Fig. 10. Epicardial cell differentiation into smooth muscle-like cells. Epicardial cells are obtained from an E11.5 mouse heart explanted in culture on a collagen coated glass coverslip. After 5 days, small round or spindle-shaped like calponin positive cells are scattered between unstained epicardial cells from a wild-type heart (A). This is shown at higher magnification in B. These same cell types were also seen in the Cx431 knockout heart explants (C).