Effect of low dose L-NAME pretreatment on nitric oxide/reactive oxygen species balance and vasoactivity in L-NAME/salt-induced hypertensive rats

J Physiol Pharmacol. 2019 Aug;70(4). doi: 10.26402/jpp.2019.4.05. Epub 2019 Oct 19.

Abstract

Nicotinamide adenine dinucleotide phosphate hydrogen (NADPH) oxidase-dependent reactive oxygen species (ROS) overproduction and decreased nitric oxide (NO) bioavailability lead to vascular dysfunction and development of hypertension. The goal of our study was to analyze an effect of salt diet and NO synthase (NOS) inhibition with NG-nitro-L-arginine methyl ester (L-NAME) on blood pressure (BP), arterial reactivity, NO production, as well as ROS level in adult rats pretreated with low dose of L-NAME (2 mg/kg/day) for three weeks. Higher dose of L-NAME (40 mg/kg/day), or salt diet (8% NaCl), or combination of both were applied for the following four weeks. The administration of L-NAME in low dose had no effect on BP but enhanced the expression of eNOS. Both higher dose of L-NAME and salt diet elevated BP, decreased NOS activity, and impaired the endothelium-dependent arterial relaxation. However, salt diet did not increase ROS production and sympathoadrenergic arterial contractions in low dose L-NAME-pretreated rats. Combination of salt diet with higher dose of L-NAME did not evoke additive decrease of NOS activity, but it caused elevation of conjugated dienes (CD) concentration and NADPH oxidase 2 (Nox-2) protein expression. In conclusion, these findings indicate that chronic low dose of L-NAME treatment has a potential to trigger adapting mechanisms to attenuate some cardiovascular disorders.

MeSH terms

  • Animals
  • Heart Ventricles / drug effects
  • Heart Ventricles / metabolism
  • Hypertension / chemically induced
  • Hypertension / metabolism
  • Hypertension / physiopathology
  • Hypertension / prevention & control*
  • Kidney / drug effects
  • Kidney / metabolism
  • Male
  • Mesenteric Arteries / drug effects
  • Mesenteric Arteries / physiology
  • NADPH Oxidase 2 / metabolism
  • NG-Nitroarginine Methyl Ester / pharmacology*
  • Nitric Oxide / metabolism*
  • Nitric Oxide Synthase Type III / metabolism
  • Rats, Inbred WKY
  • Reactive Oxygen Species / metabolism*
  • Sodium Chloride, Dietary

Substances

  • Reactive Oxygen Species
  • Sodium Chloride, Dietary
  • Nitric Oxide
  • Nitric Oxide Synthase Type III
  • Nos3 protein, rat
  • Cybb protein, rat
  • NADPH Oxidase 2
  • NG-Nitroarginine Methyl Ester