Figure 2. L-type Ca²⁺ current evokes exocytosis in AII amacrine cells.

Ai: Capacitance changes in AII-amacrine cells are inhibited by nitrendipine (10 μM) and isradepine (1 μM). Typical depolarization-evoked (500 ms; from −80 to −10 mV) exocytosis (ΔC_m) from an AII-amacrine cell under control conditions (black) and after bath application of nitrendipine or isradepine (red). Aii: Bar graph summarizing ΔC_m under control conditions and after drug application. Individual cells are represented by open circles. Experiments were performed at 31°C. Statistical significance (paired t-test) is denoted by asterisks. Bi: Top: Average ΔC_m traces evoked by depolarization (100 ms pulse from −80 to −10 mV) from AII-AC under different external Ca²⁺ concentrations (1.15mM: n=6; 5.15mM: n=5). Bottom: Average ΔC_m traces evoked by depolarization (100 ms pulse from −80 to −10 mV) from AII-AC for various internal Ca²⁺ buffer concentrations (10 mM BAPTA: n=4; 2 mM EGTA: n=6; 0.2 mM EGTA: n=5). Bii: Summary plot of ΔC_m from individual AII-AC in various external calcium concentrations and internal calcium-buffers. Experiments were conducted at room temperature. Bar graphs denote mean ± SEM. Statistical significance (unpaired-t test) is denoted by asterisks.