Summary of potencies of (+)-Tc and 5-HT acting at mouse and human wild-type and chimeric 5-HT3A receptor subunits
| Receptor | (+)-Tc IC50 (mean ± S.E.) | n | 5-HT EC50 (mean ± S.E.) | nH |
|---|---|---|---|---|
| nM | μM | |||
| m5-HT3A wild type1-a | 1.40 ± 0.15 | 0.90 ± 0.10 | 2.30 ± 0.10 | 2.20 ± 0.20 |
| h5-HT3A wild type1-b | 2550.00 ± 150 | 1.00 ± 0.10 | 3.10 ± 0.10 | 1.94 ± 0.14 |
| m223h 5-HT3A | 1.16 ± 0.07 | 1.06 ± 0.07 | 2.56 ± 0.26 | 1.99 ± 0.22 |
| h218m 5-HT3A | 1870.00 ± 510 | 1.28 ± 0.09 | 2.84 ± 0.40 | 1.94 ± 0.08 |
| Mutant 1 | 27.50 ± 9.2 | 1.53 ± 0.15 | 4.66 ± 0.49 | 1.53 ± 0.07 |
| Mutant 2 | 486.00 ± 76 | 1.50 ± 0.09 | 1.70 ± 0.13 | 2.23 ± 0.18 |
| Mutant 3 | 76.00 ± 12.5 | 1.39 ± 0.18 | 5.84 ± 0.55 | 1.48 ± 0.09 |
| Mutant 4 | 99.50 ± 4.26 | 1.17 ± 0.17 | 1.44 ± 0.80 | 2.33 ± 0.33 |
| Mutant 5 | 228.00 ± 18 | 1.15 ± 0.15 | 4.79 ± 0.35 | 1.87 ± 0.04 |
| Mutant 6 | 49.40 ± 3.4 | 1.37 ± 0.27 | 2.24 ± 0.40 | 1.75 ± 0.46 |
IC50 values for (+)-Tc were calculated from a single-site model fitted to data as concentration of antagonist required to reduce inward current response evoked by 5-HT at EC50 by 50%.
Mutant 1, m5-HT3A I205M/D206E/I207S; mutant 2, h5-HT3A M200I/E201D/S202I; mutant 3, m5-HT3AQ199Y/K201R/I205M/D206E/I207S; mutant 4, h5-HT3AY194Q/R196K/M200I/E201D/S202I; mutant 5, m5-HT3AQ199Y/K201R/I205M/D206E/I207S/S210Y/I219V; mutant 6, h5-HT3AY194Q/R196K/M200I/E201D/S202I/Y205S/V214I.
↵1-a Data from Hope et al. (1993).
↵1-b Data from Belelli et al. (1995).