Fig. 7.

Midbrain graft. (A) Brightfield photograph of a representative unstained section showing the two nigral deposits identified in the right midbrain, at the border between the red nucleus and the rostral part of the SN. (B) Schematic representation of the stereological 3D reconstruction of the grafts in the right midbrain. At this level two parallel deposits were found between the red nucleus and the rostral SN, spanning 6.5 mm along the rostrocaudal axis. (C–F) TH immunostaining showed a typical disposition of transplanted neurons in the periphery of the graft. There were fewer TH neurons (Table 2) than in the striatal deposits and limited outgrowth. Higher magnification of three areas in this same deposit showing the small TH neurons within the graft where there is no lipofuscin (reddish deposits in the microphotograph). Arrows in D and E point to host neurons which are bigger and heavily melanized. (G–H) Confocal images of TH neurons in the graft. Some TH neurons coexpressed Girk2 and calbindin (colours as in Fig. 3) (Table 2). (I) Two dopamine subpopulations TH-positive/Girk2-positive (red) and TH-positive/Girk2-negative (green) were mapped in the mesencephalon of this patient at the level of the red nucleus (graft location), showing a high expression of Girk2 except in the midline populations. Around 50% of TH cells in the midbrain grafts coexpressed Girk2 (Table 2). In the mapped sections there was no preferential distribution of the TH/Girk2 (red) population in the margins of the deposits. Scale bar: C, 150 μm; D–H, 50 μm.