Endothelial control of vascular tone in large and small coronary arteries.
The endothelium modulates coronary vascular tone by the release of endothelium-derived relaxing or contracting substances. The endothelium-derived relaxing factor has been identified as nitric oxide synthesized in endothelial cells from L-arginine. The endothelium can release other relaxing substances such as prostacyclin and a hyperpolarizing factor. Endothelin-1 is a potent vasoconstrictor peptide formed by endothelial cells, and is likely to be the physiologic antagonist of endothelium-derived relaxing factor. Other putative contracting factors include superoxide anions and products of arachidonic acid metabolism. Endothelium-derived relaxing factor is released spontaneously and in response to flow, platelet-derived products (that is, serotonin, thrombin and adenosine diphosphate) and certain autacoids (that is, acetylcholine, bradykinin, histamine, substance P, vasopressin, alpha-adrenergic agonists). A considerable heterogeneity of responses exists among vessels of different size from different anatomic origin and different species. Hypercholesterolemia, atherosclerosis, hypertension and myocardial ischemia or reperfusion, or both, impair endothelium-dependent relaxation. Under normal conditions, endothelium-derived relaxing factor appears to dominate the control of vascular tone of large and small coronary vessels, whereas in disease states, endothelium-derived contracting factors are released. Impairments of endothelial function may be important in the development of various forms of cardiovascular disease.
Department of Medicine, University Hospital, Basel, Switzerland.
T F
TF
Lüscher
V
V
Richard
M
M
Tschudi
Z H
ZH
Yang
C
C
Boulanger
D000818:Animals; D003327:Coronary Disease / Q000503:physiopathology; D003331:Coronary Vessels / Q000502:physiology*; D016232:Endothelins; D004730:Endothelium, Vascular / Q000502:physiology; D006801:Humans; D010455:Peptides / Q000502:physiology; D014661:Vasoconstriction / Q000502:physiology; D014664:Vasodilation / Q000502:physiology
D016232:Endothelins; D010455:Peptides