Effects of Ca²⁺_o and Ba²⁺_o on peak I-V relations. Values were averaged and normalized as described in Materials and methods. Ca²⁺_o (A and B) and Ba²⁺_o (C and D) were varied from 100 nM to 110 mM. 10–12,¹¹¹² are based on data from the same cells as 2–5,³⁴⁵. Note that symbol and color coding for different concentrations is the same for Fig. 10 and Fig. 11, A–D.