Fig. 4.
Antagonist activity of haloperidol, clozapine, and aripiprazole on Gi/o activation and β-arrestin 2 recruitment induced by quinpirole. (A) Dose-response curve for haloperidol, clozapine and aripiprazole (Upper, Middle, and Bottom Left) for inhibiting adenylylcyclase inhibition induced by quinpirole. HEK 293 cells stably coexpressing EPAC biosensor and D2LR were treated with the different antipsychotics and quinpirole (1 μM) in the presence of forskolin (25 μM). (B) Dose-response curve for haloperidol (Upper Right), clozapine and aripiprazole (Middle and Bottom Right, respectively) for inhibiting β-arrestin 2 recruitment induced by 1 μM of quinpirole. BRET was measured in cells coexpressing Rluc-tagged D2LR and YFP-tagged β-arrestin 2. Data represent the mean ± SEM of 3–5 independent experiments each performed in duplicate.