Transplants in the peri- and intraventricular region grow better than those in the central parenchyma of the caudate.

The correlation between the growth of transplanted cells and behavior recovery in rats with lesions in the unilateral nigrostriatal dopamine (DA) pathway was investigated. Grafted cells in the lateral or third ventricle grew better than those in the caudate parenchyma. Immunocytochemical staining of tyrosine hydroxylase (TH) revealed that axons or dendrites of TH-like immunoreactive (TH-LI) cells transplanted periventricularly extended and ramified better than those of cells implanted in the central parenchyma of the caudate nucleus. The extent of ramification was well correlated with the recovery of behavioral imbalance. Data suggest that the growth and ramification of transplanted TH-LI cells are the most critical factors affecting behavior recovery, and this growth depends on the transplantation sites.