Histological analysis of 6-OHDA lesioned rats. Tyrosine hydroxylase (TH) immunohistochemistry reveals loss of TH staining in the striatum of the lesioned hemisphere following striatal lesion using 10 μg (A) or 20 μg (B) 6-0HDA or following 6-OHDA lesioning of the medial forebrain bundle (C). (D) Cavalieri quantification of the proportion of TH immunoreactivity retained in the caudate putamen for the separate 6-OHDA experimental groups, as well as the sham group. Data are shown as mean ± s.e.m. Scale bar, 1 mm.