Journal of Neuroscience, Vol 5, 160-166, Copyright © 1985 by Society for Neuroscience
Characterization of tissue-derived macromolecules affecting transmitter synthesis in rat spinal cord neurons
LM Kaufman, SR Barry and JN Barrett
Rat spinal cord cells maintained in neuron-rich cultures were exposed to
extracts of skeletal muscle or to medium conditioned by non-neuronal cells.
The conditioned media enhanced neuronal acetylcholine (ACh) synthesis,
choline acetyltransferase activity, and protein synthesis, and decreased
gamma-aminobutyric acid (GABA) synthesis. Muscle extract prepared from
newborn rats produced similar enhancements but did not depress GABA
synthesis. Muscle extracts prepared from normal and denervated adult rat
limbs contained relatively little activity. These results suggest that
different molecular factors might mediate the effects on GABA and ACh
synthesis. Gel filtration of conditioned media and muscle extracts revealed
that all of these activities were confined to a macromolecular fraction
with an apparent Mr of 40,000. These tissue-derived factors affecting
neuronal protein and transmitter synthesis are in turn distinct from a
neuronal survival-promoting factor obtained from serum (Kaufman, L. M., and
J. N. Barrett (1983) Science 220: 1394-1396).