Adrenal chromaffin cells are commonly used in studies of exocytosis. Progre
ss in characterizing the molecular mechanisms has been slow, because no sim
ple, high-efficiency technique is available for introducing and expressing
heterologous cDNA in chromaffin cells. Here we demonstrate that Semliki For
est virus (SFV) vectors allow high-efficiency expression of heterologous pr
otein in chromaffin cells.