Adenosine plays a role in food-induced jejunal hyperemia.

The aim of this study is to determine the role of adenosine in postprandial hyperemia in the jejunum of anesthetized dogs. The effect of two adenosine antagonists, aminophylline and 8-phenyltheophylline, on the vascular responses to intra-arterial infusion of adenosine and luminal placement of food was determined. The effect of aminophylline on the food-induced hyperemia was found to be dependent on motility. Aminophylline had no effect on the hyperemia when motility was high but inhibited the hyperemia when motility was low. Vasodilations produced by intra-arterial infusions of adenosine, however, were attenuated by aminophylline regardless of the level of motility. The more potent and specific adenosine antagonist, 8-phenyltheophylline, also inhibited both adenosine- and food-induced vasodilations. This inhibition occurred whether the intestinal motility was high or low. In conclusion, adenosine receptor blockade inhibits jejunal food-induced hyperemia, and adenosine may play a role in the hyperemia. The effect of aminophylline was complicated by motility.