The aetiology of the neuronal death which occurs in neurodegenerative diseases is still unknown. These disorders are of insidious onset and follow an inexorable, gradually progressive course. The best known and most frequent are Alzheimer's disease (AD), Parkinson's disease (PD) and amyotrophic lateral sclerosis (ALS).
Advances in molecular genetics and neurobiochemistry towards the understanding of processes involved in cell death, suggest the association of phenomena of excito-toxicity and oxidation damage in the selective degeneration of neuronal populations, characteristic of these disorders.
The evidence presented here suggests that the species reactive to oxygen (SRO) play a direct part in the aetiology and/or pathogenesis of neurodegenerative disorders, although it is still very difficult to establish whether these reactive species represent the primary etiological factor, or are toxic products secondary to tissue damage.