Abstract
Morphological and electrophysiological analyses were carried out to investigate the fate of neuroepithelial stem cells grafted in the striatum. The neuroepithelial stem cells were harvested from the mesencephalic neural plate of transgenic GFP-carrying rat embryos, and stereotaxically implanted into the striatum of normal adult rats. 4-6 weeks after the implantation, grafted neuroepithelial stem cells differentiated mostly into neurons together with some astrocytes. Some donor-derived neurons stained positively for tyrosine hydroxylase (TH), but no donor-derived neurons stained positively for dopamine- and cAMP-regulated phosphoprotein, Mr 32 kDa (DARPP-32). However, 6 months after the grafting, DARPP-32-positive neurons could be observed. Action potentials and both glutamatergic and GABAergic spontaneous postsynaptic currents were recorded with whole-cell recording from donor-derived neurons in the striatal slices 4-6 weeks after the implantation. Furthermore, both glutamatergic and GABAergic postsynaptic currents were evoked by the electrical stimulation applied to the host area. These results suggest that grafted neuroepithelial stem cells differentiate to functionally active neurons in the host brain tissues and make synaptic contacts to the environment, indicating their feasibility in the functional repair of damaged neural circuitry. [Jpn J Physiol 54 Suppl:S155 (2004)]
