Endotoxins play important roles in the pathophysiologic alterations associated with sepsis so we examined the effects of volatile anesthetics on vascular smooth muscle contractile function in LPS-treated rat aorta.

Fifty male Sprague-Dawley rats(250~300 gm) were made septic by intraperitoneal injection of lipopolysaccharide(1.5 mg/kg). Cumulative doses of phenylephrine and norepinephrine(10 -8~10 -5M) were added to construct a contraction response curve. Two percent of volatile anesthetics, IBMX (3-isobutyl-1-methylxanthine, phosphodiesterase inhibitor) or L-NAME(Ng-nitro-L-arginine-methylester, Nitric oxide synthase inhibitor) was added and those contractile responses were observed respectively. We also measured nitric oxide synthase (NOS) activity of liver, lung and adrenal gland after 18 hours in the LPS-treated rats. Individual values between the control rats and LPS-treated rats were compared by unpaired t-test. A p-value less than 0.05 was considered statistically significant.

Contractile response of 2% halothane to norepinephrine was significantly decreased both in the control rats and LPS-treated rats. The NOS inhibitor enhanced the contractile responses to phenylephrine and norephinephrine in the vessels from LPS-treated rats more significantly than those of control rats.

These results suggest that LPS-treatment impairs vasopressor-induced contractility and doesn't alter the contractile responses during administration of volatile anesthetics.