Effect of intrastriatal 6-OHDA lesion on dopaminergic innervation of the rat cortex and globus pallidus.

The present study examined in the rat the effect of a partial lesion of the nigrostriatal dopaminergic pathway induced by intrastriatal injection of 6-hydroxydopamine (6-OHDA), on the dopaminergic innervation of the cortex and the globus pallidus as revealed using tyrosine hydroxylase (TH) immunoreactivity. Twenty-eight days after unilateral injection of 6-OHDA into the dorsal part of the striatum, TH-positive fiber density was reduced by 41% in the dorsal and central part of the structure, and was accompanied by a retrograde loss of 33% of TH-positive neurons in the substantia nigra (SN), while the ventral tegmental area was completely spared. In the SN, TH-positive cell loss was most severe in the ventral part of the structure (-55%).