Vascular smooth muscle-derived relaxing factor (MDRF) and its close similarity to nitric oxide.
The principal finding in this study is that vascular smooth muscle generates a labile relaxing factor that possesses pharmacological and chemical properties that are similar to those of authentic nitric oxide. MDRF was generated by perfusion of endothelium-denuded bovine pulmonary artery as assessed by bioassay. In addition, endothelium-denuded arterial rings that were incubated at 37 degrees C for 24 hr to lower endogenous L-arginine levels relaxed in response to L-arginine but not D-arginine. Freshly mounted, endothelium-denuded arterial rings were not relaxed by L-arginine but did relax in response to the dipeptide L-arginyl-L-alanine. Relaxant responses were accompanied by increases in smooth muscle levels of cyclic GMP and nitrite, and were inhibited by oxyhemoglobin, methylene blue, and NG-nitro-L-arginine. NG-Nitro-L-arginine also caused endothelium-independent contractile responses. Thus, a relaxing factor with the properties of nitric oxide can be generated from vascular smooth muscle.
Wood
K S
KS
Department of Pharmacology, UCLA School of Medicine 90024.
Buga
G M
GM
Byrns
R E
RE
Ignarro
L J
LJ
D000818:Animals; D001681:Biological Assay; D002417:Cattle; D006152:Cyclic GMP / Q000378:metabolism; D009126:Muscle Relaxation / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism* / Q000494:pharmacology; D009573:Nitrites / Q000032:analysis
D009573:Nitrites; D009569:Nitric Oxide; D006152:Cyclic GMP