Effect of L-type Ca2+ channel blockers, modulators of Mdr1, and inhibitors of K+ channels on ZG K+ and Cl−conductances
| Drug | Concentration | K+ conductance | Cl−conductance |
|---|---|---|---|
| M | % Difference | ||
| (±)-BZDC-DHP | 10−5 | −41.7 ± 7.3 | −6.2 ± 7.9 |
| Azidopine | 10−5 | −42.0 ± 7.1 | −6.9 ± 6.2 |
| Verapamil | 10−5 | −16.8 ± 2.6 | 7.0 ± 1.8 |
| Verapamil | 10−4 | −61.5 ± 5.3 | 18.8 ± 11.2 |
| Isradipine | 10−5 | −8.5 ± 7.1 | −15.2 ± 9.9 |
| Vinblastine | 10−5 | −1.6 ± 1.1 | −0.7 ± 4.2 |
| Cyclosporin A | 10−6 | 30.3 ± 7.2 | −1.7 ± 5 |
| Cyclosporin A | 5 × 10−6 | 260.2 ± 29.6 | −12.5 ± 5.1 |
| Quinidine | 10−5 | −4.1 ± 6.3 | 18.8 ± 22.9 |
| Quinidine | 10−4 | −48.4 ± 5.2 | 36.2 ± 15.1 |
| Glibenclamide | 10−5 | −13.8 ± 2.9 | 1.8 ± 6.6 |
| Glibenclamide | 10−4 | −46.5 ± 1.5 | 42.4 ± 14.8 |
Conductances are expressed as inverse half-times of lysis of ZG as described in the Experimental Procedures section. Control K+ and Cl− conductances were 4.26 ± 1.01 and 1.13 ± 0.22 h−1, respectively. Data are means ± S.D. of three to seven different experiments.