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.
Mehta
J L
JL
Division of Cardiovascular Medicine, University of Florida, Gainesville 32610-0277.
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