AJP - Gastrointestinal and Liver Physiology, Vol 263, Issue 4 474-G479, Copyright © 1992 by American Physiological Society
Intestinal myoelectrical activity and transit time in chronic portal hypertension
J. J. Stewart, H. D. Battarbee, G. E. Farrar and K. W. Betzing
Department of Pharmacology, Louisiana State University Medical Center School of Medicine, Shreveport 71130.
This study was designed to determine the effects of portal hypertension on
intestinal myoelectrical activity and propulsion. In a single surgery,
adult rats were implanted with a serosal electrode at each quarter of the
small intestine, and portal hypertension was produced by calibrated
constriction of the portal vein. To determine intestinal transit, portal
vein-stenosed (PVS) and sham-operated animals were chronically implanted
with a catheter in the proximal small intestine. Transit time was
determined by measuring the progression of radioactive chromium along the
bowel. Studies were conducted 6, 9, and 14 days after surgical preparation.
Portal hypertension was associated with both transient and persistent
changes in intestinal myoelectrical activity during the experimental
period. Slow wave frequency was significantly reduced in the proximal small
intestine on all test days and in the distal small intestine on day 14.
Occurrence of the migrating myoelectric complex was reduced on days 6 and
9. Phase III amplitude was significantly reduced in the distal small
intestine on all test days. Changes in intestinal myoelectrical activity in
PVS animals were not associated with measurable changes in intestinal
propulsion. The results suggest that both transient and persistent changes
in intestinal myoelectrical activity occur during the 2-wk period after
portal vein stenosis. The functional significance of the changes is
unknown.
