Binding affinities of CCK and gastrin to wild-type and CCK-B ICL-1 mutant receptors in the presence and absence of GTPγS
| Receptor | CCK-8 | Gastrin-17 | ||
|---|---|---|---|---|
| Control | +GTPγS | Control | +GTPγS | |
| IC50 , nM | ||||
| CCK-BR WT | 0.46 ± 0.13 | 1.1 ± 0.32-150 | 1.3 ± 0.4 | 5.2 ± 0.8** |
| CCK-B(G80→I) | 0.36 ± 0.11 | 0.6 ± 0.2 | 2.2 ± 0.3 | 5.5 ± 1.22-150 |
| CCK-B(L81→R) | 4.1 ± 0.3 | 4.3 ± 1.1 | 11.6 ± 1.7 | 38.2 ± 7.4** |
| CCK-B(S82→N) | 0.8 ± 0.2 | 2.7 ± 0.82-150 | 10.1 ± 1.4 | 56.1 ± 10.3** |
| CCK-B(L85→M) | 1.2 ± 0.4 | 2.3 ± 1.0 | 12.4 ± 1.8 | 22.8 ± 5.62-150 |
| CCK-AR WT | NB | NB | NB | NB |
CCK-BR selective antagonist [3H]PD 140386 was used as radioligand to perform saturation binding assays on cell membranes in the absence (control) and presence of 10 μM GTPγS. IC50 in nM was calculated from competitive binding curve of each receptors. Values are mean ± S.E. from three separate experiments.
↵2-150 P < .05; ** P < .001 versus control. NB, no binding.