Journal of Neuroscience, Vol 4, 1442-1452, Copyright © 1984 by Society for Neuroscience
Acetylcholine metabolism in rat spinal cord cultures: regulation by a factor involved in the determination of the neurotransmitter phenotype of sympathetic neurons
MC Giess and MJ Weber
Acetylcholine metabolism has been studied in sister cultures of E13 rat
spinal cord cells cultured for 1 to 3 weeks with or without conditioned
medium (CM) from rat skeletal muscle cells. Spinal cord cells grown with CM
synthesized and accumulated 3 to 4 times more [3H]ACh from [3H]choline than
cultures grown without CM. This effect of CM was accompanied by a
comparable increase in CAT activity and could not be mimicked by increasing
the density of the spinal cord cultures. A 2- to 3-fold increase in AChE
activity was also observed in 2- to 3-week-old CM cultures, whereas the
activity of lactate dehydrogenase was identical in cultures grown with and
without CM. We have compared the effects of CMs from various non-neuronal
cell cultures on [3H]ACh synthesis and storage by spinal cord cultures and
by sympathetic neuron cultures. CM by skeletal muscle greater than skin
fibroblasts greater than rat heart muscle greater than C6 glioma cells were
the most active on both types of neuron cultures, whereas CM from rat
brain, L6 myoblasts, mouse 3T3, and PYT21 fibroblasts was inactive on
spinal cord cultures and only weakly active on sympathetic neurons.
Serum-free CM from skeletal muscle was inactive on both types of neuron
cultures. The CM factor active on spinal cord cultures has been purified
several thousand-fold by using a four-step fractionation scheme which has
previously led to a partial purification of the CM factor involved in the
regulation of CAT, AChE, and catecholamine-synthesizing enzymes in
sympathetic neuron cultures ( Swerts , J. P., A. Le Van Thai, A. Vigny ,
and M. J. Weber (1983) Dev. Biol. 100: 1-11). Moreover, a comparison of
dose-response curves established with this purified material showed that it
exerted its effects on spinal cord and on sympathetic neuron cultures in
the same range of concentration. Thus, these results suggest that the same
macromolecule is involved in the regulation of neurotransmitter phenotype
in both types of cultures despite their different embryological origins.