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Endothelium modulation of the effects of nitroglycerin on blood vessels from dogs with pacing‐induced heart failure
Author(s) -
Forster Christine,
Main Jeffrey S.,
Armstrong Paul W.
Publication year - 1990
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1990.tb12098.x
Subject(s) - medicine , endothelium , cardiology , artery , coronary arteries , heart failure , acetylcholine , vein , blood vessel , coronary vessel , circumflex , anesthesia
1 The relaxant actions of nitroglycerin (previously considered to be an endothelium‐independent relaxing agent) and acetylcholine (an endothelium‐dependent relaxing agent) were compared on 4 vascular preparations (dorsal pedal artery, saphenous vein, left anterior descending coronary artery and circumflex coronary artery) from dogs with and without pacing‐induced congestive heart failure (CHF). 2 Responses of the coronary arteries to acetylcholine were unaltered in endothelium‐intact rings from dogs with and without heart failure. Similarly no such changes were observed in the peripheral vessels. The maximum relaxation produced by acetylcholine was always greater in the coronary vessels compared to the peripheral vessels. 3 Before heart failure, the coronary vessels were more sensitive and reactive to nitroglycerin compared to the peripheral vessels. 4 Removal of the endothelium in both the control (dogs without CHF) and experimental (dogs with CHF) rings enhanced the relaxant effects of nitroglycerin, such that the EC 50 for nitroglycerin became significantly lower in all denuded rings, with the exception of the saphenous vein and the left anterior descending coronary artery, before the development of CHF. 5 When CHF was maximally developed, vascular sensitivity to nitroglycerin was increased in peripheral vessels with an intact endothelium, but not in the coronary vessels. 6 These findings indicate that relaxation produced by nitroglycerin cannot be considered as entirely endothelium‐independent but should be considered endothelium‐modulated.