Table 4.
Efficacy and potency of pure cannabinoids as functional agonists at TRPV2 channels, and their potency as desensitizers of TRPV2 to the effect of lysophosphatidylcholine (LPC)
| Cannabinoid | Efficacy (% ionomycin 4 µM) | Potency shown as EC50 (µM) | Desensitization (% LPC 3 µM) IC50 (µM) |
|---|---|---|---|
| CBC | <10 | ND | 6.5 ± 1.6 |
| CBD | 40.5 ± 1.6 | 1.25 ± 0.23 | 4.5 ± 0.7 |
| CBG | 73.6 ± 1.2 | 1.72 ± 0.08 | 1.5 ± 0.2 |
| CBN | 39.9 ± 2.1 | 19.0 ± 3.7 | 15.7 ± 2.1 |
| CBDA | <10 | ND | 114.0 ± 18.0 |
| CBGA | <10 | ND | 87.3 ± 1.2 |
| CBDV | 49.9 ± 0.9 | 7.3 ± 0.4 | 31.1 ± 0.2 |
| CBGV | 75.4 ± 2.4 | 1.41 ± 0.36 | 0.7 ± 0.06 |
| THC | 53.0 ± 1.4 | 0.65 ± 0.05 | 0.8 ± 0.1 |
| THCA | 68.2 ± 1.0 | 18.4 ± 0.9 | 9.8 ± 2.6 |
| THCV | 73.8 ± 1.0 | 4.11 ± 0.11 | 0.8 ± 0.5 |
| THCVA | <10 | ND | 104.3 ± 9.9 |
| LPC | 91.71 ± 0.47 | 3.37 ± 0.025 | NT |
The effect of the compounds on the elevation of intracellular calcium was measured by fluorescence as described in Methods and was assessed in HEK-293 cells stably overexpressing the rat recombinant TRPV2 channel, and as a control, in wild-type HEK-293 cells. Data are means ± SEM of at least n = 3 separate experiments in which various concentrations (1, 10, 100, 1000, 10 000 and 25 000 nM) of the pure compounds were given to cells. Efficacy was calculated as % of the effect obtained with ionomycin (4 µM). In the antagonism-desensitization experiments, the same concentrations of the pure compounds were given to cells 5 min prior to LPC (3 µM).
CBC, cannabichromene; CBD, cannabidiol; CBDA, cannabidiol acid; CBDV, propyl analogue of CBD or cannabidivarin; CBG, cannabigerol; CBGV, cannabigivarin; CBN, cannabinol; THC, Δ9-tetrahydrocannabinol; THCA, THC acid; THCV, propyl analogue of THC or tetrahydrocannabivarin; THCVA, tetrahydrocannabivarin acid; ND, not determined; NT, not tested.