Figure 7.

Fast reversal of asymmetric g_j–V_j dependence by reversal of transjunctional gradient of [Mg²⁺]_i. A, Changes in I_j during consecutive 35-s-long V_j ramps from 0 to −100 mV and from 0 to 100 mV. Initially, cell-1 was loaded with a control/standard pipette solution (MgCl₂, 1 mm) and cell-2 contained MgATP (Aa). From ∼9 to 14 min after onset, pipette-2 was carefully detached and replaced with a pipette containing K₂ATP (Ab) reversing the Mg²⁺ gradient. From ∼25 to 30 min after onset, pipette-2 was replaced with a pipette containing MgATP (Ac) reversing the Mg²⁺ gradient once again. B, g_j–V_j plots (normalized to initial g_j value at V_j = 0) from ramp pairs in (A) designated with numbers 1 and 2 (Ba), 3 and 4 (Bb), and 5 and 6 (Bc).