Analysis of [3H]spiperone binding sites in the rat striatum and frontoparietal cortex by means of quantitative receptor autoradiography after inactivation of dopamine receptors by N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline in vivo: selective protection by sulpiride in the striatum.

By means of quantitative receptor autoradiography in combination with inactivation of dopamine (DA) receptors by N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ), it was demonstrated in the male rat that [3H]spiperone predominantly labels D2 receptors in the striatum, nucleus accumbens and tuberculum olfactorium, and predominantly non-DA receptors in the frontoparietal cortex, probably mainly serotonin type 2 (5-HT2) receptors in layer IV. Furthermore, the [3H]spiperone-labelled D2 receptors found all over the dorsal and ventral striatum appear to be similarly inactivated by EEDQ and protected by the D2 antagonist (+/-) sulpiride but not the D1 antagonist SCH 23390, indicating a homogeneity of the striatal D2 receptors.