Nitric oxide donor-induced inhibition of pregnant rat uterine spontaneous contractile activity and release of nitric oxide from uterus measured by microdialysis

T. Okawa, K. Asano, H. Takahashi, A. Sato, Y. P. Vedernikov, G. R. Saade, R. E. Gafield

Research output: Contribution to journalArticle


Our aim was to study whether nitric oxide (NO) donor-induced inhibition of pregnant rat myometrium contractility correlates with the release of NO. Uterine rings from mid-pregnant and late pregnant Sprague-Dawley rats were used for isometric tension recording. Concentration-response relationships to sodium nitroprusside (SNP), nitroglycerine (NTG) and diethylamine (DEA)/NO were assessed. The time course of NO release after addition to the organ chambers of the 3 NO-donors was assessed by the detection of NO products NOx (NO 3+NO2) using the microdialysis probe by a HPLC-NO detector system. DEA/NO induced greater inhibition of the spontaneous contractile activity of uterine rings from mid-pregnant rats than SNP or NTG. In uterine rings from late pregnant rats, however, the maximal inhibition of the contractility by all 3 NO-donors were significantly less. The NOx levels measured in the uterine ring walls from either mid-pregnant or late pregnant rats significantly increased after DEA/NO as compared to the basal levels or the levels after NTG or SNP. The decrease of NO-donor-induced inhibition of rat myometrium contractility, with unchanged formation of NOx, at term, suggests that the changes in NO signaling are responsible for gestational age-dependent attenuation of the inhibitory effect.

Original languageEnglish (US)
Pages (from-to)998-1002
Number of pages5
JournalJournal of Endocrinological Investigation
Issue number2
StatePublished - Jan 1 2005



  • Contractility
  • Microdialysis
  • NOx
  • Pregnancy
  • Uterus

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Endocrinology

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