Figure 8.

Roles of βarr2 on sucrose/agonist-induced desensitization of D₂R. A, Inhibition of β-arrestin expression by RNAi plasmids of β-arrestin1 [pcDNA3.1/Zeo(+)] and βarr2 [pcDNA3.0 (Neo)]. Stably transfected cells were selected, and the cellular β-arrestin was detected by immunoblotting using antibodies against β-arrestin1 or βarr2. B, Effects of sucrose treatment on the agonist-induced internalization of D₂R in control and βarr2 RNAi cells. Cells were treated as in Fig. 6A. C and D, Effects of knockdown of cellular βarr2 on agonist-induced desensitization of the WT-D₂R (C) and D₂R-IC2/3 (D). E and F, Effects of exogenous β-arrestin2 on agonist-induced desensitization of the WT-D₂R (E) and D₂R-IC2/3 (F) in βarr2 knockdown cells. *, P < 0.05; **, P < 0.01, ***, P < 0.001 when sucrose-DA group was compared with other experimental groups. #, P < 0.05; ##, P < 0.01 when vehicle-DA group was compared with vehicle-vehicle or sucrose-vehicle group. veh, Vehicle.