AJP - Gastrointestinal and Liver Physiology, Vol 259, Issue 2 226-G232, Copyright © 1990 by American Physiological Society
Effects of enteric neural defunctioning on small bowel motility
C. T. Frantzides, R. E. Condon, B. T. Doumas and J. C. Garancis
Department of Surgery, Medical College of Wisconsin, Milwaukee 53226.
In this study, we investigated the role of intrinsic nerves of the small
intestine on phase III migration of the migrating myoelectric complex.
Fasting myoelectric activity was recorded from the small bowel in
chronically instrumented dogs. Once control experiments were completed, the
animals were divided into two groups and were reoperated. In the first
group of five dogs, a 1.5-g/dl aqueous solution of cobaltous chloride
(shown to induce degeneration of intestinal intrinsic nerves) was infused
close intra-arterially to perfuse a 15-cm segment of jejunum. In the second
group of dogs, a catheter was implanted in a branch of the superior
mesenteric artery supplying a 15-cm segment of intestine. Tetrodotoxin
(0.3-1 micrograms/kg) was infused through the catheter just before the
arrival of phase III activity in the perfused segment. Subsequent to the
fifth postcobalt perfusion day, phase III traversed but did not occur in
the cobalt-treated segment. When tetrodotoxin was injected through the
catheter, spontaneous phasic myoelectric and contractile activities in the
perfused jejunal segment were inhibited, but phase III migration was not
blocked. These findings suggest 1) acute or chronic defunctioning of
enteric nerves does not interrupt phase III migration, but 2) phase III
expression is dependent on the integrity of intrinsic nerves.
