New Spinal cord models: Characterization of Excitotoxicity and Neuroprotection

Group III metabotropic glutamate receptors (mGluR III) are known to decrease glutamate release and to play an important role in controlling pain as documented in neuropathic pain models. Much less is known about their potential neuroprotective effect against excitotoxicity that is considered important for damage onset of spinal cord injury. Using rat spinal cord organotypic slices model, we investigated if mGluR III receptor activation might contrast excitotoxic cell death evoked by kainic acid (0.1 mM) applied for 1h and followed by wash for further 24h. The specific agonist of mGluR III receptors L-(+)-2-amino-4-phosphonobutyric acid (L-AP4; 1 µM) was either co-applied with kainic acid or administered during washout. Cell death was quantified in terms of percentage of pyknotic nuclei, total number of neurons, motoneurons and astrocytes. Furthermore we developed for future long-term studies an in vitro model of Spinal Cord Isolated from newborn rats maintained for 3 days in medium. We characterize this model using both immunohistochemistry and electrophysiological recordings.