FIGURE 9.

Gentamicin does not inhibit the intercellular transfer of ethidium or Lucifer yellow between HeLa-rCx26 –mCx43 cells. Gap junctional communication, expressed as dye coupling index, was evaluated in confluent cultures of HeLa-rCx26 or –mCx43 cells. A single cell was microinjected with ethidium (75 mM Etd in water) or Lucifer yellow (5% LY w/v in 150 mM LiCl) and the number of cells to which Etd or LY was transferred in 2 min was scored. Gentamicin was applied extracellularly or was included in the pipette at a final concentration of 200 μM. (A) Photomicrographs showing a fluorescent field of HeLa-xCx26 cells microinjected with Etd or LY and transfer to adjacent cells under control conditions and in the presence of 200 μM gentamicin applied extracellularly 5 min before the assay. Scale bar, 20 μm. (B) Quantitative analysis of dye coupling between HeLa-rCx26 and HeLa-mCx43 cells under control conditions (control) or treated with 200 μM gentamicin in the extracellular solution or in the pipette, as indicated. Bar graphs summarize the results of three independent experiments for each condition (the number of microinjections is indicated within each bar). Values correspond to the mean ± SEM of fluorescent cells.