Scientists at Tokyo Metropolitan University have uncovered a key part of the biochemical pathway linking stress and sexual dysfunction. By studying the fruit fly Drosophila melanogaster, they showed that the neurotransmitter dopamine determines how long male flies exhibit sustained courtship inhibition after being confined to a small space, but not whether mating is inhibited in the first place. Their discoveries in key model organisms reveal the neurobiological factors that drive sexual dysfunction in other organisms, including humans.
The biochemistry of stress is an important but poorly understood aspect of neurobiology. Exposure to internal or external stimuli is known to cause changes in the brain that continue to affect the organism far beyond the duration of the changes. An example is how stress affects sexual behavior. It is known that people who suffer from post-traumatic stress disorder often exhibit sexual dysfunction. However, despite solid evidence, the molecular mechanisms by which stress causes decreased sexual desire are still not understood.
A team led by Professor Takaomi Sakai of Tokyo Metropolitan University is using fruit flies to study the relationship between stress and behavioral changes. Drosophila is an important ‘model organism’, with its biochemical pathways sufficiently similar to a wide range of animals, including mammals, to be able to reveal important aspects of its function, while at the same time being much easier to study. The research team investigated how “confined space” stress, the effect of placing male fruit flies in a confined space, led to suppression of courtship behavior. Although confinement stress is known to affect many organisms, this was the first time it had been applied to research in Drosophila.
The researchers found that the duration of stress in male flies affected the duration of suppressed courtship behavior. Flies trapped for 10 min showed no inhibition, whereas flies trapped for 30 or 60 min showed clearly inhibited courtship behavior. The longer the flies were stressed, the longer the effects lasted. In fact, people exposed to 7 or 24 hours of stress showed courtship inhibition for at least 5 days. Curiously, this was not simply due to decreased mobility or appetite.
To trace the biochemical origins of this phenomenon, they investigated dopamine, a neurotransmitter known to be involved in responses to stress. Studies of fruit flies in which dopamine production has been suppressed either genetically or pharmacologically found no difference in whether courtship inhibition occurred in either case. However, it had a significant impact on whether the stress-induced response persisted. Therefore, dopamine is especially sustainability Changes in behavior caused by stress. Researchers traced this effect to the mushroom body, a part of the brain associated with sensory processing, where specific dopamine receptors were found to mediate the maintenance of stress-induced behaviors.
The research team’s findings reveal a specific role for dopamine in mediating the effects of stress on sexual dysfunction. This is important evidence for elucidating how stress affects the behavior and health of other living things, including humans.
sauce:
Tokyo Metropolitan University
Reference magazines:
Tetsuya Sato Others. (2026). Role of dopamine signaling in confinement stress-induced male courtship inhibition in Drosophila melanogaster. iscience. DOI: 10.1016/j.isci.2026.115906. https://www.sciencedirect.com/science/article/pii/S2589004226012812?via%3Dihub
