TABLE 1.
Potencies of mibefradil and ML218 to inhibit calcium influx produced by PROG, PGE1, l-sirenin, and high K+/high pH in human sperm
| Opener | Blocker | pIC50 | n |
|---|---|---|---|
| PROG | mibefradil | 5.17 ± 0.24 | 7 |
| ML218 | 5.02 ± 0.08 | 4 | |
| PGE1 | mibefradil | 5.08 ± 0.31 | 8 |
| ML218 | 4.87 ± 0.15 | 3 | |
| l-sirenin | mibefradil | 5.09 ± 0.34 | 5 |
| ML218 | 4.85 ± 0.17 | 3 | |
| high K+/high pH | mibefradil | 4.76 ± 0.09 | 8 |
| ML218 | 4.99 ± 0.16 | 7 |
Inhibitors were evaluated in the presence of an EC80 concentration of each activator (30 nM PROG, 10 nM PGE1, 3 µM l-sirenin). Buffer containing 140 mM K+, pH 8.2 was added to elicit alkalinization/depolarization calcium influx. pIC50 values are expressed as the mean ±SD with the number of independent experiments indicated by n.