Knockdown of β-arr1 but not Dyn2 or Dyn1 prevents the ability of NT to reduce D2R function in cultured DA neurons. Patch clamp whole-cell recordings of cultured DA neurons transfected with siRNA molecules. A–D, examples of NT treatment protocols on recorded DA neurons transfected with Scr, β-arr1-, Dyn1-, or Dyn2-targeting siRNA molecules respectively. E, summary diagram showing the ability of NT to reduce Quin-induced firing rate inhibition. The black bars show the initial effect of Quin alone (Quin), whereas the gray bars show the effect of Quin after pretreatment with NT (Quin+NT). *, p < 0.05; **, p < 0.01; ***, p < 0.001; two-way ANOVA with Bonferroni multiple comparison tests (n = 5 for Scr, 7 for β-arr1, 5 for Dyn1, and 6 for Dyn2).