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April 2015 | Read this issue and more at www.healthandwellnessmagazine.net |
Exercise May Prevent
and Treat Depression
Research shows enzyme
purges harmful substances
By Angela S. Hoover, Staff Writer
Swedish
researchers at the
Karolinska
Institutet medical university have discovered how
exercise protects against stressinduced depression. Scientists have
known that during exercise there is
an increase of a protein called PGC1a1 in skeletal muscle. Their initial
hypothesis was that trained muscle
would produce a substance with ben-
eficial effects on the brain, but they
discovered the opposite. Well-trained
muscle produces an enzyme that
purges harmful substances from the
body, likening the muscle’s function
to that of the kidney or liver, according to the principal investigator Jorge
Ruas.
Genetically modified mice with
elevated levels of PGC-1a1 in their
skeletal muscle and normal mice were
exposed to a stressful environment in
the lab. The stressors were loud music
and flashing lights; the mice also had
their circadian rhythm reversed at
irregular intervals. After five weeks,
the normal mice developed symptoms of depression, but the genetically modified mice displayed no
depressive symptoms. The researchers further learned the genetically
modified mice had higher levels of
KAT enzymes in addition to the high
levels of PGC-1a1. KAT enzymes
convert kynurenine, a substance
formed during stress, into kynurenic
acid. Kynurenic acid cannot pass
from the blood to the brain.
Normal mice given kynurenine
developed depression, but the behavior of the PGC-1a1 mice was unaffected by kynurenine. Furthermore,
their blood did not show raised
levels of kynurenine. The researchers learned this was because the
KAT enzymes in the trained muscles
were able to convert kynurenine into
kynurenic acid more quickly. The
researchers think this quick conver-
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sion process is the protective mechanism. They also believe these findings
open the door for future pharmacological research that aims to influence
skeletal muscle function, rather than
drugs that target the brain directly.
“Skeletal muscle appears to have
a detoxification effect that, when
activated, can protect the brain
from insults and related mental illness,” Ruas said. The research was
published in the journal Cell last
September.
In 2013, UK researchers updated
their systematic review by analyzing 35 randomized controlled trials
involving 1,356 patients diagnosed
with depression. They found exercising was as beneficial as psychological
therapy or taking antidepressants.
However, they caution these findings
were based on only a small number
of low-quality trials and that larger,
higher-quality trials are needed.
Exercise induces
changes in the
skeletal muscle that
can purge the blood
of a substance that
accumulates during
stress and is harmful
to the brain.