Fetal substantia nigra grafts. Effect on dopamine receptors in the rat corpus striatium

Effects of fetal substantia nigra grafts on the dopamine receptors in the corpus striatum in rats were investigated after the destruction of the nigrostriatal dopaminergic pathways with intraventricular 6-hydroxydopamine injections. The expected dopamine receptor denervation supersensitivity was demonstrated by a 53.7% increase of [3H]spiroperidol binding in rats with sham grafts compared with normal control-group rats. In contrast, rats with grafts showed a significant reduction of supersensitivity, with a 25% decrease in binding to the graft-bearing caudate when compared with the sham-graft group. A nonsignificant 15% decrease in binding on the nongrafted side was also observed. The fetal substantia nigra grafts thus reduced the denervation supersensitivity toward a normal level.