Receptor Binding Density Quantification

The receptor binding density for D1 and D2 receptors was adapted from the protocols described in Sommer et al. (31 (link)) and Behuet et al.’s study (32 (link)). The tritiated ligands [³H]-SCH23390 and [³H]-Raclopride were purchased from PerkinElmer (Germany). SCH23390 is a potent D1 and D5 receptor antagonist. Raclopride is a D2 and D3 selective receptor antagonist. Both ligands bind to the receptors localized on the cell surface, without penetrating inside the cell membrane. In the first step, the pre-incubation, endogenous ligands were washed off. In the following main incubation, the tritiated ligands were incubated both in the presence of a competitor, in order to determine the unspecific binding, and without it, in order to assess the total binding. Finally, the slices were rinsed. The slices incubated with [³H]-Raclopride were additionally dried with a cold air stream. A detailed description of the protocols used is reported in Table 1.