Increased activity of choline acetyltransferase and acetylcholinesterase in developing cultures of chick spinal cord: a correlation with morphological development.

Explants of 10-12-day-old embryonic chick spinal cord were cultured for up to 20 days by the "coverslip-roller" method. Morphological development of neurons as shown by the presence of mature neurons, myelinated axons and synaptic structures, was demonstrated by light and electron microscopy. Two important enzymes associated with acetylcholine transmitter metabolism, choline acetyltransferase (ChAc) and acetylcholinesterase (AChE), were assayed in cultures at selected time intervals. The activity of ChAc and AChE exhibited an increase of 60 per cent and 80 per cent, respectively, over a 20-day period. It is concluded that organotypic cultures of embryonic chick spinal cord show differentiation not only in morphological aspects, but also in biochemical terms through progressive development of ChAc and AChE.