Chinese scientists from a team led by HUANG Yanyi and CHEN Xian (Institute of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology) have developed a new fluorescent probe to detect the neurotransmitter — serotonin — in live cells. This study is the first to reveal a new intermediate mechanism for depression and could help lead to better treatments for it.
Decoding the Mystery of Serotonin
The relationship between serotonin and depression has been controversial in the scientific community for many years. The conventional wisdom is that depression is the result of low serotonin, but science just doesn´t back this up as powerfully as previously thought.
Now, in a step closer to elucidating this complex interplay, scientists from Guangxi University, China have engineered an ultra-highly sensitive and selective fluorescent probe that traps serotonin dynamics inside cells. With this new tool, the researchers have discovered some unexpected perspectives on how serotonin contributes to depression susceptibility and symptoms.
When the team utilized this probe, it showed that ‘depressive’ and normal cells have strikingly comparable levels of serotonin. But depressive cells, he found, were much less capable of releasing serotonin in response to stimulation. This goes against the conventional wisdom that more serotonin equals less depression.
Unlocking the Secrets of mTOR
Further investigations uncovered an intriguing relationship between the brain’s capability to release serotonin and another biomolecule named mTOR (mechanistic target of rapamycin) in neurons. As mTOR has also been implicated in several cellular signaling pathways, this finding could reveal a new and profound role for mTOR in the regulation of serotonin release.
The depression cells showed a significant increase in serotonin release when mTOR activation was added, and inhibition of mTOR suppressed serotonin release in normal cells. These findings indicate that both mTOR activity and serotonin release are impaired in depression, with mTOR dysregulation being a likely contributing factor to these impairments.
The discovery opens up new avenues for the creation of antidepressants that act more selectively and effectively. Through understanding the regulation of mTOR (as well as serotonin release) instead of just focusing on the levels, it may be possible to generate new therapeutic paradigms that treat at their core this life-altering disorder.
Conclusion
The generation of a fluorescent probe like this opens up an incredibly important new avenue for researchers to explore the multifaceted interplays between brain chemistry and mental ill-health. The study is a call for the re-examination of the conventional perspective on serotonin as related to SIB, and should force clinical consideration, treatment options and drug development endeavours toward a more refined and holistic direction. The findings of this research has the potential to completely change how we think about and treat depression — a major public health concern.
