Role of ASICs channels after excitotoxic damage in a model of spinal cord injury

MAZZONE GL, VEERARAGHAVAN P, GONZALEZ-INCHAUSPE C, NISTRI AAND UCHITEL OD

Buenos Aires

Congreso; 2nd FALAN Congress; 2016

La Federación de Asociaciones Latinoamericanas y del Caribe de Neurociencias (FALAN)

Extracellular glutamate concentration evokes excitotoxic damage that causes locomotor impairment and neuronal loss. Acid-sensing ion channels (ASICs) exert an important role for pH sensor in pathologies associated with acidosis and neurodegeneration. We have shown that 1h kainate application largely destroys neurons via excitotoxicity (Mazzone et al, 2010). Our present goal was to enquire how kainate could modulate ASICs expression, locomotor function and cell death. Mouse organotypic spinal slices (22 DIV) were treated with kainate (0.01 or 0.1 mM) for 1h, and washed for 24h prior to analysis. The evaluation of cell viability by propidium iodide staining demonstrated strong kainate-induced damage. RT-PCR results showed that kainate (0.01 mM) increased the mRNA expression of ASIC1a, ASIC1b, ASIC2 and ASIC3. 4´,6-diamidino-2-phenylindole (DAPI, 3.5 µM), a potent ASICs inhibitor, decreased mRNA expression levels. Immunohistochemistry indicated a much larger loss of neurons using kainate followed by delayed DAPI and amiloride (100 µM) treatment. Electrophysiological recording from isolated spinal cords showed that fictive locomotion, slowed down by kainate, was fully abolished by continuous application of DAPI or amiloride. Thus, our data indicate that early rise of ASICs channels after excitotoxic damage are necessary for neuronal survival, with a potential effect on network plasticity and implications for neuroprotective strategies. Supported by FLENI and CONICET.