Excitotoxicity Current research suggests an excess of a naturally occurring brain chemical called glutamate in the synaptic cleft triggers a cascade of events that ends in cell death.
Glutamate excess occurs when it isn t removed after nerve cells signal to one another.
Excess g lutamate is neurotoxic because it over-stimulates specific neuronal metabolic functions. This overexposure causes the motor neurons to take in too much calcium, leading to the disruption of many cellular functions and, eventually, to cell death. The drug riluzole is thought to work by reducing the amount of glutamate released when nerve cells signal. Some researchers believe motor neurons die in ALS when they re subjected to highly charged destructive molecules called free radicals. Accumulation of free radicals leads to nerve cell damage and cell death.