Cellular localization of the multiple molecular forms of acetylcholinesterase in cultured neuronal cells

The cellular localization of the molecular forms of acetylcholinesterase was explored in chick sympathetic neurons and in mouse T28 cells (neuroblastoma X sympathetic ganglion cell hybrids) using the reversible, poorly lipid-soluble inhibitor of acetylcholinesterase, BW284C51, to protect cell surface activity while inactivating cytoplasmic activity with DFP, an irreversible, lipid-soluble inhibitor. Our results show protection of over 80% of the chick 11 S form and over 90% of the corresponding mouse 10 S form under these conditions, while over 90% of the chick 6.5 S and mouse 4 S forms are inhibited. The results suggest that the avian 11 S and mouse 10 S forms are predominantly or exclusively ectoenzymes while the respective 6.5 S and 4 S forms are confined to the cytoplasm.