The Relaxant Effect of Nitroglycerin on Oxytocin Desensitized Human Myometrium
Status:
Completed
Trial end date:
2018-04-13
Target enrollment:
Participant gender:
Summary
Oxytocin causes myometrial contraction via the oxytocin receptor (OTR). Desensitization of
the OTR after exposure to oxytocin has been demonstrated in previous studies. The resultant
need for a higher oxytocin dose to cause adequate uterine contraction in vivo has also been
demonstrated in laboring women having received oxytocin for labor augmentation.
Achieving rapid uterine relaxation can be invaluable for maternal and fetal wellbeing in some
acute obstetric emergency settings. Nitroglycerin has become a commonly used agent for
achieving rapid uterine relaxation amongst obstetric anesthesiologists.
Previous studies have concluded that oxytocin can be used to re-establish uterine tone
following nitroglycerin mediated relaxation. However, no studies to date have looked at the
effects of nitroglycerin mediated relaxation of uterine muscle that has undergone oxytocin
receptor desensitization. Nor has the response to oxytocin re-exposure and return of
contractility in desensitized myometrium (following nitroglycerin) been examined.
The investigators hypothesize that nitroglycerin will reduce and inhibit uterine contractions
in both oxytocin pre-treated myometrium, as well as untreated myometrium in a dose dependent
fashion, but that myometrium that has undergone OTR desensitization will require less
nitroglycerin for contractions to abate.
The investigators also expect that the dose of oxytocin required to re-establish equivalent
contractions will be higher in the myometrial samples which have undergone nitroglycerin
mediated relaxation.
Phase:
N/A
Details
Lead Sponsor:
Samuel Lunenfeld Research Institute, Mount Sinai Hospital