Effects of nitric oxide scavenger, carboxy-PTIO on endotoxin-induced alterations in systemic hemodynamics in rats

The present experiments were conducted to clarify the mode of cardiovascular action of carboxy-2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (carboxy-PTIO), a nitric oxide (NO) scavenger, during rat endotoxic shock by determining cardiac output and systemic arterial tone simultaneously. Lipopolysaccharide (LPS) (10 mg/kg, i.v.) decreased systemic blood pressure and cardiac output with transient increases in hematocrit and total vascular resistance. Administration of carboxy-PTIO (1.7 mg x kg(-1) x min(-1), i.v. for 60 min) at 90 min after LPS attenuated further decline in blood pressure and cardiac output without affecting changes in hematocrit or total vascular resistance. It is concluded that carboxy-PTIO attenuates endotoxin-induced hypotension predominantly by maintaining cardiac output in rat experimental endotoxic shock.