GBR 12909 and 12935 block dopamine uptake into brain synaptic vesicles as well as nerve endings

GBR 12909 and 12935, commonly used as potent neuronal dopamine uptake blockers, also inhibit dopamine uptake into brain synaptic vesicles. The concentrations required for the latter activity (34-45 nM) are one order of magnitude higher than those required for inhibiting neuronal uptake of dopamine (1-6 nM). In contrast, the two activities differ by three orders of magnitude for cocaine (137 microM versus 0.35 microM). We propose that the vesicular effect of GBR-type dopamine uptake blockers should be taken into account when interpreting in vivo experiments.