Table 1.
Effect of linoleic acid and anandamide oxidative metabolites on various transient receptor potential channels
| TRPV1 | TRPM8 | TRPA1 | TRPV2 | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Efficacy (% ionomycin, 4 μM) | Potency (EC50, μM) | Efficacy of des. (% at max tested conc.) | Des. vs. Caps. (0.1 μM) (IC50, μM) | Efficacy of inhib. (% at max tested conc.) | Inh. icilin (0.25 μM) (IC50, μM) | Efficacy (% AITC, 100 μM) | Potency (EC50, μM) | Efficacy of des. (% at max tested conc.) | Des. versus AITC (100 μM) (IC50, μM) | Efficacy (% ionomycin 4 μM) | Potency (EC50, μM) | Efficacy of des. (% at max tested conc.) | Des. versus LPC (3 μM) (IC50, μM) | |
| 9(S)-HODE | 26.7 ± 1.0 | 21.0 ± 3.2 | 51.5 ± 1.5 | 86.2 ± 5.1 | 86.6 ± 2.5 | 43.6 ± 0.9 | 44.9 ± 1.8 | 31.9 ± 4.2 | 58.8 ± 0.6 | 43.6 ± 0.9 | <10 | NM | 40.8 ± 0.7 | >100 |
| 9(R)-HODE | <10 | NM | 29.0 ± 1.0 | >100 | 86.6 ± 1.5 | 55.7 ± 0.1 | ||||||||
| (+/-)13-HODE | 12.7 ± 0.5 | 27.5 ± 4.2 | 14.7 ± 0.5 | >100 | 79.8 ± 0.5 | 69.8 ± 3.6 | 40.0 ± 1.4 | 12.6 ± 2.2 | 61.6 ± 1.3 | 72.5 ± 0.8 | 12.5 ± 1.3 | 43.5 ± 1.6 | 47.4 ± 0.9 | >100 |
| 15(S)-HAEA | 72.9 ± 1.2 | 6.8 ± 0.4 | 100 | 6.3 ± 0.4 | ||||||||||
| Anandamide | 69.5 ± 1.6 | 0.28 ± 0.03 | 100 | 0.21 ± 0.01 | 100 | 0.15 ± 0.08 | 158.7 ± 11.1 | 10.1 ± 1.9 | 100 | 21.0 ± 1.6 | NM | NM | NM | NM |
| 9(S)-HODE(rTRPV1) | 13.9 ± 0.6 | 11.6 ± 3.0 | 38.6 ± 0.5 | >100 | ||||||||||
| 9(R)-HODE(rTRPV1) | <10 | NM | >100 | |||||||||||
Effect on TRPV1: The effect of the compounds on the elevation of intracellular calcium was measured by fluorescence as described in Methods, in HEK-293 cells stably over-expressing the human or the rat recombinant TRPV1 channel, and as a control, in wild-type HEK-293 cells. Efficacy was calculated as % of the effect obtained with ionomycin (4 μM). Capsaicin efficacy in this test is ∼75% of the effect of ionomycin. In the antagonism-desensitization experiments, the compounds were given to cells 5 min before capsaicin (0.1 μM), and data for the efficacy of desensitization (inhibition obtained at the maximum tested concentration) and potency of desensitization are provided. Data obtained for 9(S)- and 9(R)-HODE in HEK-293 cells overexpressing the rat recombinant TRPV1 (rTRPV1) are also shown in the last two lines of the Table. Data are means ± SD of n = 3 separate experiments. NM, not measurable.
Effect on TRPM8: The effect of the compounds and anandamide on the elevation of intracellular calcium was measured by fluorescence as described in Methods, in HEK-293 cells stably over-expressing the rat recombinant TRPM8 channel, and as a control, in wild-type HEK-293 cells. Data are means ± SD of n = 3 separate experiments in which various concentrations of the compounds were given to cells 5 min before icilin (0.25 μM). None of the compounds exerted any significant TRPM8-mediated effect on intracellular calcium per se (not shown).
Effect on TRPA1: The effect of the compounds on the elevation of intracellular calcium was measured by fluorescence as described in Methods, in HEK-293 cells stably over-expressing the rat recombinant TRPA1 channel, and as a control, in wild-type HEK-293 cells. Efficacy was calculated as % of the effect obtained with allyl isothiocyanate (AITC, 100 μM), the effect of which was ∼30% of that of ionomycin (4 μM). In the antagonism-desensitization experiments, the compounds were given to cells 5 min before AITC (100 μM), and data for the efficacy of desensitization (inhibition obtained at the maximum tested concentration) and potency of desensitization are provided. Data are means ± SD of n = 3 separate experiments.
Effect on TRPV2: The effect of the compounds on the elevation of intracellular calcium was measured by fluorescence as described in Methods, in HEK-293 cells stably over-expressing the rat recombinant TRPV2 channel, and as a control, in wild-type HEK-293 cells. Efficacy was calculated as % of the effect obtained with ionomycin (4 μM). In the antagonism-desensitization experiments, the compounds were given to cells 5 min prior to LPC (3 μM) and data for the efficacy of desensitization (inhibition obtained at the maximum tested concentration), and potency of desensitization are provided. NM, not measurable. Data are means ± SD of n = 3 separate experiments.