title: Smoking a single cigarette rapidly reduces combined concentrations of nitrate and nitrite and concentrations of antioxidants in plasma.
abstract: BACKGROUND
  Cigarette smoking is a well-known risk factor for the development of cardiovascular disease, yet the mechanism of action involved is not completely understood. Because cigarette smoke contains superoxide and other reactive oxygen species, it has been hypothesized that some of the adverse effects of smoking may result from oxidative damage to endothelial cells, which results in nitric oxide (NO) shortage. However, little information is available regarding the acute effects of smoking on plasma concentrations of NO and antioxidants. We measured the changes in the combined plasma concentrations of nitrate and nitrite as an index of NO concentration, as well as changes in concentrations of major serum antioxidants (ascorbic acid, cysteine, methionine, and uric acid) in smokers after smoking a single cigarette.
  
  
  RESULTS
  A randomized crossover study of the effects of smoking a single cigarette was performed in 20 smokers. Smoking a sham cigarette induced no significant changes in all assayed parameters. However, smoking a single cigarette significantly decreased nitrate and nitrite plasma concentrations by 3.5 +/-1.2 and 3.4 +/- 1.1 micromol/L, compared with plasma concentrations at presmoking and sham smoking, respectively. The concentrations of ascorbic acid and other antioxidants were also significantly lower after smoking a single cigarette. These parameters returned to preexperimental levels 60 minutes after smoking cessation.
  
  
  CONCLUSIONS
  The present findings indicate that smoking a single cigarette temporarily decreases nitrate, nitrite, and serum antioxidant concentrations in the plasma. These transient changes may partially contribute to coronary vasoconstriction, which is routinely observed after smoking.
authors.affiliation: Department of Biochemistry and Molecular Pathology, Osaka City University Medical School, Abenoku, Osaka, Japan. oxymasa@ea.mbn.or.jp
authors.forename: Masahiko
authors.initials: M
authors.lastname: Tsuchiya
authors.forename: Akira
authors.initials: A
authors.lastname: Asada
authors.forename: Emiko
authors.initials: E
authors.lastname: Kasahara
authors.forename: Eisuke F
authors.initials: EF
authors.lastname: Sato
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Shindo
authors.forename: Masayasu
authors.initials: M
authors.lastname: Inoue
mesh_terms: D000328:Adult; D000975:Antioxidants / Q000032:analysis*; D001205:Ascorbic Acid / Q000097:blood; D018592:Cross-Over Studies; D003545:Cysteine / Q000097:blood; D006801:Humans; D008715:Methionine / Q000097:blood; D009566:Nitrates / Q000097:blood*; D009573:Nitrites / Q000097:blood*; D012907:Smoking / Q000009:adverse effects* / Q000097:blood*; D013997:Time Factors; D014527:Uric Acid / Q000097:blood
chemical_list: D000975:Antioxidants; D009566:Nitrates; D009573:Nitrites; D014527:Uric Acid; D008715:Methionine; D003545:Cysteine; D001205:Ascorbic Acid