Concentration-dependent actions of EEDQ on receptor density and function in CHO-hD3 membranes
| EEDQ | Receptor Saturation | [35S]GTPγS Bound | |
|---|---|---|---|
| KD | Bmax | ||
| μM | nM | % of control | % of control |
| 0 | 1.18 ± 0.19 | 100 | 100 |
| 10 | 1.38 ± 0.01 | 71.5 ± 9.3 | 77.5 ± 8.7 |
| 33 | 1.31 ± 0.03 | 47.7 ± 7.6 | 51.2 ± 1.6 |
| 100 | 1.24 ± 0.11 | 32.0 ± 4.7 | 44.9 ± 2.0 |
| 300 | 1.33 ± 0.09 | 18.7 ± 6.4 | 33.6 ± 5.6 |
CHO-hD3 cell membranes were treated with different concentrations of EEDQ. Receptor density was determined in [125I]iodosulpiride saturation binding experiments. Percentage of remaining hD3 binding sites is calculated as a percentage of mean Bmax determined in absence of EEDQ (15.43 pmol/mg, Table 1). [35S]GTPγS binding is expressed as percentage of dopamine (10 μM)-dependent binding observed under control conditions in parallel experiments.