AJP - Gastrointestinal and Liver Physiology, Vol 261, Issue 1 158-G165, Copyright © 1991 by American Physiological Society
Gastric contractions produce phasic changes in perfusion pressure
J. G. Wood and L. Y. Cheung
Department of Surgery, University of Kansas Medical Center, Kansas City 66103.
This study examined the relationship between motility and perfusion
pressure of an ex vivo segment of the canine stomach perfused at constant
flow. Changes in luminal pressure were used to quantitate contractile
force. Under control conditions, spontaneous contractions increased luminal
pressure by 18.8 +/- 1.1 mmHg and gastric perfusion pressure by 14.2 +/-
0.8 mmHg. Changes in luminal and perfusion pressures during contractions
were highly correlated (r2 = 0.963, P less than 0.0001, 109 observations in
5 dogs). In separate studies, we assessed the effects of atropine,
neostigmine (an acetylcholinesterase inhibitor), and bethanechol (a
muscarinic cholinergic agonist). Atropine attenuated the
peristaltic-induced changes in perfusion pressure in a
concentration-dependent manner (10(-9) to 10(-6)M) with nearly total
inhibition at the highest dose. Neostigmine (10(-9) to 10(-6) M) and
bethanechol (10(-8) to 10(-5) M) stimulated contractions, resulting in
dose-related increases in luminal and perfusion pressures. Our results
demonstrate that cholinergic-dependent contractions produce marked, phasic
changes in gastric perfusion pressure.
