Team discovers
possible
“Universal Strategy” to combat addiction
Newswise — An
international research team led by the University of
Saskatchewan has discovered a signaling pathway in the
brain involved in drug addiction, together with a method
for blocking its action, that may point to a single
treatment strategy for most addictions.
Their findings appear
in the March issue of the prestigious journal Nature
Medicine.
The team, led by Xia
Zhang, associate professor in the U of S department of
psychiatry, found that a naturally occurring enzyme
known as PTEN acts on the part of the brain where many
drugs of abuse exert their rewarding effects - the
ventral tegmental area (VTA)
“Our results suggest a
potential universal strategy for treating drug
addiction,” Zhang says. “Most drugs of abuse act on the
neurons in this area.”
He cautions that much
work remains to be done before a treatment based on the
discovery could be developed to help drug addicts. This
includes several years of further testing, including
animal and, finally, human trials.
“We have our peptide,
but there’s a long way to go before a clinical
application,” he says.
“Dr. Zhang’s research
is important to our understanding of drug addiction. His
work epitomizes how health research holds the key to
improved health and quality of life for Canadians and
people throughout the world,” said Dr. Rémi Quirion,
Scientific Director of the Canadian Institutes of Health
Research Institute of Neurosciences, Mental Health and
Addiction.
Zhang, who worked with
colleagues at the U of S, University of Toronto, and
Vanderbilt University in Tennessee on the project,
explains that VTA brain cells are sensitive to
serotonin, a hormone associated with learning, sleep and
mood. The team discovered that PTEN acts on these
serotonin receptors, increasing brain cell activity.
This is the same “reward” process sparked by drugs of
abuse.
Armed with this
knowledge, the team designed a molecule called a
peptide, tailored to fit the serotonin receptors and
block PTEN. When rats were treated with this PTEN-blocker,
it shut down the drug reward process – including the
process that induces craving and withdrawal.
The study, funded by
the Canadian Institutes of Health Research and the
Natural Sciences and Engineering Research Council,
looked at nicotine and THC (the active ingredient in
marijuana). However, Zhang says the results could also
hold true for other drugs such as cocaine, heroin, and
even methamphetamine.
Zhang’s U of S
research team is part of the Neural Systems and
Plasticity Research Group, one of several
interdisciplinary health sciences research groups at the
University. The group, dedicated to the study of brain
systems and how they change with experience, draws
expertise from numerous departments across six colleges
on campus.
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