Stress, whether chronic or acute, can lead to major depression in susceptible people. How?
However, the precise mechanism remains largely obscure, and scientists think it can be found in the metabolic processes of brain cells.
Recent examinations have demonstrated that stress exhausts the brain’s energy reserves – causes depression to grab hold. That suggests the disorder could be treated by reversing the procedure and stimulating the brain’s metabolism.
Neurobiologists at EPFL tested this hypothesis on lab mice and found that giving a supplement to mice that contains acetyl-L-carnitine – a compound known to invigorate cell metabolism– reduces the manifestations of depression.
Administrating Acetyl-L-carnitine to mice reduces the likelihood that mice will exhibit depressive behaviors. Scientists also used spectroscopy to observe whether the compound stimulates cellular metabolism. They found that acetyl-L-carnitine stimulates cellular metabolism in the nucleus accumbens, a specific area in the brain that plays a vital role in reward, effort, and motivation systems.
The experiment was performed on four mice ranging from high social rank to low social rank. During the study, the mice were exposed to stress conditions and found that only the high-rank mice showed depressive symptoms.
Carmen Sandi, the study’s lead author and head of EPFL’s Behavioral Genetics Laboratory, said, “High-rank mice are accustomed to being in control of a situation. But under our stress protocol – where they were physically constrained – they found themselves completely powerless.”
Then by using standard behavioral tests, depending on sociability and decision-making capabilities, scientists used the degree of depression in mice that had and had not been administered acetyl-L-carnitine.
Sandi said, “Our brain makes up just 2% of our body mass but accounts for 20% of the energy we burn, so it’s not surprising that stress affects our metabolism. Our brains’ plasticity is highly solicited when we’re in stressful situations, which means that giving a boost to brain-cell mitochondria could help them maintain energy levels and therefore stave off depression.”
The study suggests that acetyl-L-carnitine can affect both cellular functioning and behavior. She, along with her colleagues, further expect to conduct similar tests on humans.
The study is published in the journal eLife.