AUTORADIOGRAPHIC LOCALIZATION OF D1 AND D2 DOPAMINE-RECEPTORS IN PRIMORDIAL STRIATAL TISSUE GRAFTS IN RATS

Using in vitro autoradiography the study examined the binding of the dopamine (DA) D1 receptor and D2 receptor radiolabelled ligands, [125I]SCH 23982 and [125I]sulpiride, respectively, to striatal sections of control rats, those with unilateral ibotenic acid (IA) lesions of the striatum and those with grafts of primordial striatal tissue implanted into the IA-lesioned striatum. In animals with IA-lesions, there was almost total degeneration of striatal neurones and a complete disappearance of both D1 and D2 receptors in the lesioned striatum. Within the striatal grafts, dense 'patches' of both D1 and D2 receptors were observed with densities comparable to those in the intact neostriatum. These data indicate that both D1 and D2 receptors are localized on the soma of intrinsic striatal neurones. Moreover, the specific localisation of D1 and D2 receptors in the grafts provides the neurochemical basis for the mechanisms by which the host nigrostriatal DA system can regulate the functional capacity of striatal grafts. © 1990.