For immunocytochemistry analysis, HEK 293 cells stably transfected with Dopamine D1 receptor (D1R) were grown on poly-L-lysine-coated coverslips overnight. Cells were then treated with 10 µM dopamine for 30 min, washed with PBS and fixed with 4% paraformaldehyde and 0.2% picric acid in phosphate buffer (pH 6.9) for 30 min at room temperature and washed several times with phosphate buffer. Specimens were permeabilized with ice-cold methanol and then incubated with Anti- DRD1 Recombinant Rabbit Monoclonal Antibody (Product # 702593, 1 µg/mL). Cells were then incubated with Goat anti-Rabbit IgG (H+L) Superclonal™ Secondary Antibody, Alexa Fluor® 488 conjugate for 2 h at room temperature, mounted and examined using a laser scanning confocal microscope. Note, robust receptor internalization after agonist exposure.

Sections of Rat brain striatum & hypothalamus were dewaxed, microwaved in citric acid and incubated with Anti-DRD1 Recombinant Rabbit Monoclonal Antibody (Product # 702593, 1 µg/mL, 1:500 dilution). Sections were then sequentially treated with biotinylated Anti-rabbit IgG and AB solution. Sections were further developed in AEC and lightly counterstained with hematoxylin. Panel a & b) shows the specific localization of DRD1 in neuronal stomata and dendrites in striatum and hypothalamus respectively. Panel c) shows the no primary antibody control.