Defective glutamate metabolism
Defective glutamate metabolism is one possible theories for the cause of ALS. The theory of pathogenesis of ALS is excito-toxicity of glutamate. Glutamate is a common chemical in the nervous system used by neurons to signal between one another. Glutamate is important for normal nerve cell function but is toxic in excess. There is evidence of increased glutamate in ALS patients and in ALS mice, which in turn, may be responsible for nerve cell death. The increased glutamate may result from either abnormal transport of glutamate out of the nerve cell environment or increased release of glutamate from nerve cells. There is some evidence that the transporter responsible for removing glutamate from the nervous system may be altered, in addition, or alternatively, the process for making the transport protein may have become damaged in ALS patients.