Endothelium, coronary vasodilation, and organic nitrates.
Recent investigations have suggested that the vascular endothelium is an active participant in the regulation of arterial tone and blood flow. In a state of health, the endothelium contributes to hemodynamic equilibrium; however, it rapidly becomes dysfunctional in hypercholesterolemia and diabetes mellitus or with exposure to the stress of hypertension or long-term smoking. Among the deficits observed during endothelial dysfunction is a reduction in the synthesis and release or an excessive degradation of EDRF. This potent vasorelaxant is derived from the amino acid L-arginine and has been characterized as NO or a closely related substance. EDRF relaxes vascular smooth muscle by activating guanylate cyclase. A deficiency in the activity of EDRF may be the mechanism of diminished coronary vasodilation in patients with ischemic heart disease. Organic nitrates, which are metabolized to NO or S-nitrosothiol at the cellular level, are often used in the management of myocardial ischemia; they also induce vasodilation by activating guanylate cyclase. The similarities between organic nitrates and endogenous EDRF and their interactions are discussed in this review.
Division of Cardiovascular Medicine, University of Florida, Gainesville 32610-0277.
J L
JL
Mehta
D003331:Coronary Vessels / Q000187:drug effects / Q000502:physiology*; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D017202:Myocardial Ischemia / Q000188:drug therapy / Q000503:physiopathology; D009566:Nitrates / Q000627:therapeutic use*; D009569:Nitric Oxide / Q000502:physiology; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology*
D009566:Nitrates; D009569:Nitric Oxide