Substantia nigra lesion protects against ischemic damage in the striatum.

The role of striatal dopamine (DA) in mediating ischemic neuronal death was studied in the rat. Two weeks after unilateral substantia nigra lesion, rats were subjected to 20 min of forebrain ischemia by 4-vessel occlusion. Morphological changes and 45Ca uptake were evaluated after 3 days of survival. In the DA-depleted striatum, the degree of ischemic neuronal damage and 45Ca uptake were markedly attenuated compared to the contralateral side. This study is the first to demonstrate that the presence of DA is a prerequisite for the development of ischemic injury in the striatum and that DA depletion protects the striatum from ischemic damage.