Consequences of hypoxia on the cell size of neuropeptide-Y neurons and the role of ascorbate in cultured neurons from chick embryo.

The effect of ascorbate on the cell size of neuropeptide-Y neurons (NPY) and ascorbate uptake was studied in hypoxic neuronal cultures from chick embryo. Primary neuronal cultures plated on coverslips or on plastic dishes were switched to the serum free or serum supplemented medium and exposed to the normoxia or hypoxia for 8 h. Vehicle (homocysteine) or L-ascorbic acid was added to the incubation medium at 0 h. Cell size and relative optical density of NPY positive neurons on coverslips were measured by image analysis and ascorbate content in the cell culture on dishes was determined by HPLC. Hypoxia increased the size of NPY neurons in vehicle treated cultures but not in ascorbate supplemented cultures containing serum free or serum supplemented medium. Contrastingly, normoxic NPY neurons were damaged by ascorbate in serum free medium and not by incubation with ascorbate in serum supplemented medium. These results indicate that the inhibition of hypoxic induced neuronal swelling by ascorbate is consistent with its antioxidant properties and presence of ascorbate in serum free medium under normoxic conditions may act as a proxidant for cultured neurons.