Table 1.
Binding affinities (pKi) for a range of 5-HT4 ligands at native 5-HT4 receptors in guinea-pig striatal membranes and recombinant guinea-pig 5-HT4 and human 5-HT4(b) receptors stably expressed in HEK293 cells
| Compound | gp 5-HT4/HEK293 | gp striatal membranes | h 5-HT4(b)/HEK293 |
|---|---|---|---|
| pKi | pKi | pKi | |
| (mean±s.d.) | (mean±s.d.) | (mean±s.d.) | |
| GR113808 | 10.3±0.2 | 10.4±0.1 | 10.5±0.1 |
| RS39604 | 10.1±0.5 | 9.8±0.1 | 10.1±0.1 |
| SB203186 | 9.9±0.2 | 9.3±0.2 | 9.4±0.1 |
| RS67506 | 9.4±0.1 | 8.9±0.1 | 9.0±0.1 |
| RS67333 | 8.7±0.1 | 8.7±0.1 | 9.0±0.1 |
| RS23597–190 | 8.6±0.1 | 8.3±0.1 | ND |
| Tegaserod | 8.4±0.2 | 7.7±0.3 | 8.1±0.1 |
| TS951 | 8.1±0.1 | 7.5±0.2 | 7.6±0.1 |
| Prucalopride | ND | 7.7±0.1 | 7.5±0.1 |
| Cisapride | 7.7±0.1 | 7.4±0.2 | 7.4±0.1 |
| BIMU-8 | 7.6±0.2 | 6.9±0.2 | 7.2±0.1 |
| Mosapride | 7.4±0.2 | 7.0±0.1 | 7.2±0.1 |
| 5-HT | 7.4±0.2 | 7.2±0.2 | 6.9±0.2 |
| RS56812 | 7.2±0.1 | 6.7±0.2 | 7.1±0.1 |
| 5-MeOT | 6.9±0.1 | 6.4±0.1 | 6.4±0.1 |
| Metoclopramide | 6.7±0.2 | 6.3±0.4 | 6.7±0.1 |
Abbreviations: 5-HT, 5-hydroxytryptamine; 5-MeOT, 5-methoxytryptamine; ND, not determined.
Competition binding experiments were as described in the Methods section. Data are given as the mean±s.d. from at least three independent experiments.