HUMAN CENTRAL NEUROCYTOMA CELLS SHOW NEURONAL PHYSIOLOGICAL-PROPERTIES IN-VITRO

Central neurocytoma is a rare brain tumor composed of small round syna ptophysin-positive cells, suggesting a neuronal origin of these tumor cells. Glial properties are inferred, however, from the observation th at the tumor cells exhibit a strong morphological similarity to oligod endroglioma cells and show an astrocytic differentiation in vitro. To test for neuronal or glial physiological properties, we studied cultur ed neurocytoma cells derived from a surgical specimen from a 44-year-o ld man, employing the patch-clamp technique. Early primary cultures we re composed of morphologically unique bi- or multipolar cells which we re positive for synaptophysin and negative for the astrocyte marker gl ial fibrillary acidic protein. In the majority of these cells, whole-c ell membrane current recordings revealed physiological properties of n eurons, i.e., a high density of Na+ currents, the capacity to generate action potentials, and the expression of ionotropic neurotransmitter receptors. Metabotropic neurotransmitter receptors could be demonstrat ed by Ca2+ imaging techniques. The remaining bi- or multipolar cells a nd almost all cells in later culture stages and in vitro passage lacke d these neuronal properties and showed physiological features characte ristic of glial cells. We conclude that the major population of neuroc ytoma cells shows physiological properties of neurons and that with ti me in culture this population is replaced by electrically passive cell s.