Endothelium-dependent and -independent vasodilation involving cyclic GMP: relaxation induced by nitric oxide, carbon monoxide and light.
The characteristics of carbon monoxide (CO)-induced, endothelium-independent relaxation of rabbit aorta were compared with those of nitric oxide (NO)-induced and light-induced relaxation and endothelium-dependent relaxation mediated by endothelium-dependent relaxing factor (EDRF). CO was less than one thousandth as potent as NO as a relaxant. Various findings, including an increase in cyclic GMP associated with CO-induced relaxation, led to the conclusion that CO - like NO, EDRF and light - produces relaxation as a result of its stimulation of guanylate cyclase. LY 83583, which generates superoxide, was a potent, fast-acting inhibitor of acetylcholine-induced endothelium-dependent relaxation and NO-induced relaxation, and a fairly potent, moderately fast-acting inhibitor of photorelaxation, but only a very weak inhibitor of CO-induced relaxation. The ability of LY 83583 as well as hemoglobin to inhibit photorelaxation is consistent with the hypothesis that on radiation a photo-induced relaxing factor is formed which can stimulate guanylate cyclase and which can be inactivated by superoxide and by hemoglobin.
Furchgott
R F
RF
Department of Pharmacology, SUNY Health Science Center, Brooklyn.
Jothianandan
D
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D000634:Aminoquinolines / Q000494:pharmacology; D000818:Animals; D001013:Aorta, Thoracic; D002248:Carbon Monoxide / Q000494:pharmacology*; D006152:Cyclic GMP / Q000502:physiology*; D004730:Endothelium, Vascular / Q000502:physiology*; D008027:Light; D009569:Nitric Oxide / Q000494:pharmacology*; D011817:Rabbits; D014664:Vasodilation / Q000187:drug effects* / Q000528:radiation effects
D000634:Aminoquinolines; D009569:Nitric Oxide; D002248:Carbon Monoxide; C041715:6-anilino-5,8-quinolinedione; D006152:Cyclic GMP