Clustering of gephyrin at GABAergic but not glutamatergic synapses in cultured rat hippocampal neurons

Ann Marie Craig, Gary Banker, Weiru Chang, Maureen E. McGrath, Anna S. Serpinskaya

Research output: Contribution to journalArticlepeer-review

147 Scopus citations

Abstract

The molecular mechanisms underlying the establishment of a postsynaptic receptor mosaic on CNS neurons are poorly understood. One protein thought to be involved is gephyrin, a peripheral membrane protein that binds to the inhibitory glycine receptor and functions in clustering this receptor at synapses in cultured rat spinal cord neurons. We investigated the possible association of gephyrin with synapses in cultured rat hippocampal neurons, where glutamate and GABA but not glycine are the principal transmitters. Gephyrin immunoreactivity was detected in axons as well as dendrites, changing from a predominantly axonal to a more dendritic distribution with time in culture. Gephyrin staining was not distributed uniformly, but always took the form of clusters. Small clusters of gephyrin (0.2 μm2), present throughout development, were distributed widely and not restricted to synaptic sites. Larger clusters of gephyrin (0.4-10.0 μm2, sometimes composed of groups of small clusters), which developed in older cells, were localized to a subset of contacts between axons and dendrites. These large clusters were not present at glutamatergic synapses (marked by immunostaining for GluR1), but were closely associated with GABAergic synapses (marked by immunostaining for GABA and glutamic acid decarboxylase). These results, together with previous findings, suggest that gephyrin may function to anchor GABA and glycine receptors, but not glutamate receptors, at postsynaptic sites on central neurons. They also raise the possibility that gephyrin has additional functions, independent of its role at synapses.

Original languageEnglish (US)
Pages (from-to)3166-3177
Number of pages12
JournalJournal of Neuroscience
Volume16
Issue number10
DOIs
StatePublished - May 15 1996
Externally publishedYes

Keywords

  • GABA receptor
  • gephyrin
  • glutamate receptor
  • hippocampal neuron
  • postsynaptic site
  • receptor clustering
  • synaptogenesis

ASJC Scopus subject areas

  • General Neuroscience

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