FIGURE 9.

Conductance-voltage relationships of heterotypic GJs composed of Cx46D3N and Cx50D3N, each paired to wild-type Cx46 and Cx50 and showing similar properties consistent with dominance of CxD3N hemichannel gating. G is plotted as a function of V_j, with G defined as above in Fig. 8. Positive and negative V_j refers to depolarization and hyperpolarization, respectively, of the cell indicated on the right side of the pairing designation. The panels show plots of steady-state G versus V_j for (A) Cx46/Cx46D3N GJs, (B) Cx50/Cx50D3N GJs, (C) Cx46/Cx50D3N GJs, and (D) Cx50/Cx46D3N junctions. In all junctions, G changes asymmetrically about V_j = 0, declining to near-zero with V_j relative negative on the D3N side. This result is consistent with closure of the negative gate of the D3N hemichannel in each case. Moderate reductions in G at V_j values relative to positive on the D3N side are consistent with closure of the negative gate in wild-type Cx46 and Cx50 hemichannels.