Ethanol suppresses L-arginine-induced relaxation response of rat aorta stimulated with bacterial lipopolysaccharide.
Using isolated rat aortic strips without endothelium, we investigated the effect of ethanol on L-arginine-induced relaxation. L-Arginine (10(-5)-10(-3) M) produced a relaxation response in vascular strips incubated for 6 hr with bacterial lipopolysaccharide (1 microgram/ml). The relaxation was either abolished by cycloheximide (10(-5) M) and actinomycin D (10(-5) M) or diminished by polymyxin B (10 micrograms/ml), dexamethasone (10(-5) M) and nitro-L-arginine (10(-4) M) under conditions in which these inhibitors were coincubated with lipopolysaccharide. Also, L-arginine-induced relaxation was significantly inhibited when ethanol (200, 400 mM) was present together with lipopolysaccharide during the 6-hr incubation. However, when ethanol was added to the organ bath after 6-hr incubation with lipopolysaccharide, it did not inhibit the relaxation. These results suggest that the relaxation response to L-arginine is mediated by an inducible type of nitric oxide synthase, which can be induced by lipopolysaccharide, and that ethanol may attenuate this nitric oxide-mediated relaxation by inhibiting expression of inducible nitric oxide synthase.
Hatake
K
K
Department of Legal Medicine, Nara Medical University, Japan.
Wakabayashi
I
I
D000818:Animals; D001011:Aorta / Q000187:drug effects; D001120:Arginine / Q000037:antagonists & inhibitors*; D003864:Depression, Chemical; D000431:Ethanol / Q000494:pharmacology*; D066298:In Vitro Techniques; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
D008070:Lipopolysaccharides; D009569:Nitric Oxide; D000431:Ethanol; D001120:Arginine; D019001:Nitric Oxide Synthase