Table 1.
Inhibition of elicitor-stimulated reactions in cultured parsley cells by anion channel blockers
| Inhibitor | IC50, μM
|
|||||
|---|---|---|---|---|---|---|
| Ca2+ influx | K+ efflux | Cl− efflux | H+ influx | H2O2 | Phytoalexins | |
| Anthracene-9-carboxylate | ||||||
| Anthracene-9-carboxylate | 15 | 24 | 16 | 87 | 39 | 4 |
| Anthracene-9-carbaldehyde | 7 | 40 | 55 | 87 | 20 | 10 |
| Anthraquinone-2-carboxylate | 15 | 17 | 12 | 31 | 15 | 3 |
| Xanthene-9-carboxylate | ND | 30 | 16 | 108 | 34 | 8 |
| 2-Aminoanthracene* | ND | — | — | — | — | — |
| Benzoic acid* | — | — | — | — | — | — |
| Diphenylamine-2-carboxylate | ||||||
| Niflumic acid | — | 3 | 7 | 19 | 15 | 11 |
| Flufenamic acid | — | 11 | 1 | 17 | 2 | 11 |
| Mefenamic acid | — | 11 | 4 | 78 | 6 | 12 |
| Tolfenamic acid | — | 3 | 3 | 33 | 11 | 5 |
| NPPB | — | 28 | 5 | 36 | 35 | 10 |
| NH2-NPPB* | ND | ND | ND | — | — | — |
| IAA-94 | — | 86 | 160 | 300 | 150 | 47 |
Concentrations required to inhibit the individual reactions by 50% (IC50) were determined by treating cells with the inhibitor 15 min before addition of crude cell wall elicitor (50 μg/ml) and measuring the indicated reactions 30 min (Ca2+, K+, Cl−, H+, H2O2) or 24 hr (phytoalexins) after initiation of elicitor treatment {ND, not determined; —, no effect; NPPB, 5-nitro-2-(3-phenylpropylamino)benzoate; NH2-NPPB, 5-nitro-2-[3-(4-aminophenyl)proylamino]benzoate; IAA-94, indanyloxyacetate 94; ∗, inactive derivative}.