Clinical significance of melatonin receptors in the human myometrium.

OBJECTIVE: To review and update the research on melatonin receptor expression in the human myometrium, in particular as it pertains to uterine contractility at labor. DESIGN: Summary of previous studies with the addition of new data on the transcriptional regulation of melatonin receptor expression in human myometrial cells. SETTING: Not applicable. PATIENT(S): Late-term pregnant volunteers. INTERVENTION(S): Biopsy collection for in vitro analyses provided the original data. More recently, uterine contractions in late-term pregnant volunteers were assessed before, during, and after acute white-light exposure. MAIN OUTCOME MEASURE(S): Melatonin receptor signaling in myometrial cells and uterine contractions in late-term pregnant volunteers. RESULT(S): Melatonin acts through the MTNR1B melatonin receptor that is expressed in the myometrium at late term to synergistically enhance oxytocin-dependent signaling and contractions. Acute inhibition of endogenous melatonin levels with light reversibly suppresses uterine contractions. CONCLUSION(S): These results point to a significant role for circulating melatonin in the timing and degree of uterine contractions in late-term pregnancy. Understanding the regulation of melatonin receptors remains a future objective.

The effect of thiola, piroxicam and diltiazem on the uterine contractility of gamma-irradiated rats.

Accidental radiation exposure raises concern for functional modifications in the uterine physiology. In the current work, total body gamma-irradiation (0.7, 1.4 and 2.1 Gy) of non-pregnant adult female albino rats increased significantly the frequency and amplitude of uterine contractions in vivo. Administration of Thiola (a sulfhydryl containing agent) in doses of 100 or 250 mg kg-1, pre-irradiation or Piroxicam (a potent prostaglandin inhibitor) in a dose of 2 mg kg-1, pre- or post-irradiation failed to normalize the changes induced by gamma-irradiation. However, administration of Diltiazem (a Ca2+ channel blocker, 8 mg kg-1) pre- or post-irradiation caused a significant decrease in the frequency of uterine contractions (21% and 24% respectively) in comparison to the uterotonic pattern of gamma-irradiation alone. The results indicate a promising tocolytic activity of Diltiazem against the uterotonic effect of gamma-radiation.

[Use of helium-neon laser irradiation in prenatal prevention of uterine inertia]. / Primenenie izlucheniia gelii-neonovogo lazera dlia dorodovoi profilaktiki slabosti rodovoi deiatel'nosti.

This paper reports results of clinical and experimental studies which sought to validate endonasal laser treatment for prevention of dysfunctional labor in late toxemia. Electrophysiologic and histochemical studies showed stimulating effects of the helium-neon laser treatment on function of large cell hypothalamic nuclei and uterine contractility. Clinical efficiency of this treatment was seen as a lower incidence of dysfunctional labor and cesarean section.