Figure 4.

Dye coupling in control, Li-treated, and Wnt-1–exposed cardiomyocytes. In each panel, phase contrast micrographs are to the left and fluorescence micrographs (using FITC excitation and emission filters) are shown to the right. (a) Untreated cardiac myocytes. (b) Cardiac myocytes treated for 24 hours with 20 mM LiCl. (c) Cardiac myocytes cocultured with parental N2A cells. (d) Cardiac myocytes cocultured with Wnt-1–expressing N2A cells. Photographs taken at 1 minute after dye injection. N2A cells are indicated by arrows, and injected cardiac myocytes are indicated by asterisks. Note that LiCl and Wnt-1 exposure significantly increases dye coupling among cardiac myocytes (differences in transfer efficacies, which are highly significant for both LiCl and Wnt-1 treatments, are presented in the text).