Effect of nitric oxide on contractions of uterine and cervical tissues from pregnant rats

T. Okawa, Y. P. Vedernikov, G. R. Saade, R. E. Garfield

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

Our objective was to evaluate the role of the nitric oxide (NO)-cyclic guanosine monophosphate (cGMP) pathway in rat uterine and cervical contractility at mid- and late gestation. Rings of uterus and cervix from Sprague Dawley rats on day 14 of pregnancy (mid-) and day 21 of pregnancy (late) were equilibrated at 2 g passive tension in organ chambers filled with Krebs-Henseleit solution and bubbled with 5% CO2 in air (37°C, pH approximately 7.4). Rings were treated with an inhibitor of outward potassium current, tetraethylammonium, to activate phasic contractions, and the concentration-response relationships to diethylamine/NO and 8-bromo-cGMP (8-br-cGMP) were assessed. Baseline spontaneous activity was significantly higher at term gestation in both uterine and cervical rings compared with mid-gestation. Spontaneous contractile activity was not apparent in cervical rings from rats in mid-gestation, but was persistent after treatment with tetraethylammonium. Oxyhemoglobin did not affect NO-induced inhibition of activation by tetraethylammonium contractile activity in either cervical or uterine tissues in mid- or late gestation. The 8-br-cGMP concentration- dependently inhibited tetraethylammonium-activated contractions that were more pronounced in uterine tissues compared with cervical tissues in both mid- and late gestation. We concluded that activation of the NO-cGMP pathway inhibits both uterine and cervical smooth muscle contractility. Both tissues demonstrated refractoriness to NO at term.

Original languageEnglish (US)
Pages (from-to)186-193
Number of pages8
JournalGynecological Endocrinology
Volume18
Issue number4
DOIs
StatePublished - Apr 1 2004

Keywords

  • Cervix
  • Contraction
  • Nitric Oxide
  • Pregnancy
  • Uterus

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Endocrinology
  • Obstetrics and Gynecology

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