Fig. 6

Summary of changes in placental monoamine uptake associated with trophoblast differentiation. Aims of the study were to characterize changes in monoamine transporter expression and function associated with trophoblast differentiation in vitro, and identify the optimal placental cell model for monoamine regulation studies. Isolated primary trophoblast cells from human term placenta (PHT) and the BeWo human choriocarcinoma cell line were used in the study. PHT cells differentiated spontaneously during a 72-h culture period, and BeWo cells’ differentiation was induced by incubation with 20 µM forskolin for 48 h. hCG transcripts in cells and hCG protein levels in their media were measured as molecular markers of trophoblast differentiation, and changes in both expression and function of monoamine transporters associated with the process were characterized. The results show that the process is accompanied by significant regulatory control of the transporters’ functionality and that cells derived from choriocarcinoma-derived lines, such as BeWo, may not be suitable models for studying placental monoamine transport due to both transcriptional and functional differences. Abbreviations: BM – basal membrane; CTB – cytotrophoblast; DA – dopamine; DAT – dopamine transporter; hCG – human chorionic gonadotropin; MVM – microvillous membrane; NE – norepinephrine; NET – norepinephrine transporter; OCT3 – organic cation transporter 3; PHT – primary trophoblast cells; SER – serotonin; SERT – serotonin transporter; STB – syncytiotrophoblast