Development of cholinergic markers in the neuroblastoma, N1E-115

The neuroblastoma, N1E‐115, was grown for 9 days after subcultivation. The development of acetylcholinestrase (AChE), choline acetyltransferase (CAT), QNB‐binding, choline uptake, and acetylcholine release was measured on days 1, 3, 6, and 9. In paralell experiments the irreversible AChE inhibitor soman was added to neuroblastoma on day 1 and the development of the above parameters except for release, was followed. AChE activity in the normal cells was found to develop also after confluency, whereas CAT activity and QNB‐binding followed the development of most of the cellular proteins, i.e., ceased to develop at confluency. Both choline uptake and acetylcholine release appeared independent of cellular development. In the soman‐treated cells the development of AChE was inhibited for up to 6 days and thereafter developed with the sama rate as in the normal cells. CAT and QNB‐binding developed as in the normal cells, but at a significantly reduced level. The development of choline uptake was not significantly different in soman‐treated and normal neuroblastoma. It is concluded that the development of the cholinergic marker QNB‐binding is intimately associated with that of the “presynaptic” marker CAT, whereas the development of AChE seems to be unrelated to these cholinergic parameters. The choline transport and the acetylcholine release seem to be equally well expressed on all the days studied.