Effect of phenytoin on proliferation and differentiation of mouse muscle cells in vitro.

Effect of a commonly used anti-convulsant drug, phenytoin, was studied a four dose levels (5, 15, 50 and 100 micrograms/ml) on neonatal Bar Harbor mouse muscle in vitro. The cultures were exposed to the drug suspended in the growth medium at the end of 72 hrs, prior to the fusion of the cells. The effects of the drug were dose dependent. At high concentration (50 and 100 micrograms/ml), it hampered cell proliferation and prevented myoblasts from fusing to form multi-nucleated myotubes. Lower concentrations of phenytoin allowed cells fusion to occur, but the total cell count was decreased at 15 micrograms/ml.