Fig. 5. Single channel properties of gap junctions recorded from co-transfected N2aCx26/Cx43 cells compared to homotypic Cx26 channels. (A) Single channel recordings from pairs of co-transfected N2aCx26/Cx43 cells. A voltage ramp protocol (top panel)V_j=±100 mV, ramp duration 2 seconds) evoked single channel currents (middle panel) with a slope conductance (dashed line) corresponding to a unitary conductance g_j of 132-134 pS, which resembles homotypic Cx26 channels. The bottom panel shows another recording of one operational channel with channel rectification (g_j=94 pS at V_j=–100 mV and g_j=130 pS at V_j=100 mV). (B) Single channel recordings from pairs of homotypic N2aCx26 cells. (Middle panel) Single channel current elicited by voltage ramp protocol (V_j=±100 mV, 2 seconds) exhibited a unitary conductance, g_j of 136 pS. (Bottom panel) Single channel currents of homotypic Cx26 showed rectification (g_j=102 pS at V_j=–100 mV and g_j=140 pS at V_j=100 mV). (C) Superposition of gap junction currents from a co-transfected N2aCx26/Cx43-N2aCx26/Cx43 pair and from a homotypic N2aCx26-N2aCx26 cell pair suggests that the same type of channel was recorded in both cases (i.e. Cx26).