INDUCTION OF NITRIC-OXIDE SYNTHASE BY LIPOTEICHOIC ACID FROM STAPHYLOCOCCUS-AUREUS IN VASCULAR SMOOTH-MUSCLE CELLS

Inducible vascular nitric oxide synthase accounts for the contractile impairment observed in endotoxemia. We provide evidence that lipoteichoic acid (LTA) from Staphylococcus aureus, a micro-organism without endotoxin, also induces nitric oxide synthase. Our study demonstrates that on endothelium-free rings of rat aorta, LTA-like lipopolysaccharide induces a loss of contractility restored by Methylene blue and N(G)-nitro-L-arginine-methyl ester (LNAME). Moreover in cultured vascular smooth muscle cells, LTA produces a dose-dependent increase in intracellular cyclic GMP which is antagonized by LNAME and prevented by dexamethasone. which is antagonized by LNAME and prevented by dexamethasone.