Fig. 7.

Plots of the density of DAT-IR terminals (A–C) in the dorsal striatum against lesion size and the degree of regenerative sprouting (E–G).A, Density of DAT-IR terminals in WT mice is maintained until ∼75% SNpc neurons are lost, at which point density rapidly falls, presumably because remaining neurons can no longer compensate through sprouting. D shows WT animals degree of sprouting, 100% representing normal tree size and values >100% indicating a degree of sprouting. Note the significant degree of sprouting in WT animals when as few as 1500 (25%) of neurons remain.B shows density of DAT-IR terminals in IL-1R(−/−) mice with respect to varying lesion sizes. Note the persistent decline in density with increasing lesion size and the absence of sprouting in the remaining neurons in E. There was also a rapid decline in DAT density in IL-6(−/−) mice after lesioning (C) and very minimal sprouting in the remaining neurons (F). Note that each data point on the graphs represents one lesioned animal.