Abstract
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.
Publication types
-
Research Support, Non-U.S. Gov't
-
Research Support, U.S. Gov't, P.H.S.
MeSH terms
-
Amino Acid Transport System X-AG / antagonists & inhibitors
-
Amino Acid Transport System X-AG / metabolism
-
Animals
-
Animals, Newborn
-
Excitatory Amino Acid Agonists / pharmacology
-
Excitatory Amino Acid Antagonists / pharmacology
-
Excitatory Postsynaptic Potentials / drug effects
-
Excitatory Postsynaptic Potentials / physiology*
-
GABA Antagonists / pharmacology
-
Glutamic Acid / metabolism
-
Kainic Acid / analogs & derivatives*
-
Kainic Acid / pharmacology
-
Neural Inhibition / drug effects
-
Neural Inhibition / physiology*
-
Neuromuscular Depolarizing Agents / pharmacology
-
Organ Culture Techniques
-
Presynaptic Terminals / drug effects
-
Presynaptic Terminals / metabolism*
-
Purkinje Cells / drug effects
-
Purkinje Cells / metabolism*
-
Rats
-
Receptors, GABA-B / drug effects
-
Receptors, GABA-B / metabolism
-
Receptors, Kainic Acid / drug effects
-
Receptors, Kainic Acid / metabolism*
-
Receptors, N-Methyl-D-Aspartate / drug effects
-
Receptors, N-Methyl-D-Aspartate / metabolism
-
Synaptic Transmission / drug effects
-
Synaptic Transmission / physiology*
Substances
-
Amino Acid Transport System X-AG
-
Excitatory Amino Acid Agonists
-
Excitatory Amino Acid Antagonists
-
GABA Antagonists
-
Neuromuscular Depolarizing Agents
-
Receptors, GABA-B
-
Receptors, Kainic Acid
-
Receptors, N-Methyl-D-Aspartate
-
Glutamic Acid
-
domoic acid
-
Kainic Acid