[3H]Dopamine Uptake in Rat Striatal Synaptosomes.

Synaptosomes were resuspended in KRB as described above, aliquoted into 13- × 100-mm borosilicate glass test tubes, and incubated with tamoxifen or vehicle for 60 minutes at 37°C. Cocaine (100 μM) was used to measure nonspecific [³H]dopamine uptake. Unlabeled dopamine (20–300 nM) supplemented with 10 nM [³H]dopamine was added to the synaptosomes. The reaction was stopped at 3 minutes for saturation experiments and 30 seconds for kinetic experiments by the addition of 3 ml cold KRB followed by filtration through glass fiber filters (GF/C; Fisher Scientific) and washed twice more with cold KRB. Filters were dried and transferred to scintillation vials, and radioactivity was counted in 5 ml ScintiVerse cocktail (Thermo Fisher Scientific, Waltham, MA) using a Beckman LS5801 scintillation counter (Beckman Coulter, Brea, CA).