The silent epidemic of fentanyl which has devastated the United States, where the list of deaths caused by addiction to this opioid has not stopped increasing in recent years. 50 times stronger than heroin and 100 times more powerful than morphine, this drug has transformed into a substance present in the daily lives of many citizens consumed by the addiction that can easily be generated.
Fentanyl is a powerful synthetic opioid that, when legal in many cases, is used as a narcotic to increase dopamine levels in the central nervous system.
Easy to obtain, cheap ─each dose of fentanyl between 3 and 5 dollars─ and with immediate effect. These are the main advantages of this synthetic opioid, usually used by patients suffering from chronic pain and with tolerance to other drugs. In many cases, a medical prescription is sufficient to be able to opt for the feeling of euphoria and sedation that consumption causes.
Fentanyl can relieve pain and make us feel much more relaxed or euphoric, although the line between a medicinal and a lethal dose is very small. The problem is very interesting.
In 2022, opioids account for three-quarters of the 108,000 deaths associated with drug abuse in the United States. The opioid epidemic in EE.UU. It is a tragedy en tres actos, written in an article published in the journal ‘Nature’, by Markus Heilig and Michele Petrella, of Linköping University (Sweden).
Epidemic in three acts
He began more than 25 years of irresponsibly prescribing opioids to fuel the pain. This has led to large numbers of people becoming addicted to opioids. Eventually, the synthetic opioid fentanyl gradually replaced heroin, further increasing its mortality.
Given this public health impact, there are still surprising gaps in understanding the mechanisms by which opioids generate addiction.
Two types of effects that also promote drug use, explain them in your comment. One is the subjective feeling of reward that relates positively to drug use. If it is believed that the key to this phenomenon are the neurons that release the neurotransmitter dopamine and which are located in the ventral tegmental area (VTA) of the brain. The other effect is the feeling of nourishment when resuming drug use eliminates the bad, promoting the behavior through negative rejection. The latter is the most evident problem during withdrawal and is mediated by the generalized activation of neuronal circuits involved in the aversion or “anti-reward” system.
But how do opioids produce these effects?
Now, according to a study published in ‘Nature’, it is possible to control fentanyl addiction. The key lies in the control of two distinct neuronal pathways in the brain. This knowledge could help in the development of treatments to reduce dependence on this opioid.
Christian Lüscher’s team from the University of Geneva (Suiza) analyzed the effects of fentanyl on the brains of rats. By transferring the drug and inducing withdrawal, the brain regions active during positive and negative replenishment are identified. Fentanyl has been found to induce activity in an area of the brain where dopamine is released. By reducing the activity of μ-opioid receptors in this area, dopamine release and positive replenishment signals in rats were decreased. Furthermore, μ-opioid receptor inhibition does not alter withdrawal effects, suggesting that another pathway may mediate negative rejection. Identification of neurons with μ-opioid receptors in another brain region (the central amygdala), which shows the greatest activity during withdrawal. Deactivation of these receptors eliminated withdrawal symptoms in rats, suggesting a role in mediating negative fentanyl replenishment.
Authorities say the findings could help develop interventions and medications to reduce fentanyl dependence and aid recovery.
Heilig and Petrella suggest that hallazgos “represent a valuable advance in the scientific understanding of how opioids promote addiction.”
