Functional expression of AMPA receptors on central terminals of rat dorsal root ganglion neurons and presynaptic inhibition of glutamate release.
No direct evidence has been found for expression of functional AMPA receptors by dorsal root ganglion neurons despite immunocytochemical evidence suggesting they are present. Here we report evidence for expression of functional AMPA receptors by a subpopulation of dorsal root ganglion neurons. The AMPA receptors are most prominently located near central terminals of primary afferent fibers. AMPA and kainate receptors were detected by recording receptor-mediated depolarization of the central terminals under selective pharmacological conditions. We demonstrate that activation of presynaptic AMPA receptors by exogenous agonists causes inhibition of glutamate release from the terminals, possibly via primary afferent depolarization (PAD). These results challenge the traditional view that GABA and GABA(A) receptors exclusively mediate PAD, and indicate that PAD is also mediated by glutamate acting on presynaptically localized AMPA and kainate receptors.
Lee
C Justin
CJ
Department of Physiology and Cellular Biophysics, Columbia University, New York, New York 10032, USA.
Bardoni
Rita
R
Tong
Chi Kun
CK
Engelman
Holly Sue
HS
Joseph
Donald J
DJ
Magherini
Pier Cosimo
PC
MacDermott
Amy B
AB
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000344:Afferent Pathways / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D018756:GABA Antagonists / Q000494:pharmacology; D058787:GABA-A Receptor Antagonists; D005727:Ganglia, Spinal / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D018698:Glutamic Acid / Q000378:metabolism*; D007381:Intermediate Filament Proteins / Q000378:metabolism; D037102:Lectins; D008562:Membrane Glycoproteins; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology*; D009475:Neurons, Afferent / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D064531:Peripherins; D017729:Presynaptic Terminals / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D018091:Receptors, AMPA / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D011963:Receptors, GABA-A / Q000378:metabolism; D013126:Spinal Nerve Roots / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*
D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists; D018756:GABA Antagonists; D058787:GABA-A Receptor Antagonists; D018698:Glutamic Acid; D007381:Intermediate Filament Proteins; D037102:Lectins; D008562:Membrane Glycoproteins; D009419:Nerve Tissue Proteins; D064531:Peripherins; D018091:Receptors, AMPA; D011963:Receptors, GABA-A; C104722:glutamate receptor ionotropic, AMPA 2