Gastric compliance and motility in the portal hypertensive rat

In an ex vivo rat model, we compared the intraluminal pressure response of both the whole stomach and the antrum to progressive intraluminal distension in portal hypertensive and sham-operated rats. In both groups, this response featured a biphasic change in tone with superimposed phasic pressure waves. While the tonic pressure response to distension (reflecting gastric compliance) was similar in both groups, the frequency and amplitude of antral phasic pressure waves (reflecting antral motility) were greater in the portal hypertensive animals. These studies indicate that portal hypertension does not alter gastric compliance but is associated with an exaggerated antral motor response to distension, suggesting that this latter mechanism, rather than impaired accommodation, may explain the accelerated gastric emptying described previously in the portal hypertensive rat.