Initiation of esophageal secondary peristalsis by slow fluid
infusion in the opossum: effect of hydrochloric acid.
Kusano, Motoyasu, Walter J. Hogan, Ivan M. Lang, Jody L. Bonnevier,
Benson T. Massey, Reza Shaker.
MCW Dysphagia Institute, Departments of Medicine, Radiology, and
Otolaryngology and Human Communication, Medical College of Wisconsin,
Milwaukee, Wisconsin and First Department of Internal Medicine,
School of Medicine, Gunma University, Maebashi, Japan
APStracts 2:0258G, 1995.
We investigated the mechanisms of slow fluid infusion-induced
secondary peristalsis and the effects of hydrochloric acid on this
response. In 13 chronically esophagostomized opossum, acidic and
neutral barium sulfate was infused into the distal esophagus at a
rate of 1.1 ml/min. while recording the esophageal dimension by
videofluoroscopy and esophageal intraluminal pressure concurrently.
The effects of atropine, tetrodotoxin, capsaicin and bilateral
cervical vagotomy on the response to slow fluid infusion were
examined. Acidic barium initiated secondary peristalsis more
frequently and at shorter latency with less increase of pre
-peristaltic intraesophageal pressure than neutral barium (p <
0.05). Atropine abolished secondary peristalsis initiated by neutral
barium. For acidic barium, atropine decreased the incidence of
secondary peristalsis, increased the latency for initiation of
secondary peristalsis, and initiated secondary peristalsis more
distally (p < 0.05). Tetrodotoxin or vagotomy and capsaicin
abolished activation of secondary peristalsis. We concluded that
secondary peristalsis can be stimulated in response to slow
distention by minute amounts of fluid. This peristalsis is atropine
and capsaicin sensitive and vagally mediated. The presence of acid
significantly lowers the threshold for stimulation of secondary
peristalsis induced by slow fluid distention. This effect seems to be
atropine resistant.
Received 19 October 1994; accepted in final form 17 November
1995.
APS Manuscript Number G422-4.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 23 December 95