Human Placental Chorionic Serotonin Receptor Subtypes And Functional Study

Human placenta is a unique organ that exchanges substance between fetal and maternal blood. It provides a number of functions to ensure that developing fetal is maintained in optimal conditions for the rapid events of gestation. Its various roles include nutritional and oxygen support by transfer from the maternal blood and metabolic waster product by remove from the fetal. Recently, many development biologists focus on this newly developing area. While initially considered solely for their role in the exchange of gas and nutrients and waster, however, actually this concept is limited and is going to be enlarging taking into account the other subjects, such as histology and embryology, biochemistry, molecular biology and immunology. A growing number of evidences that human placenta is able to produce bioactive substance. These substances play a role in the proliferation of trophoblast cell and induction secretion of placenta hormones. Now the human placenta is considered as endocrine organ that is a rich source of hormones ^ growth factors and cytokin et al.In this study, we use immunohistochemistry, electron microscope, cell culture, image analysis, MTT method and radioimmunoassay to study the localization, varies of quantitation, and possible frictions of 5-HT and subtype of 5-HTR in human placenta.The results were as follows:1. The syncytiotrophoblast and cytotrophoblast cell of human placenta showed 5-HTiA receptor and S-HTjreceptor immunoreactivity, positive substance was located in cytoplasm with negative nuclei.2. The relative amount of 5-HT)A receptor and 5-HT3 receptor varied withgestation ages and rose markedly with increasing week ages, During6th-9th week placneta, peaked at 9th-week,delined in 10th and terminal week age.3. By immunohistochemistry at electron microscopic level, the small flattened vesicles and large dense core vesicles in both laters of tropnoblast cells show 5 -HT] A receptor immunoreactivity in vesicle membrane and inclusion.4. 5-HTiA receptor and 5-HTs receptor immunoreactive material was distributed in cytoplasm of the human placenta trophoblast cell cultured, suggesting cultured human trophoblast cell may produce 5-HTiA receptor and 5-HTs receptor by itself.5. 5-HT at certain concentration, can markedly induce the hCG secretion of cultured trophoblast cells.6. 5-HT at certain concentration, can markedly stimulate proliferation of cultured trophoblast cells.