Distinct micro-opioid ensembles trigger positive and negative fentanyl reinforcement. (https://pubmed.ncbi.nlm.nih.gov/38778097/)

These scientists wanted to understand how a powerful painkiller called fentanyl can lead to addiction in some people. They did an experiment using mice to see how fentanyl affects certain parts of the brain.

First, they injected mice with fentanyl to see how it changes the activity of certain neurons in the brain. They found that fentanyl can make some neurons in the brain release more dopamine, a chemical that makes us feel good. This increased dopamine can lead to positive feelings that make people want to take fentanyl again.

The scientists also discovered that fentanyl can affect another part of the brain that controls negative feelings. When they blocked certain receptors in this part of the brain, the mice didn't feel as bad when they were going through withdrawal from fentanyl.

By understanding how fentanyl affects different parts of the brain, the scientists hope to find ways to help people who are addicted to fentanyl and to develop treatments to help them recover.

Chaudun F., Python L., Liu Y., Hiver A., Cand J., Kieffer BL., Valjent E., Luscher C. Distinct micro-opioid ensembles trigger positive and negative fentanyl reinforcement. Nature. 2024 May 22. doi: 10.1038/s41586-024-07440-x.