Cultures of zona ependyma cells of goldfish brain: an immunological study of the synthesis and release of ependymins.

Two proteins (ependymins beta and gamma) localized within specific cells in the zona ependyma of goldfish brain were identified in previous studies in our laboratory as extracellular factors whose metabolism was highly increased by the acquisition of new patterns of behavior. Methods for growing zona ependyma cells in culture were developed to determine if cells within this tissue could synthesize and release the ependymins into their extracellular environment. Dissociated cells from zona ependyma were grown as primary monolayer cultures on polylysine-coated slides. The cultures survived for at least 4-5 weeks, forming an intricate network of interconnecting processes. These contained many cell types, several of which retained their in vivo immunohistochemical properties. Specific populations of cells staining with antisera to nerve growth factor, glial fibrillary acidic protein, and ependymins beta and gamma were present. Radioimmunoassay, immunoelectrophoresis data, and labeling experiments indicate that cells within the cultures can synthesize the ependymins de novo and release them into their extracellular environment. These results are consistent with the hypothesis that the ependymins might function as extracellular factors which mediate the behaviorally induced plasticity of the goldfish CNS. In this respect they resemble other "protein factors" which stimulate the growth and morphological differentiation of nervous system cultures.