Modulation of iNOS activity in age-related cardiac dysfunction

Bo Yang, Douglas F. Larson, Ronald R. Watson

Research output: Contribution to journalArticlepeer-review

40 Scopus citations


Based on the role of inducible nitric oxide synthase (iNOS) in heart failure, we hypothesized that the elevated expression of iNOS compared to young mice in the myocardium contributes to the age-related decline of left ventricular (LV) function. Cardiac iNOS mRNA and protein expression was singularly identified in old, wild type (WT) male mice (I6-month) and not in young WT male mice (6-month). Characterized with in vivo pressure-volume loops analysis, an age-related LV dysfunction was found in the old WT mice. The LV dysfunction of the aged mice was modified to that of the younger mice by the specific iNOS inhibitors, aminoguanidine (AMG, 10 mg/Kg, i.v. or infusion, n = 15) and S-methyl-isothiourea (MITU, 3 mg/Kg, i.v. n = 7), and declined with L-arginine (10 mg/Kg, i.v. n = 7). All three drugs had no effects on the LV function of young WT mice or old iNOS knockout (KO) mice. The NOx and cGMP levels were significantly higher only in the old WT mice (n = 6) and cGMP levels decreased to normal with AMG administration. In conclusion, these results suggested that the iNOS/NO/cGMP pathway may contribute to ventricular dysfunction during the aging process and that inhibition of iNOS activity significantly improved heart function in aged mice.

Original languageEnglish (US)
Pages (from-to)655-667
Number of pages13
JournalLife Sciences
Issue number6
StatePublished - Jun 25 2004


  • Aging
  • Conductance catheter
  • Nitric oxide synthase
  • Ventricular function

ASJC Scopus subject areas

  • General Pharmacology, Toxicology and Pharmaceutics
  • General Biochemistry, Genetics and Molecular Biology


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