Serotonin is a key player in depression, impacting diagnosis, treatment, and drug development. A Chinese research team has developed a fluorescent probe that is highly sensitive and selective towards serotonin, allowing for better understanding of processes involved in depression. While serotonin levels have traditionally been linked to depression, recent studies have shown that other factors may also contribute to the condition. The team, led by Weiying Lin at Guangxi University, designed a reactive group that can specifically react with serotonin, allowing for precise detection of the molecule in cell and animal models.
The team’s fluorescent probe utilizes a reactive building block that selectively binds to serotonin, triggering a cascade reaction that ultimately switches on the fluorescence of the dye attached to it. This allows for the sensitive detection of serotonin, even within cells. By using this probe, the team was able to image neuron cells that can be used as a model for depression. Surprisingly, the serotonin levels in normal and “depressed” cells were found to be similar, with the difference lying in the cells’ ability to expel serotonin in response to stimulation.
Further investigation revealed a potential link between the activity of the biomolecule mTOR and the cells’ ability to release serotonin. Activation of mTOR led to increased serotonin release in the “depressed” cells, while inhibition of mTOR reduced serotonin release in normal cells. These findings were consistent across neuron and mouse models, suggesting that the ability of neurons to release serotonin may play a more significant role in depression than the actual levels of serotonin present.
The results of the imaging studies challenge the conventional belief that serotonin levels are the primary factor in depression. Instead, the team’s findings suggest that the ability of neurons to release serotonin, influenced by mTOR activity, is a crucial aspect of the condition. This discovery could pave the way for new advancements in the treatment of depression, potentially leading to more targeted and effective therapeutic approaches. Through their innovative probe and imaging studies, the Chinese research team has provided valuable insights into the complex interplay between serotonin, mTOR, and depression, opening up new avenues for further research and treatment development in this challenging area of mental health.