Fig. 5.

Model of RGS9’s role in regulation of striatal D₂Rs to promote proper motor control. RGS9 inhibits D₂R signaling in striatal indirect MSNs (iMSNs) promoting neuronal activity/excitability to regulate motor function. By inhibiting striatal iMSN D₂R-Gα_i/o signaling, RGS9 suppresses βγ-mediated GIRK channel activation, promoting depolarization and neuronal firing. This figure depicts SNc DA neurons (blue) synapsing on GABAergic D₂R-containing iMSNs (red). Gα_i/o-coupled receptors are red. MSN, medium spiny neuron.