Excitatory Amino Acid Agonists/toxicity; Motor Neurons/drug effects; Neurotoxins/toxicity; Parvalbumins/pharmacology; Amyotrophic Lateral Sclerosis/etiology; Animals; Blotting, Western; Calcium/metabolism; Calcium Signaling/drug effects; Cell Death/drug effects; Cells, Cultured; Cytoprotection/drug effects; Cytoprotection/genetics; Dose-Response Relationship, Drug; Enzyme-Linked Immunosorbent Assay; Kainic Acid/toxicity; Mice; Mice, Inbred C57BL; Mice, Transgenic; Motor Neurons/cytology; Motor Neurons/metabolism; Organ Specificity; Parvalbumins/genetics; Parvalbumins/metabolism; Phenotype; Posterior Horn Cells/cytology; Posterior Horn Cells/drug effects; Posterior Horn Cells/metabolism; Receptors, AMPA/metabolism