Kainate receptors differentially regulate release at two parallel fiber synapses.
Presynaptic kainate receptors (KARs) facilitate or depress transmitter release at several synapses in the CNS. Here, we report that synaptically activated KARs presynaptically facilitate and depress transmission at parallel fiber synapses in the cerebellar cortex. Low-frequency stimulation of parallel fibers facilitates synapses onto both stellate cells and Purkinje cells, whereas high-frequency stimulation depresses stellate cell synapses but continues to facilitate Purkinje cell synapses. These effects are mimicked by exogenous KAR agonists and eliminated by blocking KARs. This differential frequency-dependent sensitivity of these two synapses regulates the balance of excitatory and inhibitory input to Purkinje cells and therefore their excitability.
Delaney
Andrew J
AJ
Vollum Institute, Oregon Health and Science University, L474, Portland, OR 97201, USA.
Jahr
Craig E
CE
D027322:Amino Acid Transport System X-AG / Q000037:antagonists & inhibitors / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology*; D018756:GABA Antagonists / Q000494:pharmacology; D018698:Glutamic Acid / Q000378:metabolism; D007608:Kainic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology*; D009467:Neuromuscular Depolarizing Agents / Q000494:pharmacology; D009924:Organ Culture Techniques; D017729:Presynaptic Terminals / Q000187:drug effects / Q000378:metabolism*; D011689:Purkinje Cells / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D018080:Receptors, GABA-B / Q000187:drug effects / Q000378:metabolism; D018092:Kainic Acid Receptors / Q000187:drug effects / Q000378:metabolism*; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects / Q000378:metabolism; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*
D027322:Amino Acid Transport System X-AG; D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists; D018756:GABA Antagonists; D018698:Glutamic Acid; D007608:Kainic Acid; D009467:Neuromuscular Depolarizing Agents; D018080:Receptors, GABA-B; D018092:Kainic Acid Receptors; D016194:Receptors, N-Methyl-D-Aspartate; C012301:domoic acid