Changes in splice variant expression and subunit assembly of AMPA receptors during maturation of hippocampal astrocytes.
Astrocytes in the hippocampus express glutamate receptors of the AMPA subtype. An increasing body of evidence suggests a contribution of astroglial AMPA receptors to a direct signaling between neurons and glial cells in vivo. Here, we have combined functional analysis with singlecell RT-PCR to investigate whether hippocampal astrocytes express Ca(2+)-permeable AMPA receptors. We show that by postnatal day 5, a mosaic of Ca(2+)-permeable and less Ca(2+)-permeable AMPA receptors coexists in individual astrocytes, while receptors with a more uniform, low divalent permeability dominate in older cells. Moreover, we report an upregulation of the flip form of the GluR2 subunit during maturation, while the splicing status of GluR1 and GluR4 remains unchanged. Due to its specific properties, Ca(2+)-permeable AMPA receptors in astrocytes might strengthen neuron-to-glia signaling and enable proper formation of structural and functional connections between glial cells and glutamatergic synapses in the developing hippocampus.
Seifert
Gerald
G
Experimental Neurobiology, Neurosurgery, Bonn University, Sigmund-Freud-Str. 25, 53105, Bonn, Germany. gerald.seifert@ukb.uni-bonn.de
Weber
Marco
M
Schramm
Johannes
J
Steinhäuser
Christian
C
D017398:Alternative Splicing / Q000235:genetics; D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000378:metabolism* / Q000648:ultrastructure; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000502:physiology; D002450:Cell Communication / Q000235:genetics; D002454:Cell Differentiation / Q000502:physiology*; D002462:Cell Membrane / Q000378:metabolism* / Q000648:ultrastructure; D002478:Cells, Cultured; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000235:genetics; D018698:Glutamic Acid / Q000378:metabolism / Q000494:pharmacology; D006624:Hippocampus / Q000254:growth & development* / Q000378:metabolism / Q000648:ultrastructure; D008564:Membrane Potentials / Q000187:drug effects / Q000235:genetics; D051379:Mice; D009474:Neurons / Q000378:metabolism; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D018091:Receptors, AMPA / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics; D013096:Spermine / Q000494:pharmacology; D013111:Spider Venoms / Q000494:pharmacology; D009435:Synaptic Transmission / Q000235:genetics
D002118:Calcium; D018698:Glutamic Acid; D020033:Protein Isoforms; D018091:Receptors, AMPA; D013096:Spermine; D013111:Spider Venoms; C044936:JSTX spider toxin; C104724:glutamate receptor ionotropic, AMPA 4; C104722:glutamate receptor ionotropic, AMPA 2