltic waves, loss of relaxation abilities may impair peristalsis.…”