Figure 6.

Concentration-dependent inhibition of VDCC currents by nifedipine in 2 mM [Ba²⁺]_o or 2 mM [Ca²⁺]_o. VDCC currents elicited by depolarizing voltage steps to +10 mV from a holding potential of −80 mV. (A) Effect of increasing concentrations of nifedipine in bath solution containing 2 mM [Ba²⁺]_o. (B) Effect of increasing concentrations of nifedipine in bath solution containing 2 mM [Ca²⁺]_o. Traces in red represent currents obtained in cells prior to the addition of nifedipine. Traces in blue represent current traces obtained in cells following washout of 1 μM nifedipine. (C) Concentration-inhibition curves of nifedipine on VDCC currents obtained in bath solution containing either 2 mM [Ba²⁺]_o or 2 mM [Ca²⁺]_o.