Scientists reveal how the brain may fuel intense neural communication
Results suggest retrieval of cellular powerplants via an energy feedback
loop sustains communication

Date:
October 5, 2020
Source:
NIH/National Institute of Neurological Disorders and Stroke
Summary:
In an in-depth study of neurons grown in laboratory petri dishes,
researchers discovered how neuronal synapses find the energy to
support intense communications bouts thought to underlie learning
and memory.



FULL STORY ==========================================================================
Our thoughts, feelings, and movements are controlled by billions of
neurons talking to each other at trillions of specialized communication
points called synapses. In an in-depth study of neurons grown in
laboratory petri dishes, National Institutes of Health researchers
discovered how the chattiest of some synapses find the energy to support intense conversations thought to underlie learning and memory. Their
results, published in Nature Metabolism, suggest that a series of chemical reactions control a feedback loop that senses the need for more energy and replenishes it by recruiting cellular powerplants, called mitochondria,
to the synapses. The experiments were performed by researchers in a
lab led by Zu-Hang Sheng, Ph.D., at the NIH's National Institute of Neurological Disorders and Stroke (NINDS).


==========================================================================
The team studied synapses that use the neurotransmitter glutamate
to communicate. Communication happens when a packet of glutamate is
released from presynaptic boutons which are tiny protrusions that stick
out, like beads on a string, of long, wiry parts of neurons called
axons. Previously, Dr. Sheng's team showed that synaptic communication
is an energy-demanding process and that mitochondria traveling along
axons can control signals sent by boutons. Boutons that had mitochondria
sent stronger and more consistent signals than those that were missing powerplants. The difference was due to higher energy levels produced by
the mitochondria in the form of ATP.

In this study, led by Sunan Li, Ph.D., a post-doctoral fellow at
NINDS, the team investigated what happens when boutons undergo intense communication thought to underlie learning and memory. They found that
this type of signaling quickly dropped energy levels at boutons. These
changes triggered a series of chemical reactions controlled by an energy
sensor called AMP-activated protein kinases (AMPK) that ultimately led
to the rapid recruitment of mitochondria to the boutons. Genetically
blocking or chemically interfering with this feedback loop prevented the delivery of mitochondria to boutons and lowered energy levels. This,
in turn, reduced synaptic responses during intense communication more
than seen in control cells and slowed the recovery of the responses after
the bursts ended. The researchers concluded that this feedback loop may normally play a critical role in providing the energy needed to sustain synaptic communication throughout a healthy nervous system. For example,
they cite studies which implied that problems with this system may occur
in some cases of Alzheimer's disease and other neurological disorders.


========================================================================== Story Source: Materials provided by NIH/National_Institute_of_Neurological_Disorders_and Stroke. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Li, S. et al. The crosstalk of energy sensing and mitochondrial
anchoring
sustains synaptic efficacy by maintaining presynaptic
metabolism. Nature Metabolism, 2020 DOI: 10.1038/s42255-020-00289-0 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/10/201005122136.htm

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