Although the role of melatonin on fetal development has been the subject of a number of studies, little is known about the function of melatonin in the placenta. We previously showed that melatonin receptors are expressed and are functional in JEG-3 and BeWo cell lines, both in vitro models of human trophoblast. Local synthesis of melatonin in placenta has been proposed, but the human placenta's ability to synthesize melatonin de novo has never been studied. The purpose of this study was to investigate the expression [reverse transcription-polymerase chain reaction (RT-PCR) and western blot analysis] and activity (radiometric assay) of melatonin synthesizing enzymes, and characterize the expression of the melatoninergic receptors in human term villous trophoblast. The results show that arylalkylamine N-acetyltransferase and hydroxyindole O-methyltransferase melatonin synthesizing enzymes are expressed and active in villous trophoblast as well as in JEG-3 and BeWo placental choriocarcinoma cells. In addition, immunohistochemical analysis demonstrated the presence of MT1, MT2, and retinoid-related orphan nuclear receptor alpha melatonin receptor proteins in both villous cytotrophoblast and syncytiotrophoblast (STB) as well as in endothelial cells surrounding the fetal capillaries and in the villous mesenchymal core. RT-PCR and western blot analysis in primary cultures of human term trophoblast confirmed the expression of all three melatonin receptors in villous cytotrophoblast and STB cells. This study demonstrates for the first time a local synthesis of melatonin and expression of its receptors in human trophoblasts and strongly suggests a paracrine, autocrine, and/or intracrine role for this indolamine in placental function and development as well as in protection from oxidative stress.

Human placental trophoblasts synthesize melatonin and express its receptors.

Purpose To explore relationships between fatigue, depression, stress, and infection in the postpartum. Study design and methods This was a cross-sectional, correlational design with a sample of 119 new mothers at 4 to 6 weeks postpartum. Mothers completed fatigue, mood, and stress instruments as well as maternal and infant infection checklists. Morning blood and hindmilk (in breastfeeders) samples were collected. ELISA was used to measure prolactin, cortisol, melatonin, and secretory IgA (sIgA). Correlations between psychosocial, health, and biologic variables were explored. Results Fatigue was correlated with symptoms of infection in both mothers and babies, with perceived stress and postpartum stress as well as with depression. Serum prolactin was inversely associated with depression. Milk sIgA was related to milk prolactin and inversely related to stress. Milk melatonin and prolactin were inversely related, and fatigue scores were correlated with melatonin and inversely with prolactin. Clinical implications The data suggest that fatigue, stress, depression, and infection are related in postpartum mothers and that these relationships extend to levels of serum hormones and milk factors. It is possible that a cycle is established that multiplies the effects of fatigue when mothers experience stress and that this cycle of stress and fatigue may lead to immune deficits and infectious illnesses.

Neuroendocrine and immune relationships in postpartum fatigue.

Lanoix D, Ouellette R, Vaillancourt C. Melatonin crosses the placenta and enters the fetal circulation. Moreover, experimental data suggest a possible influence of melatonin on placental function and fetal development in humans. To date, the expression and role of melatonin receptors in human placenta choriocarcinoma cell lines and in human term placental tissues remain to be elucidated. METHODS AND RESULTS : Results from RT-PCR, western blotting and confocal microscopy demonstrated that the (...)

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Expression of melatoninergic receptors in human placental choriocarcinoma cell lines

Physiological crosstalk between melatonin and glucocorticoid receptor modulates T-cell mediated immune responses in a wild tropical rodent, Funambulus pennanti.

En este trabajo evaluamos los aspectos morfologicos y cuantitativos de los sitios de implantaciones en uteros de ratas pinealectomizadas y/o sometidas a iluminacion constante. Los grupos experimentales fueron: I ­ ratas normales mantenidas en ciclo claro / oscuro de 12/12 horas, durante dos meses, cruzadas y sacrificadass en el 60 dia de prenez (control); II ­ ratas sham-pinealectomizadas mantenidas en ciclo claro/oscuro de 12/12 horas, durante dos meses, cruzadas y sacrificadas en el 60 dia de prenez (control); III ­ ratas pinealectomizadas mantenidas en ciclo claro/oscuro de 12/12 horas, durante dos meses, cruzadas y sacrificadas en el 60 dia de prenez; IV ­ ratas normales mantenidas en constante iluminacion durante dos meses acasaladas y sacrificadas en el 60 dia de prenez; V ­ ratas sham-pinealectomiazadas mantenidas en constante iluminacion durante dos meses, cruzadas y sacrificadas en el 60 dia de prenez; VI ­ ratas pinealectomizadas, mantenidas en constante iluminacion durante dos meses, cruzadas y sacrificadas en el 60 dia de prenez. El analisis estadistico de las medias de los sitios de implantaciones mostro que hubo diferencia significativa, donde los grupos III, IV, V y VI diferian de los grupos I y II, los cuales presentaron las mayores medias. Los grupos III, IV, V y VI no son diferentes entre si. El analisis morfologico de los sitios en los grupos controles revelo la presencia de pequenas lagunas conteniendo sangre, ademas de celulas trofoblasticas y algunos citrofoblastos poliploides. En los grupos III, IV, V y VI se evidencio lagunas muy desarrolladas en los sitios, con trofoblastos, citrofoblastos con alto grado de poliploidia y sinciciotrofoblastos. Concluimos que la pinealectomia y/o constante iluminacion llevan a una reduccion del numero de blastocistos implantados en ratas, ademas estimula el desarrollo de los sitios de implantacion, indicando asi; que la melatonina puede tener importante funcion en la viabilidad de implantacion del blastocisto

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Evaluation of the implantation in pinealectomized and/or submitted to the constant illumination rats

To date, the phenomenon of maternal transfer of hormones to the young is an enigma. The present study explains for the first time the maternal transfer of melatonin (MEL) to the young, affecting neona

K.S. Bishnupuri

Papers

Maternal transfer of melatonin alters the growth and sexual maturation of young Indian palm squirrel Funambulus pennanti.