Abstract
Synapses that reliably activate their postsynaptic targets typically release neurotransmitter with high probability, are not very sensitive to changes in calcium entry, and depress. We have determined the mechanisms that give rise to these characteristic features at the climbing fiber to Purkinje cell synapse. We find that saturation of presynaptic calcium entry, of presynaptic release, and of postsynaptic receptors combine to produce a postsynaptic response that is near maximal. Postsynaptic receptor saturation also accelerates recovery from depression, in part by accentuating a rapid calcium-dependent recovery phase. Thus, postsynaptic receptor saturation interacts with presynaptic mechanisms to produce highly reliable synapses that can effectively drive their targets even during sustained activation.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Action Potentials / drug effects
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Action Potentials / physiology
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Animals
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Animals, Newborn
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Calcium / pharmacology
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Calcium Signaling / drug effects
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Calcium Signaling / physiology
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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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Long-Term Synaptic Depression / drug effects
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Long-Term Synaptic Depression / physiology
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Neural Pathways / drug effects
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Neural Pathways / physiology*
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Neuronal Plasticity / drug effects
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Neuronal Plasticity / physiology
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Olivary Nucleus / drug effects
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Olivary Nucleus / physiology*
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Presynaptic Terminals / drug effects
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Presynaptic Terminals / physiology*
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Purkinje Cells / drug effects
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Purkinje Cells / physiology*
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Rats
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Rats, Sprague-Dawley
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Receptors, AMPA / drug effects
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Receptors, AMPA / physiology
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Receptors, Neurotransmitter / drug effects
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Receptors, Neurotransmitter / physiology*
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Synaptic Membranes / drug effects
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Synaptic Membranes / physiology*
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Synaptic Transmission / drug effects
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Synaptic Transmission / physiology*
Substances
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Excitatory Amino Acid Antagonists
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Receptors, AMPA
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Receptors, Neurotransmitter
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Calcium