Fig. 6. Schematic
representation of D1 and D2 receptor localization on the rat nigro- striatal system.
D2 receptors appear to be located presynaptically on glutamatergic fibers of the corticostriatial
pathway. (b), D2 receptors are located presynaptically on the DA-ergic fibers of the nigrostriatial
pathway. (c), both D1 and D2 receptors are located on the cell bodies of the nigrostriatial
pathway (SNC).(e), the vast majority of D1 receptors of the SNR are located
presynaptically on the GABA-ergic fibers of the striatonigral pathway.