Synaptic activation of a presynaptic kainate receptor facilitates AMPA receptor-mediated synaptic transmission at hippocampal mossy fibre synapses.
The development of GluR5-selective kainate receptor ligands is helping to elucidate the functions of kainate receptors in the CNS. Here we have further characterised the actions of a GluR5 selective agonist, ATPA, and a GluR5 selective antagonist, LY382884, in the CA3 region of rat hippocampal slices. In addition, we have used LY382884 to study a novel synaptic mechanism. This antagonist substantially reduces frequency facilitation of mossy fibre synaptic transmission, monitored as either AMPA or NMDA receptor-mediated EPSCs. This suggests that GluR5-containing kainate receptors on mossy fibres function as autoreceptors to facilitate the synaptic release of L-glutamate, in a frequency-dependent manner.
Lauri
S E
SE
MRC Centre for Synaptic Plasticity, Department of Anatomy, Medical School, University of Bristol, BS8 1TD, Bristol, UK.
Delany
C
C
J  Clarke
V R
VR
Bortolotto
Z A
ZA
Ornstein
P L
PL
T R  Isaac
J
J
Collingridge
G L
GL
D000818:Animals; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D066298:In Vitro Techniques; D007555:Isoxazoles / Q000494:pharmacology; D019599:Mossy Fibers, Hippocampal / Q000187:drug effects / Q000502:physiology*; D011422:Propionates / Q000494:pharmacology; D051381:Rats; D018091:Receptors, AMPA / Q000502:physiology*; D018092:Kainic Acid Receptors / Q000819:agonists / Q000037:antagonists & inhibitors / Q000502:physiology*; D017661:Receptors, Presynaptic / Q000819:agonists / Q000037:antagonists & inhibitors / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013569:Synapses / Q000187:drug effects / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*
D018690:Excitatory Amino Acid Agonists; D007555:Isoxazoles; D011422:Propionates; D018091:Receptors, AMPA; D018092:Kainic Acid Receptors; D017661:Receptors, Presynaptic; C081662:alpha-amino-3-hydroxy-5-tert-butyl-4-isoxazolepropionate