Quantitative assessment of AMPA receptor mRNA in human spinal motor neurons isolated by laser capture microdissection

Disturbance of glutamate neurotransmission may contribute to the motor neuron injury seen in amyotrophic lateral sclerosis. Previous studies have suggested that human spinal motor neurons express a specific profile of the AMPA subtype of glutamate receptor with low mRNA expression for the GluR2 AMPA receptor subunit but other studies have contested this finding. The present study uses laser capture microdissection to isolate specifically identified neurons coupled with quantitative RT-PCR to demonstrate that the level of expression of the GluR2 subunit is lower in spinal motor neurons than in dorsal horn neurons from the same spinal cord region. Thus, it is likely that human spinal motor neurons express a proportion of Ca2+-permeable AMPA receptors which may contribute to the selective vulnerability of these cells in amyotrophic lateral sclerosis.