Fig. 5

Na⁺- and Ca²⁺-concentration dependences of Na⁺-induced inward current. a Current–voltage relationships of Na⁺-induced current with extra-mitochondrial 12.5, 25 and 50 mM Na⁺ (n = 5). b Extra-mitochondrial Na⁺ concentration dependence of Na⁺-induced inward current. Current was measured at −150 mV and normalized to the current induced by 50 mM Na⁺. Fitted half-maximum concentration and Hill coefficient are 35.6 mM and 3.7, respectively. c Current–voltage relationships of 50 mM Na⁺-induced current with 0, 1 and 10 μM Ca²⁺ in the pipette solution (n = 6–15). d Intra-mitochondrial Ca²⁺ concentration dependence of inward current at −150 mV. **p < 0.01 vs current without Ca²⁺ in pipette