Kinetics of Slick channels during regulation by cell volume changes.

(A) Slick channels (Slick, black) or Slick channels and AQP1 (Slick+AQP1, red) were expressed in Xenopus laevis oocytes and were kept at a holding potential of −80 mV before the channels were activated by depolarization to +80 mV (500 ms). The recorded currents were normalized to the maximal current measured in each experiment at the end of the +80 mV depolarization period for two representative oocytes. (B) oocytes expressing Slick channels in absence of co-expressed AQP1 were activated by depolarizations to +80 mV as before in isotonic (black), hypotonic (blue) and hypertonic (red) media, and currents were normalized to the maximal current. The figure shows the result of one representative experiment. (C) the experiments shown in (B) were repeated with oocytes co-expressing Slick channels and AQP1 channels (in isotonic (black), hypotonic (blue) and hypertonic (red) media). The figure shows the result of one representative experiment (Note: the currents measured in isotonic and hypotonic media are precisely superimposed). (D) a representative oocyte co-expressing Slick and AQP1 was exposed to isotonic (black), hypotonic (blue) and hypertonic (red) media and in each medium Slick channels were activated by a depolarization protocol as in figure 1. The figure shows the resulting IV-curves, each normalized to the maximal current (found at +80 mV).