Inhibition of forskolin-stimulated cAMP production of dopamine D2 receptors
| EC50 (nM) | Maximum Inhibition (%) | |||
|---|---|---|---|---|
| Dopamine | 6,7-ADTN | Dopamine | 6,7-ADTN | |
| A7-D2 | 3.09 ± 0.46 (3) | 0.28 ± 0.06 (5) | 78.83 ± 2.73 (3) | 79.68 ± 4.31 (5) |
| M2-D2 | 33.78 ± 1.08 (4)3-150 | 4.90 ± 0.73 (3)3-150 | 42.03 ± 5.19 (4)3-150 | 33.79 ± 3.65 (3)3-150 |
| CHO-D2 | 3.17 ± 0.50 (3) | ND | 86.70 ± 0.57 (3) | ND |
D2 receptors were stably expressed in M2, A7, and CHO cells. All were stimulated with 10 μM forskolin and increasing concentrations of dopamine or 6,7-ADTN. The EC50 values (nM) and the maximum inhibition levels (%) were calculated from the dose-response curves of cAMP production. Data shown are the mean ± S.E. from three to five experiments, indicated in parentheses. D2 receptor expression levels were 2.48 pmol/mg of protein (M2) versus 2.55 pmol/mg of protein (A7). The stable CHO cell clone used contained receptor levels of 1.07 pmol/mg of protein.
↵3-150 P < .05, compared with A7-D2or CHO-D2 cells, unpaired Student's t test.
ND, not determined.