Mitosis in beating cardiac myoblasts treated with cytochalasin‐B

Time‐lapse pictures of isolated chick cardiac myoblasts grown in a medium with cytochalasin‐B reveal that normal mitotic chromosomal separation and muscle contraction can take place simultaneously. These observations indicate that the contractile stimulation for the cells' myofibrils does not affect the movement of the chromosomes and that the cell can regulate two different motile systems inside one cell.