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Vesicular zinc regulates the Ca2+ sensitivity of a subpopulation of presynaptic vesicles at hippocampal mossy fiber terminals.

Publication Type:

Journal Article

Source:

J Neurosci, Volume 31, Issue 50, p.18251-65 (2011)

Keywords:

Animals, Calcium, Excitatory Postsynaptic Potentials, Glutamic Acid, Mice, Miniature Postsynaptic Potentials, Mossy Fibers, Hippocampal, Neuronal Plasticity, Neurons, Synapses, Synaptic Vesicles, Zinc

Abstract:

Synaptic vesicles segregate into functionally diverse subpopulations within presynaptic terminals, yet there is no information about how this may occur. Here we demonstrate that a distinct subgroup of vesicles within individual glutamatergic, mossy fiber terminals contain vesicular zinc that is critical for the rapid release of a subgroup of synaptic vesicles during increased activity in mice. In particular, vesicular zinc dictates the Ca(2+) sensitivity of release during high-frequency firing. Intense synaptic activity alters the subcellular distribution of zinc in presynaptic terminals and decreases the number of zinc-containing vesicles. Zinc staining also appears in endosomes, an observation that is consistent with the preferential replenishment of zinc-enriched vesicles by bulk endocytosis. We propose that functionally diverse vesicle pools with unique membrane protein composition support different modes of transmission and are generated via distinct recycling pathways.

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