Figure 5.

Representative confocal images from a control heart (upper three parts) and a Cre⁺;Cx45^fl/fl heart (lower three parts) showing lack of Cx45 staining in the ventricle of the cardiac-restricted Cx45-deficient heart (lower left part). Adjacent tissue sections were stained for Cx45, Cx43 and Cx40, and every effort was made to select the same region in each heart for comparison. The ventricular chamber is at the bottom of each field. The subendocardial conduction system can be seen most clearly in the images stained for Cx40 (right parts). Cx43 and Cx45 are each expressed in this same region as well as in the ventricular myocardium beyond the subendocardial layer in the control heart (upper middle and left parts, respectively). Cx43 immunostaining is comparable in the control and Cre⁺;Cx45^fl/fl hearts (upper and lower middle parts, respectively). Bars = 10 µm.