To explore the possibility that embryonic stem (ES) cells to differentiate into tyrosine hydroxylase positive neurons in vitro. Murine embryonic stem cells cultured in ES medium containing leukemia inhibitory factor (LIF). and differentiated into tyrosine hydroxylase positive neurons through the following steps: generation of embryonic bodies (EBs), selection of nestin-positive cells, proliferation of nestin-positive cells in the presence of fibroblast growth factor 8(FGF8) and Sonic Hedgehog(SHH), and diff...