Granule neurons were prepared from newborn rat cerebellum (8 days after birth).
These cells represent a good model to study cellular, chemical, or electrical properties. The life span of cerebellar granule neurons in culture is known to be relatively short, and after eight days cultures, cells become sensitive to glutamate. Immature cells are glutamate receptors negative. However during development, they exhibit an increase in the expression of glutamate receptors.
Five days challenge to electromagnetic field exposures showed a 30% decrease of cells survival, while only 5% of mortality was reported for unexposed samples. Additionally, blocking the glutamate receptor (with the glutamate competitor MK-801) no toxicity effect after exposures and glutamate was detected.
The kainate-induced currents from 6 days old exposed cells exhibited a significant increase compared to control cells.
Western blot and RT-PCR analyses showed that electromagnetic field exposure of the cerebellar granule neurons induces a change in both glutamate receptor proteins and mRNAs expression compared to control.
In addition, the use of antibody raised against neurofilament protein (NF-200) revealed an increase in NF-200 synthesis in the exposed cells.
No differences in heat shock protein expression were revealed suggesting that exposed cells are not undergoing stress induced by heat effect.
All these data suggest that exposure to non-ionizing radiations contribute to a premature expression of glutamate receptors reducing the life span of cerebellar granule neurons, leading to a more rapid cell maturation.