Figure 8.

Both Ca²⁺-dependent and Ca²⁺-independent spontaneous release are enhanced, but to different extents, when MLCK is inhibited. A, B, Representative traces showing AII mEPSCs under control, and different combinations of removal of extracellular calcium (0 Ca), 10 μm BAPTA-AM and 100 μm ML-9 conditions. C, Summary data for AII mEPSC frequency under two experimental conditions in A (empty and full circles) and B (empty and full squares). The data under control and ML-9 conditions (adapted from Fig. 6B1, empty and full triangles, respectively) were also presented for direct comparison. The frequencies were normalized to the frequency under control condition in each cell before averaging across cells. The data were also illustrated as mean ± SEM. Wilcoxon signed-rank tests were used (control vs ML-9, n = 10, p = 0.0020; 0 Ca + BAPTA-AM vs 0 Ca + BAPTA-AM + ML-9, n = 9, p = 0.0039) except for comparison of 0 Ca and 0 Ca + ML-9 data by paired Student’s t test (n = 10, p = 0.0001); **p < 0.01, ***p < 0.001. D, Summary data for changes of AII mEPSC frequency after bath application of 100 μm ML-9 for 15 min under control and two experimental conditions. The change in each cell was calculated as the ratio of mEPSC frequencies before and 15 min after application of ML-9. The data were also illustrated as mean ± SEM. Mann–Whitney tests were used (ML-9 vs 0 Ca + ML-9, p = 0.0232; ML-9 vs 0 Ca + BAPTA-AM + ML-9, p =0.0030); *p < 0.05, **p < 0.01.