Effects of adenosine infusion on gastric emptying in healthy volunteers

A low dose of systemic adenosine infusion has been shown to induce antinociception in clinical experimental studies as well as in patients. There is no clinical information about the effect of adenosine on the motility of the gastrointestinal tract. The aim of this study was therefore to evaluate the effect of exogenous adenosine administration on gastric emptying in man.

Ten healthy male volunteers (22-45 yrs) were included in a placebo-controlled, double-blind, randomised, cross-over study, where the experiments were separated by at least one week. During one session the volunteers received a continuous intravenous infusion of adenosine (50 micrograms.kg-1.min-1) initiated 15 min prior to the test of gastric emptying (a standard test meal, followed by oral acetaminophen, 2 g) and lasting throughout the experiment (2 h). During the other experimental session an infusion of saline was given. Acetaminophen absorption test was used as an indirect measure of the rate of gastric emptying. Venous acetaminophen concentration curves were produced and the maximum acetaminophen concentration (Cmax), the time to reach the maximum concentration (Tmax), and the area under the serum acetaminophen concentration time curve from 0 to 60 min (AUC60) were calculated.

There was no difference between placebo and adenosine in Cmax (197 vs. 199 mumol.L-1, P = 0.80), Tmax (23 vs. 45 min, P = 0.14), AUC60 (9633 vs. 9111 min.mumol.L-1, P = 0.28).

The results demonstrate that adenosine in a clinically antinociceptive dose of 50 micrograms.kg-1.min-1 does not affect the rate of gastric emptying in healthy volunteers.