Influence of epinephrine and norepinephrine on intestinal villous blood flow during endotoxemia

Purpose: The objective of this study was to determine the effects of epinephrine and norepinephrine on mucosal villous blood flow in a normotensive model of endotoxemia. Materials and Methods: Thirty-two anesthetized rats were laparotomized, and a jejunal portion was exteriorized and opened by an antimesenteric incision. The jejunal segment was fixed on a plexiglass stage with the mucosal surface upward. Microcirculatory parameters were assessed by intravital videomicroscopy. The animals were randomly assigned to receive one of four treatments: infusion of Escherichia coli lipopolysaccharides (LPS, 2 mg/kg/h) without catecholamine pretreatment (LPS group); or infusion of LPS with epinephrine pretreatment (0.2 mu g/kg/min, start 30 minutes before LPS infusion) (E group), or infusion of LPS with norepinephrine pretreatment (0.2 mu g/kg/min, start 30 minutes before LPS infusion) (IUE group). The control group did not receive either catecholamines or LPS, Mean diameter of central arterioles (D-A) and mean erythrocyte velocity within the arterioles (V-E) were measured 30 minutes before and at 0, 60, and 120 minutes after induction of endotoxemia, Mucosal villous blood flow was calculated from D-A and V-E Results: LPS infusion alone and norepinephrine plus LPS infusion led to a significant vasoconstriction of central arterioles, which was associated with a similar decrease in mucosal villous blood flow. Epinephrine infusion alone led to a vasodilation and an increase in villous blood flow within the first 30 minutes. After induction of endotoxemia, D-A returned to baseline values and villous blood flow was as low as in the LPS and the norepinephrine group after 120 minutes. Conclusion: In this experimental rat model, the catecholamines epinephrine and norepinephrine in a dosage of 0.2 mu g.kg(-1).min(-1) neither diminish nor improve mucosal villous blood flow during the early phase of endotoxemia. Copyright (C) 1999 by W.B, Saunders Company.