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Autophagy. 2012 Oct;8(10):1540-1. doi: 10.4161/auto.21330. Epub 2012 Jul 6.

Macroautophagy can press a brake on presynaptic neurotransmission.

Author information

1
Integrated Program in Cellular, Molecular and Biomedical Studies, Columbia University Medical Center, New York, NY, USA.

Abstract

The mechanistic target of rapamycin (MTOR) has been implicated in regulating synaptic plasticity and neurodegeneration, but MTOR's role in modulating presynaptic function through autophagy is unexplored. We studied presynaptic function in ventral dopamine neurons, a system from which neurotransmitter release can be measured directly by cyclic voltammetry. We generated mutant mice that were specifically deficient for macroautophagy in dopaminergic neurons by deleting the Atg7 gene in cells that express the dopamine uptake transporter. Dopamine axonal profiles in the mutant dorsal striatum were ~one third larger in the mutant mice, released ~50% more stimulus-evoked dopamine release, and exhibited more rapid presynaptic recovery than controls. Rapamycin reduced dopamine neuron axon profile size by ~30% in control mice, but had no effect on macroautophagy deficient axons. Acute rapamycin decreased dopaminergic synaptic vesicle density by ~25% and inhibited evoked dopamine release by ~25% in control mice, but not in the Atg7 deficient mutants. Thus, both basal and induced macroautophagy can provide a brake on presynaptic activity in vivo, perhaps by regulating the turnover of synaptic vesicles, and further regulates terminal volume and the kinetics of transmitter release.

PMID:
22767262
PMCID:
PMC3463456
DOI:
10.4161/auto.21330
[Indexed for MEDLINE]
Free PMC Article

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