Reproductive sciences
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Reproductive sciences · Sep 2012
The A118G single-nucleotide polymorphism of human μ-opioid receptor gene and use of labor analgesia.
The human µ-opioid receptor (MOR) is the major site of action of endogenous opioids and most of the clinically used opioid analgesics. The single-nucleotide polymorphism (SNP), A118G of the MOR 1 gene (OPRM1), has been associated with altered pain perception. The aim of this study was to investigate whether this polymorphism of OPRM1 is associated with a number of pain-related behaviors during labor. ⋯ A plasma sample was collected from each participant and an SNP genotyping assay was performed. No differences in sociodemographic variables or labor pain-related outcomes, such as stage of cervical dilation on arrival at the delivery unit or use of any type of second-line analgesia during spontaneous labor, were found between noncarriers and G-allele carriers of OPRM1. We conclude that there is no association between the A118G polymorphism of OPRM1 regarding pain-related behavior during labor.
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Reproductive sciences · Sep 2012
Contractile efficacy of various prostaglandins in pregnant rat myometrium pretreated with oxytocin.
Oxytocin pretreatment of pregnant rat myometrium has been shown to reduce the contractions produced by further administration of oxytocin, as a function of the desensitization phenomenon. It is unclear whether this phenomenon affects the contractions produced by various prostaglandins that are used in the management of postpartum hemorrhage. The objective of this study was to investigate the contractile effects of various prostaglandins after oxytocin pretreatment and to compare their relative efficacies in vitro on pregnant rat myometrial strips. ⋯ However, there was a significant decrease in the frequency (P = .02) and motility index (P = .05) in the dose-response curves of oxytocin in the groups pretreated with oxytocin compared with the control groups. Overall, oxytocin produced superior contractions compared with all other prostaglandins, while dinoprostone and misoprostol produced the weakest contractions. The uterotonic effects of various prostaglandins are not affected by oxytocin desensitization; and despite desensitization, oxytocin provides superior contractions compared with the prostaglandins.