Figure 6. Time course of Mn²⁺ influx into mouse skeletal muscle cells.

Mn²⁺ quenching of the fura-2 fluorescence signal (F₃₈₀; cps, counts s⁻¹) was monitored in muscle fibres that were Ca²⁺ depleted in the presence of CPA. Downward arrows indicate addition of 0.5 mm Mn²⁺ to the 0Ca-5K solution while upward arrows indicate washout of Mn²⁺. The final steady fluorescence level was almost the same as the intrinsic fluorescence level.