Neurolathyrism: mitochondrial dysfunction in excitotoxicity mediated by L-β-oxalyl aminoalanine

Abstract

β-N-Oxalyl amino-L-alanine (L-BOAA); synonym β-N-oxalyl-α,β-diaminopropionic acid (β-ODAP) is a naturally occurring non-protein amino acid present in the chickling pea from the plant Lathyrus sativus grown in drought prone areas. Ingestion of L-BOAA as a staple diet results in a progressive neurodegenerative condition, neurolathyrism, a form of motor neuron disease which affects the upper motor neurons and anterior horn cells of the lumbar spinal cord. L-BOAA is an excitatory acid and acts as an agonist at the AMPA receptor. One of the primary effects of L-BOAA toxicity is the inhibition of mitochondrial complex I selectively in the motor cortex and lumbar spinal cord. Recent evidence has suggested that the mitochondrial dysfunction is a consequence of oxidation protein thiol groups as a result of generation of reactive oxygen species. Mitochondrial complex I is highly to vulnerable to inactivation through oxidation of vital sulfhydryl groups. Thiol antioxidants such as α-liopic acid offer a method of protecting mitochondrial function. A common mechanism involving oxidation of protein thiol groups may underlie neurodegeneration occurring through mitochondrial dysfunction induced by excitatory amino acid.