SOD1 and amyotrophic lateral sclerosis: Interestingly, this receptor experiences an important reduction in spinal motor neurons in the classic murine model of ALS, based on the G93A mutation of the SOD1 gene, thus predisposing these neurons to excitotoxicity [19], a result also found in a further study measuring CB1 receptor sensitivity with neurophysiological recordings in the same experimental model [20].