The AMPA Receptor Subunit GluR1 Regulates Dendritic Architecture of Motor Neurons

The morphology of the mature motor neuron dendritic arbor is determined by activity-dependent processes occurring during a critical period in early postnatal life. The abundance of the AMPA receptor subunit GluR1 in motor neurons is very high during this period and subsequently falls to a negligible...

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Bibliographic Details
Published in:The Journal of neuroscience 2002-09, Vol.22 (18), p.8042-8051
Main Authors: Inglis, Fiona M, Crockett, Richard, Korada, Sailaja, Abraham, Wickliffe C, Hollmann, Michael, Kalb, Robert G
Format: Article
Language:English
Subjects:
Action Potentials - drug effects
Action Potentials - physiology
Amino Acid Substitution
Animals
Dendrites - drug effects
Dendrites - physiology
Electric Stimulation
Fluorescent Dyes
Genetic Vectors - administration & dosage
Genetic Vectors - genetics
Immunohistochemistry
Life Sciences (General)
Male
Motor Neurons - cytology
Motor Neurons - drug effects
Motor Neurons - metabolism
Mutagenesis, Site-Directed
Oocytes - metabolism
Patch-Clamp Techniques
Perforant Pathway - physiology
Protein Subunits
Rats
Rats, Sprague-Dawley
Receptors, AMPA - administration & dosage
Receptors, AMPA - genetics
Receptors, AMPA - metabolism
Time Factors
Transgenes
Xenopus
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Summary:The morphology of the mature motor neuron dendritic arbor is determined by activity-dependent processes occurring during a critical period in early postnatal life. The abundance of the AMPA receptor subunit GluR1 in motor neurons is very high during this period and subsequently falls to a negligible level. To test the role of GluR1 in dendrite morphogenesis, we reintroduced GluR1 into rat motor neurons at the end of the critical period and quantitatively studied the effects on dendrite architecture. Two versions of GluR1 were studied that differed by the amino acid in the "Q/R" editing site. The amino acid occupying this site determines single-channel conductance, ionic permeability, and other essential electrophysiologic properties of the resulting receptor channels. We found large-scale remodeling of dendritic architectures in a manner depending on the amino acid occupying the Q/R editing site. Alterations in the distribution of dendritic arbor were not prevented by blocking NMDA receptors. These observations suggest that the expression of GluR1 in motor neurons modulates a component of the molecular substrate of activity-dependent dendrite morphogenesis. The control of these events relies on subunit-specific properties of AMPA receptors.
ISSN:0270-6474
1529-2401
DOI:10.1523/jneurosci.22-18-08042.2002