Shock : molecular, cellular, and systemic pathobiological aspects and therapeutic approaches : the official journal the Shock Society, the European Shock Society, the Brazilian Shock Society, the International Federation of Shock Societies
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Excess production of NO and activation of vascular ATP-sensitive potassium (K(ATP)) channels are implicated in the hypotension and vascular hyporeactivity associated with endotoxic shock. Using a fluid-resuscitated endotoxic rat model, we compared the cardiovascular effects of an iNOS inhibitor and two distinct inhibitors of the K(ATP) channel. Endotoxin (LPS) was administered to anesthetized, spontaneously breathing, fluid-resuscitated adult male Wistar rats, in which MAP, aortic and renal blood flow, and hepatic microvascular oxygenation were monitored continuously. ⋯ We conclude that inhibition of the K(ATP) channel via the pore-forming, but not the sulfonylurea receptor subunit, increases blood pressure in a short-term endotoxic model. However, this was not accompanied by any improvement in macrocirculatory or microcirculatory organ blood flow nor reversal of metabolic acidosis. It therefore remains uncertain whether the iNOS pathway or the K(ATP) channel represents a potential target for drug development in the treatment of endotoxic shock.
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Hemoglobin vesicles (HbVs) are artificial oxygen (O2) carriers that encapsulate concentrated hemoglobin (Hb) solution in phospholipid vesicles (liposomes). Recent reports on cytoprotective effects of exogenous carbon monoxide (CO) urged us to test infusion of CO-bound HbV (CO-HbV) and red blood cells (CO-RBC) in hemorrhagic-shocked rats to improve tissue viability over that of O2-bound HbV (O2-HbV) and O2-bound RBC (O2-RBC). Male Wistar rats were anesthetized with 1.5% sevoflurane inhalation (FiO2 = 21%) while spontaneous breathing was maintained. ⋯ They reduced oxidative damage to organs in comparison to O2-HbV and O2-RBC. Adverse and poisonous effects of CO gas were not evident for 6 h in this experimental model. Further study is necessary to clarify the neurological impact of a longer observation period for eventual clinical applications.