TABLE 4

Agonist and antagonist efficacies and potencies of selected agonists and antagonists in the IP accumulation using mouse A9 cells expressing human D2 receptors and CHO cells expressing human D3 receptors

Mouse A9 Cells*CHO-D3 Cells
AgonismAntagonismAgonismAntagonism
EmaxpEC50AAmaxpKbEmaxpEC50AAmaxpKb
Dopamine159 ± 166.95 ± 0.08N.T.N.T.102 ± 17.73 ± 0.01N.T.N.T.
Pramipexole130 ± 177.30 ± 0.11N.T.N.T.106 ± 38.65 ± 0.07N.T.N.T.
7-OH-DPAT145 ± 97.69 ± 0.17N.T.N.T.105 ± 48.50 ± 0.09N.T.N.T.
Quinpirole100 ± 37.01 ± 0.07N.T.N.T.101 ± 28.80 ± 0.02N.T.N.T.
Cariprazine30 ± 38.50 ± 0.3281 ± 39.22 ± 0.1871 ± 48.58 ± 0.3027 ± 29.57 ± 0.28
Aripiprazole34 ± 77.66 ± 0.3584 ± 48.52 ± 0.1269 ± 27.53 ± 0.0624 ± 37.80 ± 0.01
HaloperidolN.T.N.T.108 ± 410.47 ± 0.28N.T.N.T.110 ± 48.15 ± 0.03
SB-277011N.T.N.T.N.T.N.T.N.T.N.T.52 ± 67.56 ± 0.08
  • AAmax, percentage maximal antagonism achieved against (±)quinpirole in mouse A9 cells and maximal reversal of 100 nM 7-OH-DPAT-induced inhibition of 10 μM forskolin-induced cAMP accumulation in CHO-D3 cells, respectively. Shown are the means ± S.E.M. from three to six independent experiments in duplicate or triplicate. N.T., not tested.

  • * In these experiments (±)-quinpirole was used. Emax represents maximal stimulation relative to 1 μM (±)-quinpirole.

  • In these experiments (+)quinpirole was used. Emax represents the maximal inhibition of 10 μM forskolin-induced cAMP accumulation.