Effects of chronic increased salt intake on nitric oxide synthesis inhibition-induced hypertension

J Hypertens. 1995 Jan;13(1):123-8.


Objective and method: Experimental evidence suggests that endogenous nitric oxide plays an important role in the homeostatic response to an increase in sodium intake. In the present study we evaluated the influence of a high sodium intake (1% NaCl as drinking water) on arterial hypertension induced by long-term (6-7 weeks) inhibition of nitric oxide synthesis [NG-nitro-L-arginine methyl ester (L-NAME), 75 mg/100 ml in the drinking fluid] in rats.

Results: Treatment with L-NAME induced progressive elevations in tail-cuff systolic blood pressure, but there were no differences between rats drinking tap water and rats drinking 1% NaCl. Direct measurement of blood pressure at the end of the treatment confirmed the hypertension and the lack of differences between the two groups treated with L-NAME. Metabolic studies performed at the end of L-NAME treatment showed a reduced glomerular filtration rate and elevated urinary excretion of immunoreactive endothelin in the two hypertensive groups treated with L-NAME. Drinking intake, diuresis and natriuresis were significantly higher only in the L-NAME group drinking 1% NaCl. Both groups treated with L-NAME showed an accelerated and increased diuretic and natriuretic response to an isotonic 0.9% NaCl load (2.5 ml/100 g body weight, intraperitoneally). At the end of the study ventricular hypertrophy was observed in both L-NAME groups.

Conclusion: The present results indicate that the time-dependent elevation in blood pressure produced by long-term inhibition of nitric oxide production is not affected by an increased sodium intake. However, salt supplementation induced the development of a polyuria and polydipsia syndrome in rats treated with L-NAME. The elevated excretion of endothelin in both groups treated with L-NAME suggests the possible participation of endothelin in the development of L-NAME hypertension.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Arginine / analogs & derivatives
  • Body Weight / drug effects
  • Diet
  • Diuresis
  • Drinking
  • Endothelins / urine
  • Glomerular Filtration Rate
  • Hypertension / chemically induced
  • Hypertension / metabolism*
  • Kidney / drug effects
  • Kidney / metabolism
  • Male
  • NG-Nitroarginine Methyl Ester
  • Nitric Oxide / antagonists & inhibitors
  • Nitric Oxide / biosynthesis*
  • Rats
  • Rats, Wistar
  • Sodium Chloride, Dietary / administration & dosage*


  • Endothelins
  • Sodium Chloride, Dietary
  • Nitric Oxide
  • Arginine
  • NG-Nitroarginine Methyl Ester