FIGURE 5.

Effects of apamin and barium on APs measured with constant and I_K1 current injection. (A) Typical APs of one atrial myocyte in absence (baseline) and presence of apamin to block the Ca²⁺-dependent K⁺ current. (B) Average AP parameters measured in five cells in presence of apamin. AP parameters are normalized to the AP parameters measured under baseline conditions in the same cell. (C) Typical APs of one atrial myocyte in absence (baseline) and presence of barium to block the native I_K1. (D) Average AP parameters measured in four cells in presence of barium. AP parameters are normalized to the AP parameters measured under baseline conditions in the same cell. *p < 0.05, drug vs. baseline (paired t-test).