Figure 1.

Cx43 channels are permeable to IP₃. Three different Cx43 cell pairs are shown (A,C,E) that all showed increased Ca²⁺ fluorescence in cell 1 (red lines) when IP₃ was introduced, and 10 to 40 seconds later a response in cell 2 (green lines) after it had permeated through Cx43 channels (B,D,F). In the pairs shown in A-D, 500 µM IP₃ was in the pipette. In the pair shown in E-F, 250 µM IP₃ was in the pipette. The mean gap junctional conductance (± SD) for the three Cx43 cell pairs shown was 23 ± 4.7 nS.