FIGURE 3.

Kinetics of HCN2 current are unaffected by hypoosmotic cell swelling. HCN2 channels and AQP1 were expressed in X. laevis oocytes and currents were activated by a step protocol as indicated. (A) Initially, currents were recorded in oocytes superfused by an isoosmotic extracellular solution (black traces). The oocytes were then exposed to hypoosmotic extracellular solution for 4 min and currents were recorded (shaded traces). (B) Normalized current traces from A. (C) The corresponding I-V curves (plotted as the current measured at the end of the hyperpolarization versus voltage). (▴) Currents recorded in isoosmotic solution. (○) Currents measured in hypoosmotic solution.