Morphological changes in immunopositive cells of ionotropic glutamate receptor subunits during the development of transplanted fetal ventral mesencephalic neurons.

To elucidate the morphological changes in immunopositive cells of ionotropic glutamate receptors within intrastriatal 'developing' grafts of fetal ventral mesencephalon (VM) in 6-hydroxydopamine-lesioned rats, immunohistochemistry was performed to detect cells expressing N-methyl-D-aspartate (NMDA) receptor subunit 1 (NR1), the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptor subunits (GluR1, GluR2/3, and GluR4), or tyrosine hydroxylase (TH) in the intrastriatal VM grafts at 1, 4, and 12 weeks following transplantation. One week after transplantation, TH-positive cells were detected without any immunoreactivity of the NMDA and AMPA receptor subunits in the grafts. Four weeks after transplantation, TH-positive cells, distributed homogeneously in the grafts, appeared to be multipolar and larger compared to those at 1 week post-grafting.