Drug addicts are more likely to carry an ancient virus which could affect the production of dopamine than the rest of the population, a study has found.
Scientists studied a type of ancient retrovirus called HERV-K HML-2 (HK2). A retrovirus is a form of bug which transcribes its RNA into the DNA of a host cell to multiply. Retroviruses can either spread exogenously between individuals, like HIV, or endogenously from parents to offspring, but they were not previously believed to be harmful in humans.
[T]his type of HK2 can manipulate neighboring genes, including one which plays a role in how dopamine is released in the brain. Dopamine is a neurotransmitter connected to rewarding experiences, and is therefore implicated in addiction.
“We show the strongest evidence provided to date that an endogenous retrovirus is linked to harmful effects in humans, by showing a link between an integrated retrovirus and addictive behavior,” [says researcher Aris Katzourakis.]
To conduct their study, the researchers in Greece recruited 202 HIV positive participants, and found RASGRF2 was 2.5 times more common in patients who were infected via intravenous drugs than those who were infected by other means. And in a separate part of the study conducted in the U.K., 184 hepatitis C patients were 3.6 times more likely to have RASGRF2 in their genes if they had suffered chronic drug abuse.
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