Figure 3.

Local calcium signals in the presence of 50 μM Fluo-3. (A–D) Local Ca²⁺ transients taken at two featured spots along the scanning line (red and blue lines and symbols) and the t-tubule membrane (black lines and symbols): circle −1.5 μm; triangles −5.3 μm. Membrane voltage at 0 mV [red and black lines in (A,B)] and at +50 mV [blue and black lines in (C,D)]. [Na⁺]_i 10 mM (solid lines) and [Na⁺]_i 0 mM (dash lines). (E–H) Calcium concentrations visualized as line-scan images in transverse cell direction for the cases described in (A–D).