MDMA and the effect on serotonin and oxytocin - Research in zebrafish

MDMA is a substance known for its unique effect on feelings of trust, connection, and openness. During therapeutic sessions, we often see that people can express themselves more easily, feel safe, and are able to allow deep emotions. But what actually happens in the brain when someone uses MDMA?

A new scientific study offers interesting insights. Zebrafish were used in this study. These small aquatic animals are often employed in neuroscience due to their strong similarities to human brain processes regarding neurotransmitters, stress, and social behavior. Using these fish, researchers investigated the effects of MDMA on behavioral levels as well as on gene activity in the brain.

What stood out was that zebrafish given a low dose of MDMA became noticeably more social. They swam towards their conspecifics more often, sought contact, and appeared less shy. At slightly higher doses, they also dared to move more freely in open and well-lit spaces, indicating a decrease in fearful behavior. Conversely, at excessively high doses, disturbances occurred in the fish's motor functioning. This demonstrates how important it is to handle MDMA dosage carefully. The balance is subtle, and the therapeutic value appears to be greatest at low to moderate doses.

The most impressive part of this study was not only the visible behavior of the zebrafish, but especially what was happening in the brain. The scientists discovered that MDMA actually changes the way brain cells receive and process signals. For instance, it turned out that the genes encoding serotonin receptors and the associated transport proteins became less active. This is in line with what we already knew: MDMA causes a temporary release of large amounts of serotonin in the brain, which can induce a sense of well-being and relaxation. At the same time, the researchers observed that sensitivity to oxytocin increased because the number of oxytocin receptors rose. This means that the brain becomes more receptive to feelings of closeness, bonding, and love.

Interestingly enough, it also turned out that the number of vasopressin receptors actually decreased. Vasopressin is a substance typically linked to distance, alertness, and sometimes even hostility. The combination of these changes suggests that MDMA puts the brain in a state of social openness and safety. That is exactly what many people experience during a good guided therapeutic session with MDMA.