Figure 2.

Contribution of Ca²⁺-dependent currents, SK_Ca and IK_Ca, to membrane currents in AECs. (A) Examples of ramp currents in the absence (black trace; E_rev = −78.4 mV) or in presence of 100 nM ChTX, an IK_Ca inhibitor, alone (ChTX, red trace, E_rev = −74.5 mV) or in combination with 300 nM Ap, a SK_Ca inhibitor (Ap, green trace, E_rev = −75.6 mV). The AEC was dialyzed with a pipette solution containing 5 mM HEDTA with 1 mM free Mg²⁺ and 3 μM free Ca²⁺. (B) Recording of currents as in A except that the cell was dialyzed without addition of Ca²⁺. IK_Ca and SK_Ca currents from the experiment presented in A were obtained as the ChTX- (C, E_rev = −75.4 mV) and Ap-sensitive (D, E_rev = −76.2 mV) currents, respectively. Currents were evoked by a 200-ms voltage ramp protocol from −100 to + 100 mV (HP = −60 mV).