Failure of beta-blockers to modify the inhibitory dose-response curve to sodium nitrite in isolated rat aorta
Morcillo, E.; Bedate, H.; Esplugues, J.
Archivos de Farmacologia y Toxicologia 6(1): 11-16
1980
ISSN/ISBN: 0304-8616 PMID: 6104473 Document Number: 160531
A mechanism that may account for the postulated synergistic antianginal activity of nitrites and .beta.-blockers is not apparent, but a possible direct interaction at the vascular site of action of the nitrites must be considered. Modification by .beta.-adrenergic antagonists of the dose-response curve to sodium nitrite in the isolated rat aorta was examined. After a plateau level of muscle tone was achieved by KCl, 67 mM, or noradrenaline [norepinephrine, NA], 2 .mu.M, dose-response curves for sodium nitrite were obtained. Aorta strips taken from the same animal were incubated with propranolol (1 or 10 .mu.M) or pindolol (0.04 or 2 .mu.M), 15 min later contracted by KCl or NA and the dose-response curve to sodium nitrite recorded. No .beta.-blocker altered the dose-response curve to sodium nitrite when compared with the control group. Synergism between nitrites and .beta.-receptor antagonists is not based on a direct interaction at the level of the vascular smooth muscle.