L-ARGININE INDUCES RELAXATION OF SMALL MESENTERIC-ARTERIES FROM ENDOTOXIN-TREATED RATS

The effect of arginine (Arg) was studied on norepinephrine- (1-mu-M) precontracted small mesenteric arteries removed from rats treated with E. coli lipopolysaccharide (LPS). The addition of L- (but not D-) Arg (1 mM) relaxed, within 3 min, the small mesenteric arteries from LPS-treated but not from control rats, the maximal relaxation (65.3 +/- 11%) being reached with less than 100-mu-M L-Arg. N(G)-Nitro-L-arginine methyl ester (1 mM) and methylene blue (10-mu-M) restored contractions to the level reached before addition of L-Arg. These results show that LPS induces the production of an L-Arg-derived, nitric oxide-like, relaxing factor in small mesenteric arteries.