Low expression of GluR2 AMPA receptor subunit protein by human motor neurons

DISTURBANCE of glutamate neurotransmission may contribute to motor neuron injury in amyotrophic lateral sclerosis. There is evidence that human motor neurons may express a specific profile of glutamate receptors, with low or absent expression of mRNA for the GluR2 AMPA receptor subunit, which has a crucial role in controlling calcium permeability. This study, using an immunocytochemical approach with a GluR2 specific antibody, shows that human upper and lower motor neurons have a very low/absent expression of GluR2 protein, in contrast to many other neuronal groups. Thus, it is likely that human motor neurons express a high proportion of atypical, calcium permeable AMPA receptors which may contribute to selective vulnerability and may allow cell-specific modulation of the actions of glutamate. (C) 1999 Lippincott Williams & Wilkins.