The addictive effect of fentanyl is controlled by two brain regions
Published: Wednesday, May 22nd 2024, 17:20
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Two different circuits in the brain are responsible for the addictive effect of fentanyl. This finding by researchers in Geneva could help in the treatment of opioid addiction and in the production of drugs with fewer side effects.
"What we have found changes the understanding of opioid addiction," said study leader Christian Lüscher on Wednesday at the request of the Keystone-SDA news agency.
The opioid fentanyl is a powerful painkiller. However, it is also frequently abused as a drug. In the USA, it is responsible for three quarters of all overdose deaths, as the University of Geneva writes in a press release. "Fentanyl is incredibly potent," emphasized Lüscher. It only takes a fraction of a gram to achieve the desired effect. Compared to heroin, it is around 20 to 40 times stronger.
Despite the damage caused by the opioid, knowledge about its effect on the brain is incomplete. For the study now published in the journal "Nature", Lüscher and French colleagues therefore administered fentanyl to mice and examined what happens in their brains.
Various circuits
Like other opioids, fentanyl causes strong euphoric effects when it is taken. If it is then no longer taken, withdrawal effects can occur. Scientists refer to this as positive and negative reinforcement. Until now, researchers had assumed that these two effects take place in the same region of the brain.
The study has now shown that positive reinforcement takes place in the so-called mesolimbic system of the brain. Negative reinforcement, on the other hand, activates a different brain region. According to the University of Geneva, this is a previously unknown cell population located in the brain region of the central amygdala, which is associated with fear and anxiety.
According to the University of Geneva, the knowledge that these two effects run through two different circuits explains why substances such as fentanyl have a particularly high addictive potential, as the two mechanisms add up.
According to Lüscher, the results could also potentially help to develop painkillers that are less addictive.
©Keystone/SDA
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