Vitamin C lowers blood pressure and alters vascular responsiveness in salt-induced hypertension

Can J Physiol Pharmacol. 2002 Dec;80(12):1199-202. doi: 10.1139/y02-147.

Abstract

The present study was undertaken to investigate the effect of vitamin C treatment on blood pressure and vascular reactivity in salt-induced hypertension. Male Sprague-Dawley rats were fed a normal rat diet, a high-sodium (8% NaCl) diet, a normal rat diet plus vitamin C treament (100 mg x kg(-1) x day(-1)), or a high-sodium diet plus vitamin C treatment for 6 weeks. Salt loading significantly increased blood pressure, which was attenuated by vitamin C treatment. Aortic rings from the different groups were suspended for isometric-tension recording. The contractile response to noradrenaline was significantly increased in the salt-loaded rats. Vitamin C reduced the sensitivity of aortic rings to noradrenaline in rats on normal and high-sodium diets. In noradrenaline-precontracted rings, the relaxation response to acetylcholine, which was attenuated in the salt-loaded rats, was restored by vitamin C treatment. Pretreatment with N(G)-nitro-L-arginine methyl ester (L-NAME) abolished the enhanced response to acetylcholine caused by vitamin C. The results suggest that the antihypertensive effect of vitamin C is associated with a reduction in vascular sensitivity to noradrenaline and enhancement of endothelium-dependent relaxation due to increased nitric oxide bioavailability.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Ascorbic Acid / pharmacology*
  • Ascorbic Acid / therapeutic use*
  • Blood Pressure / drug effects*
  • Blood Pressure / physiology
  • Dose-Response Relationship, Drug
  • Hypertension / chemically induced
  • Hypertension / drug therapy*
  • Hypertension / physiopathology*
  • In Vitro Techniques
  • Male
  • Rats
  • Rats, Sprague-Dawley
  • Sodium Chloride, Dietary / toxicity
  • Vasoconstriction / drug effects
  • Vasoconstriction / physiology
  • Vasodilation / drug effects*
  • Vasodilation / physiology

Substances

  • Sodium Chloride, Dietary
  • Ascorbic Acid