Sufentanil potentiates the inhibitory effect of epinephrine on intestinal motility

Objective: The aim of our study was to evaluate the effect of the combination of different catecholamines and sufentanil on peristalsis of the isolated guinea pig small bowel in vitro. Design: In vitro study on excised guinea pig small-bowel segments (8-10 segments per substance tested). Setting: Laboratory for experimental studies at the University. Subjects: Isolated guinea pig small-bowel segments. Interventions: Excised segments of guinea pig small bowel were mounted in a tissue bath (37 degreesC) in Tyrode's solution and bubbled with carbogen (95% O-2/5% CO2). The lumina were perfused with Tyrode's solution at 0.5 ml/min. The test drugs (epinephrine, norepinephrine. dobutamine, sufentanil, and a combination of these catecholamines with sufentanil) were added to the tissue bath and peristalsis recorded via changes in the intraluminal pressure. One-way and two-way ANOVA were used for statistical analysis. Measurements and results: All the tested substances, both individually and in combination, inhibited intestinal peristalsis in a dose-dependent manner. High doses resulted in a complete blockade of peristalsis. Preexposure of the segments to sufentanil at 0.1 nM barely influenced the effects of the catecholamines on peristalsis. However, sufentanil at 0.3 nM enhanced the antiperistaltic activity of epinephrine in a supraadditive manner, whereas the effect on norepinephrine and dobutamine was less pronounced. Conclusions: Our experimental data suggest that the combination of epinephrine and sufentanil might be the worst choice for the intensive care setting. This is due to its pronounced inhibitory effect on peristalsis in vitro at moderate and higher concentrations.