Short term hypercholesterolemia alters N-G-nitro-L-arginine- and indomethacin-resistant endothelium-dependent relaxation by acetylcholine in rabbit renal artery

The tension of isolated rings was measured isometrically to compare the N-G -nitro-L-arginine- and indomethacin-resistant relaxation by acetylcholine ( ACh) in the renal artery from normal rabbits and short term hypercholestero lemia rabbits (0.5% cholesterol chow for 5 weeks). ACh-induced relaxation i n the renal artery precontracted with phenylephrine was not influenced by c holesterol-enriched chow. However, in comparison with artery from normal ra bbits, the N-G-nitro-L-arginine- and indomethacin-resistant endothelium-dep endent relaxation by ACh was significantly enhanced by the chow. The resist ant part of ACh-induced relaxation was significantly inhibited when the art ery was treated with tetraethylammonium or SKF 525a. Results suggest that s hort term hypercholesterolemia modulates endothelium-derived hyperpolarizin g factor-mediated relaxation in rabbit renal artery.