Serotonin is often identified as the neurochemical used in drugs that combat depression, but a Cornell study may have discovered more ways that the chemical may function in the brain — including changing effects depending on the situation.
After more than four years of research, Cornell’s Warden Lab published their results on Feb. 1. When the lab was established in 2014, the project’s goal was to understand serotonin’s functions.
“Serotonin is involved in many psychiatric disorders including depression. Many antidepressants target [the] serotonin system but they are not effective in many cases,” said Akash Guru grad in an email to The Sun. “We wanted to understand what the serotonin neurons do during normal behavior.”
According to Guru, experiments were conducted to explore behaviors in a stressful environment because the lab was interested in serotonin and depression. As the serotonin began to respond in a different way, the project took a different direction.
Researchers found that serotonin had impact on the fight-or-flight response in the mice being tested. When the mice were placed in stressful situations, serotonin would be released and inclined the mouse to flee. However, when in a less averse situation, the serotonin causes the mouse to remain still.
“Some of undergraduate students at the time first found that activity of serotonin showed opposite effect when animals run on running wheels and when animals struggle,” said Yi-Yun Ho grad in an email to The Sun. “This surprising effect led us to further study the environmental impact on serotonin.”
They discovered that serotonin’s effect on the mice differed by the situation, which causes what is called a context-oriented response. This is a new-found ability for the chemical and its context-based changing was unexpected for the researchers.
“This switch really surprised us,” said senior author Prof. Melissa Warden, neurobiology and behavior, in an interview with Science Daily. “It was our first clue that something really strange might be going on in the brain in emergency situations.”
According to Seo, understanding the basic function of serotonin will lead to better targeted medical treatment for many psychiatric diseases. Researchers speculated that the result could also explain why antidepressants targeting serotonin systems are sometimes ineffective.