Adaptation to pregnancy leads to attenuated rat uterine artery smooth muscle sensitivity to oxytocin

Yuri P. Vedernikov, Ancizar Betancourt, Melissa J. Wentz, George R. Saade, Robert E. Garfield

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


Objective: We tested the hypothesis that oxytocin (OT) contracts blood vessels via vasopressin V1A (VP) receptors, and that this depends on pregnancy. Study design: Concentration-contraction relationships (CCR) to OT and VP (10-12-10-6 mol/L) were obtained in different blood vessels. CCR were obtained in uterine arteries (UA) from nonpregnant, mid-pregnant, and late pregnant rats (n = 6-10 per group) in the absence and presence of selective antagonists (10-7 mol/L). Results: Sensitivity to OT, but not to VP, is attenuated in pregnant rat UA. Antagonists shifted CCR of OT and VP to the right, and, to a lesser extent, of the counterpart, in all UA. VP antagonist depresses oxytocin CCR much more than OT antagonist in pregnant rat UA. Conclusion: OT and VP contract UA via their own receptors, although partial cross-activation is evident. Adaptation to pregnancy led to attenuated sensitivity of UA smooth muscle to OT and transformed OT receptors into VP-like ones.

Original languageEnglish (US)
Pages (from-to)252-260
Number of pages9
JournalAmerican journal of obstetrics and gynecology
Issue number1
StatePublished - Jan 2006


  • Oxytocin
  • Receptors
  • Uterine artery
  • Vascular adaptation to pregnancy
  • Vasopressin

ASJC Scopus subject areas

  • Obstetrics and Gynecology


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