Figure 7. Differential contribution of K⁺ channels to action potential repolarization and threshold and membrane potential minimum while firing at high rates (80 Hz).

A, action potential repolarization is slowed when K_v3.2 is deleted (Kv3.2) and unaffected when SK or Kv1 channels are blocked compared to controls (WT). B, action potential threshold (V_th) is lowered when Kv1 or SK channels are blocked, but unaltered when K_v3.2 is deleted compared to controls (WT). C, minimum membrane potential (Min V_m) is more hyperpolarized when Kv1 and SK channels are blocked, but more depolarized when K_v3.2 is deleted compared to controls (WT). D, overlay of firing rate curves for control (WT), SK channel blocker, Kv1 channel blocker, and Kv3.2 gene deletion demonstrate different roles for these K⁺ channels in regulating firing.