ObjectiveVasopressin has been used to treat arterial hypotension associated with hyperdynamic vasoplegic states, but detrimental effects on splanchnic circulation have been reported. We tested the effects of a low-dose vasopressin analogue, terlipressin (6 &mgr;g/kg), on systemic and splanchnic hemodynamics in fluid-challenged endotoxic rats (lipopolysaccharide, 30 mg/kg in 1 hr).DesignProspective, randomized, controlled experimental study with repeated measures.SettingInvestigational animal laboratory.SubjectsA total of 77 rats were divided into five groups: group C, control (17 rats); group E, LPS (18 rats); group EF, LPS plus fluid challenge (18 rats); group EFT, LPS plus fluid challenge plus terlipressin (18 rats); and group ET, LPS plus terlipressin (seven rats).InterventionsRats were anesthetized, mechanically ventilated, and instrumented to measure heart rate, mean arterial pressure, and abdominal aortic and mesenteric vein indexed blood flows; ileal microcirculation was assessed by laser Doppler. After LPS infusion, rats experienced an endotoxic shock and were resuscitated after the allocation group. The fluid challenge was targeted to maintain mean arterial pressure of >90 mm Hg and aortic blood flow at baseline values.Measurements and Main ResultsTerlipressin significantly (p< .05) increased mean arterial pressure without decreasing indexed aortic blood flow and heart rate in the fluid-challenged endotoxic rats (EFT) compared with EF rats and had detrimental effects in hypodynamic endotoxic rats (ET). Fluid challenge significantly (p< .05) increased mesenteric vein blood flow in both the EF and EFT groups, and terlipressin had no detrimental effect on mesenteric blood flow. Terlipressin significantly (p< .05) increased ileal microcirculation in fluid-challenged endotoxic rats (EF and EFT) but not in hypodynamic endotoxic rats (E and ET).ConclusionLow-dose terlipressin in fluid-challenged endotoxic rats improved systemic and splanchnic hemodynamics and improved the ileal microcirculation.