Figure 4. The kinetics of hemichannel activation determined from the response to a +40 mV voltage step in representative cells expressing (A) Cx46 or (B) the combined cRNA derived from the mixture of Cx43 and Cx46 (Cx43•Cx46). For both types of hemichannels, the activation time course was best fit with a two-exponential function. The mean activation time constants (τ) are shown for Cx46 (n=9) and Cx43•46 (n=12). Note that Cx43•46 hemichannel currents exhibit faster activation kinetics than homomeric Cx46 hemichannels.