title: Dilation of coronary artery stenosis: a major mechanism of the effect of nitrates.
abstract: The mechanisms of action of nitroglycerin have been studied extensively; but despite this, there is controversy regarding the manner in which this commonly used drug exerts its dramatic beneficial effect. Angina is usually due to inadequate subendocardial perfusion. Improvement in subendocardial ischemia is achieved not by one single mechanism, but by three contributory phenomena. First, nitroglycerin directly dilates most coronary stenoses, with an average 40% reduction in resistance to flow through severely narrowed arterial segments. Second, the drug decreases left ventricular "afterload" and thus reduces the myocardial oxygen demand by an average of 10%. Third, the drug decreases ventricular diastolic filling pressure (preload) an average of 30%, and thereby improves the distribution of coronary blood to the subendocardial zone.
mesh_terms: D003327:Coronary Disease / Q000188:drug therapy* / Q000503:physiopathology; D006801:Humans; D005996:Nitroglycerin / Q000494:pharmacology* / Q000627:therapeutic use; D010477:Perfusion; D005082:Physical Exertion; D014664:Vasodilation / Q000187:drug effects
chemical_list: D005996:Nitroglycerin