[K⁺]_o – dependence of the effect of internal Ba²⁺ on current through mKv1.3 A, mKv1.3 currents elicited by voltage ramps from -120 to +80 mV in 4.5 mM K⁺-Ringer or 160 mM K⁺-Ringer outside and 2 mM Ba²⁺ in the pipette-solution.