title: Endogenous and exogenous factors support neuronal survival and choline acetyltransferase activity in embryonic spinal cord cultures.
abstract: Dissociated 4-day (stage 23) chick embryo lumbar cord cells were cultured at low or high cell densities for 1 or 5 days in the presence or absence of added spinal neuronotrophic factor (supplied as RN22 Schwannoma conditioned medium, RCM). In low density, 1-day cultures neuronal survival was dependent on added RCM whereas by 5 days no neurons survived, even in the presence of RCM. In high density 1-day cultures a substantial neuronal population could survive even without added RCM and a large proportion of this neuronal population would survive for 5 days. When conditioned media from high density lumbar cord cultures was supplied to low density unsupplemented cultures, a similar level of 5-day neuronal survival resulted. However, no neurons survived in RCM-supplemented 5-day high density cultures, indicating the presence in RCM of a material toxic for the neurons. Both the RCM and the high density lumbar culture-conditioned medium supported considerable choline acetyltransferase activity indicating the presence within these cultures of motoneurons.
mesh_terms: D000818:Animals; D002470:Cell Survival; D002478:Cells, Cultured; D002642:Chick Embryo; D002795:Choline O-Acetyltransferase / Q000378:metabolism*; D007700:Kinetics; D009474:Neurons / Q000201:enzymology / Q000502:physiology*; D013116:Spinal Cord / Q000196:embryology / Q000201:enzymology / Q000502:physiology*
chemical_list: D002795:Choline O-Acetyltransferase