Glutamate neurotoxicity and Huntington's chorea

Abstract

MCGEER and McGeer¹ recently reported that an intrastriatal injection of glutamate results in biochemical changes in brain similar to those associated with Huntington's chorea. They postulated that glutamate, a putative excitatory transmitter and an ‘excitotoxin’ abundantly present in brain may have a role in the pathophysiology of Huntington's chorea. Their evidence for this postulate must be considered very preliminary, however, as the biochemical changes induced by a 50 nmol dose of glutamate were not striking and it was not determined whether these changes were accompanied by neuronal degeneration¹. We have, injected various doses of glutamate directly into the rat striatum and examined the striatum for histopathological changes 21 d later. Here we report that doses of glutamate much higher than 50 nmol definitely cause striatal neurones to degenerate, whereas no neurotoxic reaction results from injecting equally high doses of control compounds such as NaCl or γ-aminobutyric acid (GABA).