Cholinergic development in chick brain reaggregated cell cultures

Reaggregated cell cultures from dissociated 7-day-old chick embryo whole brains were prepared, and the developmental profiles of acetylcholinesterase and choline acetyltransferase, in the aggregates, determined over a 30-day period. Enzyme activities in vitro, at different times of culture, typically lie between 30 and 60% of the values obtained for embryos or chicks of the same developmental age, up to day-10 posthatching. The increase in acetylcholinesterase activity over a 24-day period of culture/incubation is fourfold in the aggregates vs. sixfold for embryos, while the choline acetyltransferase values increase, during the same period of time, 32-fold in the aggregates vs. 17-fold in vivo. Choline acetyltransferase activity seems to be more dependent on good cell-to-cell contact than acetylcholinesterase activity. On the other hand, morphological studies on the aggregates with light and electron microscopy reveal a number of structural features characteristic of well-developed nervous tissue. It is suggested that aggregate cultures of chick brain cells are an adequate model system that is especially useful in analyzing developmental phenomena requiring free tridimensional interaction.Abbreviations AChE acetylcholinesterase - ChAT choline acetyltransferase - BW284 C51 dibromide 1,5-bis-(4-allyldimethylammoniumphenyl)pentan-3-one dibromide - ACh acetylcholine