Leukotriene C4 regulation of splanchnic blood flow during ischemia.
The role of endogenous splanchnic eicosanoids in mediating splanchnic vasoconstriction induced by the leukotriene C4 (LTC4) was examined during mild hemorrhage/reperfusion injury. Male Sprague-Dawley rats were anesthetized and subjected to sham or acute hemorrhage for 30 minutes, to 30 mm Hg, followed by blood reperfusion (SK+R). The superior mesenteric artery was cannulated and removed with its end-organ intestine (SV+SI preparation) and perfused in vitro with oxygenated Krebs-Henseleit buffer. Perfusion pressure was constantly recorded. Net SV+SI release of 6-keto-PGF1 alpha, PGE2 and thromboxane B2 were analyzed by enzyme immunoassay after LTC4 stimulation. Leukotriene C4 increased perfusion pressure and decreased the ratio of 6-keto-PGF1 alpha to thromboxane release (but not PGE2 to thromboxane B2) in the sham group. Hemorrhage/reperfusion increased perfusion pressure and decreased the ratio of 6-keto-PGF1 alpha to thromboxane B2. Mild hemorrhage/reperfusion increased LTC4-induced splanchnic vasoconstriction in part by decreasing the release ratio of endogenous splanchnic PGI2 to thromboxane B2.
Myers
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SI
Department of Surgery, University of Texas Southwestern Medical Center, Dallas.
Hernandez
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R
D000704:Analysis of Variance; D000818:Animals; D006470:Hemorrhage / Q000503:physiopathology*; D007124:Immunoenzyme Techniques; D017997:Leukotriene C4 / Q000494:pharmacology / Q000502:physiology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000503:physiopathology*; D013152:Splanchnic Circulation / Q000187:drug effects / Q000502:physiology*; D013929:Thromboxane B2 / Q000502:physiology*; D014661:Vasoconstriction / Q000502:physiology
D017997:Leukotriene C4; D013929:Thromboxane B2