Intrastriatal grafts of fetal ventral mesencephalic tissue restore quantitative and qualitative D1/D2 dopamine receptor synergism in the striatum

Grafts of fetal ventral mesencephalic (VM) tissue into the striatum of unilaterally 6-hydroxydopamine lesioned rats reduce many of the behavioural and neural changes associated with the lesion. In this report, the ability of such grafts to restore the qualitative and quantitative synergistic relationship between Dl-like and D2-like receptors in the striatum was investigated. In animals with a unilateral 6-hydroxydopamine lesion of the nigrostriatal bundle, there was a loss of qualitative and quantitative DA receptor coupling in the striatum, consistent with previous reports. Intrastriatal fetal VM grafts restored both qualitative and quantitative DA receptor synergism to the same level as was observed in the intact striatum. Thus, the ability of intrastriatal grafts to ameliorate some behavioural deficits observed after unilateral lesion may be due to the recoupling of DA D1/D2 synergisms within the striatum.