PT  - JOURNAL ARTICLE
AU  - Ruifa Mi
AU  - Xiaopei Tang
AU  - Ralph Sutter
AU  - Desheng Xu
AU  - Paul Worley
AU  - Richard J. O'Brien
TI  - Differing Mechanisms for Glutamate Receptor Aggregation on Dendritic Spines and Shafts in Cultured Hippocampal Neurons
AID  - 10.1523/JNEUROSCI.22-17-07606.2002
DP  - 2002 Sep 01
TA  - The Journal of Neuroscience
PG  - 7606--7616
VI  - 22
IP  - 17
4099  - http://www.jneurosci.org/content/22/17/7606.short
4100  - http://www.jneurosci.org/content/22/17/7606.full
SO  - J. Neurosci.2002 Sep 01; 22
AB  - We have explored the ability of axons from spinal and hippocampal neurons to aggregate NMDA- and AMPA-type glutamate receptors on each other as a way of exploring the molecular differences between their presynaptic elements. Spinal axons, which normally cluster only AMPA-type glutamate receptors on other spinal neurons, cluster both AMPA- and NMDA-type glutamate receptors on the dendritic shafts of hippocampal interneurons but are ineffective at clustering either subtype of glutamate receptor on the dendritic spines of hippocampal pyramidal neurons. Conversely, hippocampal axons appear to be multipotent, capable of clustering both AMPA- and NMDA-type glutamate receptors on hippocampal interneurons and pyramidal cells. The secretion of the neuronal activity-regulated pentraxin (Narp) by hippocampal axons is restricted to contacts with interneurons. Exogenous application of Narp to cultured hippocampal neurons results in clusters of both NMDA- and AMPA-type glutamate receptors on hippocampal interneurons but not hippocampal pyramidal neurons. Because Narp displays no ability to directly aggregate NMDA receptors, we propose that Narp aggregates NMDA receptors in hippocampal interneurons indirectly through cytoplasmic coupling to synaptic AMPA receptors. Furthermore, our data suggest the existence of a novel molecule(s), capable of forming excitatory synapses on dendritic spines.