Abstract
Dibucaine, a local anaesthetic, reversilbly suppressed growth and differentiation of cultured chick myogenic cells. In the presence of 10 μM dibucaine, chick myoblasts multiplied and fused to form myotubes. However, myotubes did not increase their size. Accumulation of creatine kinase (CK) activity per culture dish was also suppressed, showing that myotube growth was suppressed. Concomitantly, myofibril formation and developmental transition of CK isozymes were retarded. The myotubes remained immature. When dibucaine was removed from the culture medium and cells were further incubated, the accumulation of CK activity, especially of muscle type isoform, and formation of myofibrils took place ; eventually the myofibrils were organized similarly to those in the control culture. The concentration of dibucaine enough to exert these effects was about one-hundredth of the concentration used in clinical anaesthesia.
