RESUMEN
BACKGROUND: Endotoxins play important roles in the pathophysiologic alterations associated with sepsis so the authors examined the effects of hydroxocobalamin, NW-nitro-L-arginine-metyl ester (L-NAME) and aminoguanidine on thiopental-induced contractile responses of lipopolysaccharide (LPS)-treated and control rat aortic rings. METHODS: Aortic ring preparation was obtained from LPS-treated (1.5mg/kg, i.p. for 18h) rats. Cumulative doses of thiopental (10-4~3x10- 3M) were added to construct contraction response curves. Hydroxocobalamin (10-5M), L-NAME (10-6M) or aminoguanidine (10-6M) were added as NO scavenger or as NOS inhibitors. Contraction curves by cumulative doses of thiopental (10-4~3x10-3M) were remeasured after treatment of NO scavenger or NOS inhibitors. Statistical significances (p<00.05) were analyzed according to data characteristics by Student's t-test, paired t-test or ANOVA. RESULTS: The vascular responses of cumulative thiopental (10-4~3x10 3M) administration were dose- dependent contraction and LPS-treated rat was less contracted (p<00.05). There was significant increment on vascular contraction induced by thiopental after hydroxocobalamin pretreatment in LPS-treated rat (p<0.05), in spite of L-NAME, aminoguanidine pretreatment was failed to increase contractile forces in control and LPS-treated rats. CONCLUSIONS: From these results, viewed from maintenance of vasomotor tone in septic state, it is suggested that hydroxocobalamin may be candidate for vasopressor during usual induction of general anesthesia.