Scientists from Columbia University (USA) in experiments on Drosophila (fruit flies) found that serotonin is a chemical substance that causes the body to respond to fright - an automatic reflex in which the body freezes momentarily in response to a potential threat.
These results offer a broader understanding of the biology of the fright reaction, a poorly understood phenomenon that occurs in almost every animal, including humans.
“Based on this study, it becomes clear that the rapid release of serotonin in the Drosophila nervous system causes an initial fading,” commented author Richard Mann. “And since people also have serotonin, the results shed light on what happens when we freeze.”
In the brain, serotonin is most closely associated with the regulation of mood and emotions. But previous animal studies have shown that it also affects the speed of the animal. In this paper, it was important to understand exactly how this happens.
The team, using a special FlyWalker apparatus, analyzed the steps of a fruit fly on a special glass. Scientists have altered the levels of serotonin and dopamine in the fly’s ventral nerve channel, which is similar to the vertebral spinal cord. As a result of the experiment, it turned out that when fly neurons are activated and serotonin is secreted, the movement of the flies slows down. Whereas the "silence" of these same neurons accelerates the movement of flies. Additional experiments have shown that serotonin levels can affect insect walking speed under different conditions.
Scientists believe that a pause during fading is important - it allows the nervous system to collect information about a sudden change in the environment and decide how to respond.
Although the results of the experiment are specific for fruit flies, the widespread distribution of serotonin and the reaction to fright provide information about the chemical and molecular processes that occur during a sharp change in environment in animals and humans.