Molecular mechanisms of cellular injury produced by neurotoxic amino acids that generate reactive oxygen species.

There is now strong experimental evidence that the basic precursors for the synthesis of catechol(amine) and indolamine neurotransmitters, tyrosine and tryptophan can act as generators of ROS (reactive oxygen species): peroxides, superoxide and peroxyradicals. The consequences of free radicals formation from precursors during oxidative degradation process, their possible participation in electron transfer/addition reactions and chain processes involving cell antioxidant defense system were presented and discussed. Although the generation of neurotoxic ROS by tyrosine and tryptophan is accepted to occur in the presented model systems, doubts can exist as to the situation in vivo, which may be completely different and remain to be explored. The relevance of the present findings with regard to a variety of neurological diseases cannot be ignored.