학술논문

IGF-1 Receptor Differentially Regulates Spontaneous and Evoked Transmission via Mitochondria at Hippocampal Synapses.
Document Type
Article
Source
Neuron. Feb2016, Vol. 89 Issue 3, p583-597. 15p.
Subject
*NEURAL transmission
*HIPPOCAMPUS physiology
*EVOKED potentials (Electrophysiology)
*SOMATOMEDIN C
*MITOCHONDRIAL physiology
*SYNAPSES
Language
ISSN
0896-6273
Abstract
Summary The insulin-like growth factor-1 receptor (IGF-1R) signaling is a key regulator of lifespan, growth, and development. While reduced IGF-1R signaling delays aging and Alzheimer’s disease progression, whether and how it regulates information processing at central synapses remains elusive. Here, we show that presynaptic IGF-1Rs are basally active, regulating synaptic vesicle release and short-term plasticity in excitatory hippocampal neurons. Acute IGF-1R blockade or transient knockdown suppresses spike-evoked synaptic transmission and presynaptic cytosolic Ca 2+ transients, while promoting spontaneous transmission and resting Ca 2+ level. This dual effect on transmitter release is mediated by mitochondria that attenuate Ca 2+ buffering in the absence of spikes and decrease ATP production during spiking activity. We conclude that the mitochondria, activated by IGF-1R signaling, constitute a critical regulator of information processing in hippocampal neurons by maintaining evoked-to-spontaneous transmission ratio, while constraining synaptic facilitation at high frequencies. Excessive IGF-1R tone may contribute to hippocampal hyperactivity associated with Alzheimer’s disease. Video Abstract [ABSTRACT FROM AUTHOR]