Table 1.
Effects of experimental manoeuvres on [Mg2+]i-dependent modulation of ICa
| Experimental manoeuvres | Decrease in ICa density (%)† |
|---|---|
| Patch electrode Ca2+ ([Ca2+]p) | |
| ∼1 nm | 45 ± 2.7 (8)* |
| 100 nm | 64 ± 2.8 (10) |
| 300 nm | 71 ± 3.5 (6) |
| Change cytosolic Ca2+ buffering | |
| 10 μm Ryanodine | 71 ± 3.8 (5) |
| 5 mm BAPTA + 15 mm EGTA | 56 ± 3.5 (6) |
| Calmodulin blocker | |
| 50 μm W7 | 60 ± 4.9 (5) |
| Ca2+/calmodulin kinase II blockers | |
| 5 μm KN-93 | 59 ± 5.7 (6) |
| 100 μm AIP | 63 (3)‡ |
| Ca2+/calmodulin phosphatase | |
| 2B blockers | |
| 10 μm CsA | 56 ± 5.8 (6) |
| 10 μm CAP | 56 ± 2.5 (8) |
Values of n given in parentheses. †Percentage decrease of peak ICa at 0 mV in cells voltage-clamped with patch electrodes containing 1.8 mmversus 0.2 [Mg2+]p, calculated by Fieller's theorem (Goldstein, 1964). ‡The number of replicates is too small to calculate the mean and 95% Confidence Interval of the ratio, and therefore, the s.e.m. using Fieller's theorem. As a result, the ratio of the mean current density with 1.8 mm and 0.2 mm[Mg2+]i is listed. AIP, autoinhibitory peptide; CAP, calcineurin autoinhibitory peptide.
*
Significantly different from experiments with [Ca2+]p equal to 100 nm.