Figure 6. Activation of Gβγ subunits reduces DAT activity in brain synaptosomes.

(A) mSIRK reduces [³H]-DA uptake in rat striatal synaptosomes. Samples were pre-incubated for 10 min with various concentrations of mSIRK (open circles) or scb-mSIRK (filled circles) at 34°C, followed by the addition of [³H]-DA (final concentration, 0.1 µM) for 8 min, n = 3. Nonspecific [³H]-DA uptake was determined in the presence of 10 µM nomifensine. (B) Kinetic analysis of the synaptosomal [³H]-DA uptake was determined in the absence (vehicle) or presence of 5 µM mSIRK, n = 3. **p<0.01.