Elevated plasma nitrate levels in depressive states

J Affect Disord. 2001 Mar;63(1-3):221-4. doi: 10.1016/s0165-0327(00)00164-6.


Background: Previous studies have shown that nitric oxide (NO) synthase inhibitors show preclinical antidepressant-like properties, suggesting that NO is involved in the pathogenesis of depression. The purpose of this study is to examine whether or not NO production increases in depressed patients.

Methods: Plasma nitrate concentrations, an index of NO production, were measured by high-performance liquid chromatography in depressed patients (n=17) and compared with patients suffering anxiety (n=6) and with healthy controls (n=12).

Results: Plasma nitrate concentrations were significantly higher in depressed patients than in patients with an anxiety disorder (P<0.05) or in controls (P<0.01).

Limitations: The study group was small. The source of the surplus production of NO in patients with major depressive episode remains unclear.

Conclusions: These results suggest that NO production is increased in depression.

Publication types

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

MeSH terms

  • Adult
  • Anxiety Disorders / physiopathology*
  • Biomarkers / analysis
  • Depression / physiopathology*
  • Female
  • Humans
  • Male
  • Nitrates / blood*
  • Nitrates / metabolism
  • Nitric Oxide / biosynthesis*
  • Nitric Oxide / blood


  • Biomarkers
  • Nitrates
  • Nitric Oxide