Kainate lesion dissociates striatal dopamine receptor radioligand binding sites

Kainic acid lesion of rat striata reduces the specific dopamine receptor binding of the butyrophenone antagonist [3H]spiperone and the butyrophenone-like antagonist [3H]domperidone by 56% and 59% respectively. Significantly greater decreases in binding were observed with the agonist [3H]N-propylnorapomorphine (NPA) and the antagonist [3H]flupentixol which showed 79% and 73% losses of high affinity binding respectively. These data indicate that, in part, [3H]spiperone and [3H]domperidone label distinct dopamine receptors with different neuronal localizations from those labeled by [3H]flupentixol and [3H]NPA. Our data is consistent with the hypothesis that [3H]flupentixol and [3H]NPA bind preferentially to adenylate cyclase-linked dopamine (D1) receptors.