Author(s): Furchgott RF, Jothianandan D
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Abstract 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.
This article was published in Blood Vessels
and referenced in Journal of Clinical & Experimental Cardiology