PMID: 9557281Apr 29, 1998Paper

Randomized, double-blind, placebo-controlled study of supplemental vitamin E on attenuation of the development of nitrate tolerance

Journal of cardiology
H WatanabeY Sugishita

Abstract

The attenuation of intracellular production of cyclic guanosine monophosphate (cGMP) has been known as a mechanism of nitrate tolerance. A recent in vitro study have shown an increase in superoxide levels and a reduced activation of guanylate cyclase in tolerant vessels. We investigated the preventive effect of an antioxidant, vitamin E, on the development of nitrate tolerance. In this double-blind, placebo-controlled study, 24 normal volunteers and 24 patients with ischemic heart disease (IHD patients) were randomized to receive either vitamin E (200 mg t. i. d.; vitamin E group) or placebo (placebo group). Vasodilator response to nitroglycerin was assessed with forearm plethysmography by measuring the change in the forearm blood flow before and 5 min after sublingual administration of 0.3 mg nitroglycerin, and at the same time, blood samples were taken from veins to measure the platelet cGMP level. Measurements of the forearm blood flow and blood sampling were obtained serially at baseline (day 0), 3 days after taking vitamin E or placebo alone (day 3), and 3 days after application of a 10 mg/24 hr nitroglycerin tape concomitantly with oral vitamin E or placebo (day 6). The response of forearm blood flow (%FBF) and cGMP (%cGM...Continue Reading

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