Comparison of VR binding and vanilloid-induced 45Ca2+uptake in sensory (DRG) neurons, mast cells, and glioma cells
| Neurons | Mast Cells | Glioma Cells | |
|---|---|---|---|
| Calcium influx | Yes | Yes | Yes |
| 45Ca2+ uptake by capsaicin (potency, nM) | |||
| Induction | 320 | 660 | 380 |
| Desensitization | 440 | 525 | 360 |
| Inhibition by capsazepine | 290 | 310 | 40 |
| Block by ruthenium red | 800 | 980 | 690 |
| 45Ca2+ uptake by resiniferatoxin (potency, nM) | |||
| Induction | 1.2 | 2.1 | 0.5 |
| Desensitization | 0.08 | 2.3 | 0.4 |
| Inhibition by capsazepine | 325 | 290 | N.D. |
| Block by ruthenium red | 790 | 910 | N.D. |
| [3H]RTX binding | Yes | No | No |
| Affinity (K d, nM) | 0.04 | N/A | N/A |
| Inhibition by capsaicin (K i, nM) | 4,900 | N/A | N/A |
| Inhibition by capsazepine (K i, nM) | 4,000 | N/A | N/A |
| Inhibition by ruthenium red (IC50, nM) | 14 | N/A | N/A |
N.D., not determined; N/A; not available. Data are from Ács et al., 1996b, 1997 (DRG neurons), Bı́ró et al., 1998a(mast cells) and b (glial cells), respectively.