Binding affinities for [125I]RTX binding to membranes from native rat VR1 and recombinant rodent VR1
| Rat spinal cord Ki | HEK293/VR1Ki | |
|---|---|---|
| nM | ||
| Agonists | ||
| RTX | 0.36 ± 0.07 | 0.31 ± 0.06 |
| Capsaicin | 1995 ± 360 | 2030 ± 270 |
| Olvanil | 202 ± 35 | 397 ± 80 |
| Antagonists | ||
| Capsazepine | 7880 ± 1570 | 2150 ± 850 |
| Ruthenium red | >30.000 | >30.000 |
| I-RTX | 4.8 ± 0.6 | 5.8 ± 1.1 |
IC50 values were calculated from competition binding experiments by a nonlinear regression analysis fitted to an one-site model using the GraphPad Prism program (GraphPad Software, San Diego, CA) and converted to K i values using the equationK i = IC50/(1 +[L]/K d), where [L] is the concentration of radioligand (0.2 nM).