Authors: Qing Chang and Lee J. Martin

Qing Chang

Johns Hopkins University; Baltimore, MD USA

Lee J. Martin

Corresponding author: martinl@jhmi.edu
Johns Hopkins University; Baltimore, MD USA

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Abstract:

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by selective loss of motoneurons. Recently we studied glycine receptors (GlyRs) in motoneurons in an ALS mouse model expressing a mutant form of human superoxide dismutase-1 with a Gly93→Ala substitution (G93A-SOD1). Living motoneurons in dissociated spinal cord cultures were identified by using transgenic mice expressing eGFP driven by the Hb9 promoter. We showed that GlyR-mediated currents were reduced in large-sized (diameter > 28 μm) Hb9-eGFP+ motoneurons from G93A-SOD1 embryonic mice. Here we analyze GlyR currents in a morphologically distinct subgroup of medium-sized (diameter 10-28 μm) Hb9-eGFP+ motoneurons, presumably gamma or slow-type alpha motoneurons. We find that glycine-induced current densities were not altered in medium-sized G93A-SOD1 motoneurons. No significant differences in glycinergic mIPSCs were observed between G93A-SOD1 and control medium-sized motoneurons. These results indicate that GlyR deficiency early in the disease process of ALS is specific for large alpha motoneurons.

Article Addendum to:
I Goussakov, MB Miller, GE Stutzmann. NMDA-mediated Ca(2+) influx drives aberrant ryanodine receptor activation in dendrites of young Alzheimer's disease mice. J Neurosci 2010; 30: 12128-37
PMID: 21414903 DOI: 10.1523/JNEUROSCI.24