TABLE 1

Potency and maximal effects of the compounds tested for downstream effectors of the D2R

Data are an average of at least three individual experiments conducted in duplicate. For EC50 values, the 95% confidence interval is shown in parentheses. Maximal effects are shown as a percentage of dopamine’s maximal response, and S.E.M. is shown in parentheses. Potency ratios of β-arrestin recruitment/Gαi/o activation were also included.

Compoundβ-Arrestin 2 RecruitmentGαi/o ActivationGβγ ActivationPotency (EC50) Ratio
EC50Max Effect
(% Dopamine)EC50Max Effect
(% Dopamine)EC50Max Effect
(% Dopamine)β-Arrestin/Gαi/o
nMnMnM
Dopamine124 (100–153)100 (± 2)1.2 (0.7–2.1)100 (± 3)171 (72–407)100 (± 8)103
Quinpirole64 (59–70)96 (± 1)1.2 (0.9–1.6)100 (± 2)145 (89–236)103 (± 4)53
Lisuride0.4 (0.3–0.6)66 (± 2)0.07 (0.04–0.14)106 (± 5)2.2 (0.4–12.0)30 (± 6)9
Bromocriptine2.9 (1.9–4.4)101 (± 4)1.9 (0.9–4.3)104 (± 3)0.5 (0.1–2.1)34 (± 5)2
Aripiprazole3.6 (2.5–5.2)19 (± 1)1.3 (0.5–3.1)65 (± 4)ND−19 (± 5)3
Rotigotine0.2 (0.1–0.3)111 (± 4)0.02 (0.007–0.03)95 (± 3)1.5 (0.3–6.9)54 (± 9)10
(+)-3-PPP925 (809–1058)92 (± 1)8.6 (4.9–15.1)108 (± 4)518 (136–1973)57 (± 9)108
RNPA1.9 (1.5–2.5)101 (± 2)13 (3–57)95 (± 13)360 (210–619)110 (± 11)0.1
Pramipexole12 (10–15)94 (± 2)0.2 (0.1–0.3)108 (± 3)20 (9–46)86 (± 5)60
Ropinirole49 (37–63)92 (± 2)0.5 (0.3–0.8)111 (± 4)100 (34–290)56 (± 6)98
Pergolide7.2 (5.9–8.9)90 (± 2)0.04 (0.02–0.07)101 (± 4)2.3 (0.6–9.5)38 (± 7)180
  • ND, not determined.