Table 2.
Effects of K+ channel blockers on SCC following activation by forskolin in colonic epithelia
| Genotype | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Blocker | Concentration | Null | ΔF | Basal SCC (μA cm-2) | Amiloride ΔSCC (μA cm-2) | Forskolin (plateau) ΔSCC (μA cm-2) | 1st blocker ΔSCC (μA cm-2) | 2nd blocker ΔSCC (μA cm-2) | |
| Clofilium | 100 μM | WT | 2 | 1 | 38.8 ± 4.3 | −13.2 ± 0.9 | 130.5 ± 12 | 0 ± 0 | −85.2 ± 6.5 (Ba2+) |
| Clofilium | 100 μM | CF | 1 | — | 23.7 | −12.0 | −11.3 | 0 | 13.2 (Fr) |
| Charybdotoxin | 50 nM | WT | 3 | 1 | 54.5 ± 8.4 | −8.4 ± 3.2 | 143.2 ± 20.8 | −3.3 ± 3.3 | −106.2 (Ba2+) |
| Azimilide | 100 μM | WT | 2 | 1 | 31.7 ± 7.1 | −2.7 ± 1.4 | 175.2 ± 18.6 | −42.1 ± 21.1 | −114.1 ± 15.8 (293B) |
| Azimilide | 100 μM | CF | 1 | — | 10.7 | −13.6 | −33.7 | 0 | n.d. |
| TEA | 20 mM | WT | 2 | 1 | 22.4 ± 11.6 | −5.4 ± 2.2 | 174.7 ± 79.6 | −20.7 ± 27.8 | −85 ± 29.3 (Ba2+) |
The distribution of genotypes is indicated as for Table 1. The nature of the second blocker is indicated at the right-hand side of the table. Fr, furosemide. n.d., not determined.