In the September 1st online edition of Stem Cells, J. P. Weick et al. from the University of Wisconsin published their study results on how influx of calcium (Ca++) ions modulates neuronal development in human embryonic stem cells. The investigators noted that "telencephalic human neuroepithelia (hNE) and post-mitotic neurons (PMNs) generated from embryonic stem cells display robust Ca++ transients." Data from drug-treated cells and knockdown experiments suggest that transient influx of Ca++ is modulated by transient receptor potential channels (TrpCs). Inhibition of transient Ca++ in dividing hNEs results in a reduction in proliferation. Additionally, the researchers found that inhibition of TrpC expression reduces neurite formation in PMNs. The authors concluded that "Trp channels present a novel mechanism for controlling Ca++ transients in human neurons and may offer a target for regulating proliferation and neurite outgrowth when engineering cells for therapeutic transplantation."