Figure 5. MDL-12,330A does not influence currents through voltage-dependent Ca²⁺ channels.

We employed extracellular Ba²⁺ to replace Ca²⁺ as the charge carrier to amplify current responses through Ca²⁺ channels during the stimulus of depolarization. Ba²⁺ currents were recorded in conventional whole-cell configuration from a holding potential of −70 mV to various depolarizing voltages (−50 to 20 mV). A. representative current traces recorded under the treatments as indicated. B. current-voltage relationship curves of Ca²⁺ channels from rat beta cell. C. summary of the mean current density of Ba²⁺ currents recorded at 0 mV depolarization. Control (Ctrl, n = 6); MDL-12,330A (MDL, 10 µM, n = 6).