Figure 4.

Correlation between Lv-Kir2.1 titer and Kir2.1 current. (A) Ba²⁺ concentration–Lv-Kir2.1 titer relationship (n = 4). (B) Ba²⁺ concentration–Kir2.1 conductance relationship (n = 4). These relationships were fitted to the Hill equation (four parameters). (C) Correlation between Kir2.1 conductance and lentiviral titers at various concentrations of BaCl₂. Values were normalized to that of 0.003 mM BaCl₂ and were fitted by linear regression (R ² = 0.74). (D) Changes in the membrane potential at higher extracellular K⁺ concentrations. Tyrode’s solution, in which the K⁺ concentration was varied, was perfused sequentially. (E) Extracellular-K⁺-concentration-dependent increase in the titer of Lv-Kir2.1. Lentiviral vectors were prepared with medium containing 5, 13, 21, or 29 mM KCl. We determined the lentiviral titers and found significant differences at different extracellular K⁺-concentrations (p < 0.0000000001, analysis of variance [ANOVA], n = 4). (F) Correlation between membrane potential and the Lv-Kir2.1 titer at various extracellular K⁺ concentrations. Values are the means of four experiments and were fitted with linear regression (R ² = 0.93).