Abstract
Using a novel approach to measure exocytosis in vitro from semi-intact synaptosomes, we establish that the Ca2+-dependent release of glutamate requires cytosolic factors for mobilization from the reserve pool. The cytosolic activity for glutamate release was not satisfied by CAPS, a soluble component required for norepinephrine (NE) release. Moreover, the CAPS-independent glutamate release from synaptic vesicles (SVs) was 200-fold less sensitive to Ca2+ than that required for dense core vesicles (DCVs). The differential regulation of exocytosis by CAPS, Ca2+, and potential novel cytosolic factor(s) suggests that the docking and fusion machinery controlling DCVs has diverged from that regulating glutamate-containing SVs.
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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Animals
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Caenorhabditis elegans Proteins*
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Calcium / physiology*
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Calcium-Binding Proteins*
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Cytosol / metabolism
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Cytosol / physiology
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Exocytosis / physiology*
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Glutamic Acid / metabolism
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Helminth Proteins / immunology
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Helminth Proteins / physiology*
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Male
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Membrane Proteins / physiology
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Neurotransmitter Agents / metabolism
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Rats
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Rats, Sprague-Dawley
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SNARE Proteins
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Synaptosomes / metabolism
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Synaptosomes / physiology*
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Vesicular Transport Proteins*
Substances
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Caenorhabditis elegans Proteins
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Calcium-Binding Proteins
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Helminth Proteins
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Membrane Proteins
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Neurotransmitter Agents
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SNARE Proteins
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UNC-31 protein, C elegans
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Vesicular Transport Proteins
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Glutamic Acid
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Calcium