Introduction: Dopamine (DA) is commonly used in shock. Vasodilator doses of DA decrease GI mucosal oxygen uptake even though total intestinal blood flow is increased1. Neuropeptide Y(NPY) has a potent mesenteric vasoconstrictive effect. We hypothesized, that DA induced alteration in GI mucosal oxygen uptake would lead to increased mesenteric lactate production and translocation of gut endotoxins. We also considered a role for NPY in the mesenteric arteriolar constriction.

Methods: The femoral artery (FA) and vein were cannulated in 6 anesthetized male Wistar rats. A directional Doppler flow probe was placed around the superior mesenteric artery (SMA) via midline laprotomy. Arterial blood pressure, heart rate, and flow were continuously recorded during the rest period of 10 min. and throughout the 1hr. period of 3mcg/kg/min DA infusion. Blood samples (0.6ml) for the measurement of lactic acid (mmol/l), endotoxin (Eu/ml) and NPY (pcg/ml) were obtained from FA and SMV before(control) and at the end of DA infusion.

Results: Values as (mean±SEM). * =p<0.05 vs control, #=p<0.05 vs FA(Student's t test).

Conclusion: Low dose DA infusion resulted in an increase in transmesenteric lactate and endotoxin levels, suggesting that there is a decrease in mucosal oxygen uptake leading to GI hypoxia and disruption of mucosal integrity despite an increase in SMA blood flow. The increase in NPY levels suggests that NPY mediated arteriolar constriction may be involved in the alteration of GI mucosal oxygen uptake. Table

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