Synthesis of oxytocin in amnion, chorion, and decidua may influence the timing of human parturition.

Abstract

Despite the widespread clinical use of oxytocin (OT) as a potent and specific stimulant of labor, previous research data have not supported a role for OT in the physiology of normal human parturition. We have demonstrated synthesis of OT mRNA in amnion, chorion, and decidua using Northern blot analysis, ribonuclease protection assays, and in situ hybridization. Probes directed towards both the 3' and 5' ends of the gene have been used. Levels were highest in decidua with considerably less in chorion and amnion and very low levels in placenta. The transcript size in decidua appears to be 60-80 nucleotides smaller than the transcripts in amnion and chorion. OT gene expression in chorio-decidual tissues increased three-to fourfold around the time of labor onset. Estradiol stimulated synthesis of OT mRNA during in vitro incubation. These results support the hypothesis of a paracrine system involving OT and sex steroids within intrauterine tissues wherein significant changes could occur without being reflected in the maternal circulation. Such a paracrine system could rationalize a long-sought role for oxytocin in the physiology of human labor. These data may lead to novel approaches towards prevention or treatment of preterm labor. (J. Clin. Invest. 1993. 91:185-192.)

Advances in the role of oxytocin receptors in human parturition

“…Interestingly, significantly greater concentrations of OT mRNA were detected in the chorio-decidua after spontaneous onset of labour (at the expulsive stage of parturition) compared to before the onset of labour at term [27][28][29]. Post labour chorio-decidua samples showed similar levels of OT mRNA to that of spontaneous labour, indicating the maximal level of gene expression.…”

“…In 1993, mRNA of OT was isolated in human uterine tissues in late gestation [27]. A semi-quantification analysis revealed that OT mRNA is principally localised/or identified in decidua but also found in the chorion and amnion.…”

A New Maneuver for Prevention of Postpartum Haemorrhage

“…This positive feedback continues till expulsion and stops after delivery of the baby in the process of normal labor. In addition, these uterine contractions are reinforced as Oxytocine stimulates prostaglandin production by the uterine lining [11,12].…”

Molecular cloning, pharmacological characterization, and histochemical distribution of frog vasotocin and mesotocin receptors

“…At the periphery, AVP regulates water excretion, vascular tone, and adrenocorticotropin (ACTH) secretion (De Rouffignac et al 1991, de Keyzer et al 1996, Szczepanska-Sadowska 1996 while OT stimulates milk ejection and enhances uterine contractility during parturition (Chibbar et al 1993, Nishimori et al 1996. In the central nervous system, AVP is involved in thermoregulation, learning and memory processes, social recognition, and aggressive behavior (de Wied et al 1993, Alescio-Lautier & Soumireu-Mourat 1998, Rose & Moore 2002) while OT plays a crucial role in sexual activity and induces maternal behavior (Pedersen & Prange 1979, Ivell et al 1997.…”