Abstract
Many types of neurons can release endocannabinoids that act as retrograde signals to inhibit neurotransmitter release from presynaptic terminals. Little is known, however, about the properties or role of such inhibition under physiological conditions. Here we report that brief bursts of presynaptic activity evoked endocannabinoid release, which strongly inhibited parallel fiber-to-Purkinje cell synapses in rat cerebellar slices. This retrograde inhibition was triggered by activation of either postsynaptic metabotropic or ionotropic glutamate receptors and was restricted to synapses activated with high-frequency bursts. Thus, endocannabinoids allow neurons to inhibit specific synaptic inputs in response to a burst, thereby dynamically fine-tuning the properties of synaptic integration.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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Benzoxazines
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Calcium Channel Blockers / pharmacology
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Calcium Channels / drug effects
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Calcium Channels / physiology
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Calcium Signaling / drug effects
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Calcium Signaling / physiology
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Cannabinoid Receptor Modulators / metabolism*
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Dendrites / drug effects
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Dendrites / metabolism
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Electric Stimulation
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Excitatory Amino Acid Antagonists / pharmacology
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Excitatory Postsynaptic Potentials / drug effects
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Excitatory Postsynaptic Potentials / physiology
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Morpholines / pharmacology
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Naphthalenes / pharmacology
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Neural Inhibition / drug effects
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Neural Inhibition / physiology*
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Organ Culture Techniques
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Piperidines / pharmacology
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Presynaptic Terminals / physiology*
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Purkinje Cells / drug effects
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Purkinje Cells / metabolism*
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Pyrazoles / pharmacology
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Rats
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Rats, Sprague-Dawley
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Receptors, AMPA / antagonists & inhibitors
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Receptors, AMPA / physiology
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Receptors, Metabotropic Glutamate / antagonists & inhibitors
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Receptors, Metabotropic Glutamate / physiology
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Synaptic Transmission / drug effects
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Synaptic Transmission / physiology*
Substances
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Benzoxazines
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Calcium Channel Blockers
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Calcium Channels
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Cannabinoid Receptor Modulators
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Excitatory Amino Acid Antagonists
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Morpholines
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Naphthalenes
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Piperidines
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Pyrazoles
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Receptors, AMPA
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Receptors, Metabotropic Glutamate
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metabotropic glutamate receptor type 1
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AM 251
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(3R)-((2,3-dihydro-5-methyl-3-((4-morpholinyl)methyl)pyrrolo-(1,2,3-de)-1,4-benzoxazin-6-yl)(1-naphthalenyl))methanone