Fig. 3.

Effect of acidosis and Cd²⁺ (200 μM) on the steady-state voltage dependence of transient outward current (I_to) inactivation in Epi myocytes. Ai: extracellular acidosis (pH_o 6.5) without Cd²⁺ induced a right shift in inactivation (n = 4). Cd²⁺ right-shifted inactivation and reduced the shift induced by extracellular acidosis (n = 4). Aii: control and acidosis signals from the same cell (no Cd²⁺). Red signals clamped from −40 mV. Bi: intracellular acidosis (80.0 mM acetate) with (n = 5) or without (n = 4) Cd²⁺ had no significant effect on the voltage dependence of inactivation. Bii: control and acidosis signals from the same cell (no Cd²⁺). Red signals clamped from −40 mV. Smooth lines are best fits with Boltzmann functions (materials and methods). Inset: clamp protocol. The results in this figure are summarized in Table 1. Pacing CL = 5 s.