Figure 6.

Visualization of cyclic nucleotide passage through Cx43 and Cx50 gap junction channels using fluorescent ε-cAMP. (A) A pipette filled with 5 mM ε-cAMP was attached to a single cell within a group of HeLa cells expressing Cx43. After opening the patch in whole-cell mode, (B) dye transfer was detected to half of the neighboring cells within 5 minutes, and (C) a majority of the cells within 10 minutes. (D) In Cx50 transfected HeLa cells, (E, F) negligible transfer of ε-cAMP to neighboring cells was observed at 5 or 10 minutes following the opening of the patch pipette.