Figure 6.

SN and VTA DA neuron numbers in CBLG-DT and control mice after the first phase of natural cell death and in adulthood. A, At PNDs 7–9, at the nadir of cell death after the first phase, there is a 46% increase in the total number of SN DA neurons in double transgenic (DT) animals (n = 14) compared with WT controls (n = 16; **p < 0.001, ANOVA). There was also an increase in comparison with CaMKII-tTA monotransgenic (MT) controls (n = 8). For this analysis, CBLG-DT mice were always analyzed in parallel with littermate controls. B, Representative SN DA neurons at PND 7 revealing a typical example of the size difference between DA neurons in WT and DT animals. Neurons have been immunoperoxidase stained for TH. Scale bar, 10 μm. C, In adult animals, there was no longer a difference between double-transgenic and wild-type animals in the total number of SN DA neurons (n = 8, both groups). D, In adult animals, there was a 55% increase in the number of VTA DA neurons in double-transgenic animals compared with wild-type controls. The sections used for this analysis were the same as those used for the SN analysis shown in C.