extracellular Ba2+, indicating activation of GIRK channels (Figure 4A). In VTA DA neurons of SNX27DA KO mice, however, the GTPγS-induced Ba2+-sensitive currents were significantly reduced (Figure 4B). On average, the GTPγS-stimulated currents were ~75% smaller in SNX27DA KO mice (161.0 ± 21.7, n=13 for WT; 117.9 ± 7.5, n=11 for Dat-Cre+/−; 33.2 ± 5.7, n=8 for SNX27DA KO, p < 0.05), similar to the reduction in IBaclofen. These results suggest SNX27 is important for regulating surface expression of GIRK channels coupled to GABAB receptors in DA neurons.
