Vasoplegia in sepsis depends on the vascular system, vasopressor, and time-point: a comparative evaluation in vessels from rats subjected to the cecal ligation puncture model

We evaluated the effects of phenylephrine, norepinephrine, angiotensin II, and vasopressin in mesenteric, renal, carotid, and tail arteries, and in perfused mesenteric vascular bed from rats subjected to the cecal ligation and puncture (CLP) model of sepsis. Phenylephrine and angiotensin II were less efficacious in mesenteric arteries from the CLP 6 h and CLP 18 h groups than in preparations from non-septic animals, but no differences were found for norepinephrine and vasopressin between the preparations. In renal arteries, none of the vasoconstrictors had impaired activity in the CLP groups. Nonetheless, carotid arteries from the CLP 18 h group presented reduced reactivity to all vasoconstrictors tested, but only phenylephrine and norepinephrine had their effects reduced in carotid arteries from the CLP 6 h group. Despite the reduced responsiveness to phenylephrine, tail arteries from septic rats were hyperreactive to vasopressin and norepinephrine at 6 h and 18 h after the CLP surgery, respectively. The mesenteric vascular bed from CLP groups was hyporeactive to phenylephrine, norepinephrine, and angiotensin II, but not to vasopressin. The vascular contractility in sepsis varies from the well-described refractoriness, to unaltered or even hyperresponsiveness to vasoconstrictors, depending on the vessel, the vasoactive agent, and the time period evaluated.