The effect of Marcaine on muscle and non-muscle cells in vitro.

The effect of the local anaesthetic Marcaine on muscle and non-muscle cell types was examined using an in vitro assay. Each of the cell types examined (myotubes, myoblasts, fibroblasts and liver parenchyma) expressed morphological alterations when incubated in Marcaine-medium. Myotubes were the most sensitive of the cells studied and exhibited several pronounced membrane structural changes after short incubation periods in Marcaine-medium. The toxic effects of Marcaine were irreversible and the myotubes continued to degenerate despite being placed in fresh medium. Myoblasts and non-muscle cells, however, demonstrated a rapid recovery when removed from the Marcaine-medium. Since Marcaine is thought to complete with Ca++ for specific sites on cell membranes, it is proposed that the differential effects which were observed are dependent upon the level of calcium related activities being carried out by the cells.