Research Summary: Scientists Identify New Pathway In The Brain That Can Be Targeted To Alleviate Depression

What is the topic?

This study looks at a new pathway in the brain that may be able to be targeted by medication to alleviate depression symptoms. This is important, because many patients with depression have found time and time again that many antidepressants have failed them. Examining a new brain pathway, affected by antidepressants, opens up a new door for medication and treatment for all patients with depressive disorders. This new pathway could allow for new drugs to be developed to target new areas of the brain, which could ease depression symptoms in many patients.

The researchers first and foremost linked that current antidepressant drugs on today’s market (typically tricyclic antidepressants) target a specific pathway on the hippocampus, called the BMP signaling pathway. This finding was linked before the study was carried out. This finding has shown that typical antidepressants inhibit this pathway. This leads to the pathway to enable brain cells to produce more neurons. The specific neurons in this pathway enable brain stem cells to produce neurons that have a large effect on mood regulation and the production of memories.

(Note: Pathways are groups of molecules inside of a specific cell. These molecules work together for the cell to function properly. After the first molecule in a cell is enabled, a chain reaction occurs. Each cell will be triggered, allowing specific functioning to occur for the cell as a whole).

What was the hypothesis?

The hypothesis for this study was that the BMP signaling pathway would have antidepressant effects when inhibited by a protein called Noggin.

What did the researchers hope to learn? 

The aim of the study was to gain more knowledge how all antidepressants work inside of, and affect, the brain. The researchers hoped to find new pathways that would open the door for new drugs. They presumed that, if they could stimulate specific areas of the BMP pathway with specific proteins, they may be able to alleviate depression symptoms. If they succeeded, this would be the first drug of its kind to work on this pathway. This would help thousands of depression patients who do not currently get relief from the current antidepressants on the market.

How was the study conducted?

After the researchers confirmed the importance of the BMP pathway, they testes a specific brain protein called Noggin on mice with induced depression. Noggin itself stimulates neurogenesis (the birth of new neurons) by inhibiting the BMP pathway and stimulating certain areas of the pathway.

The researchers injected Noggin into the mice and critically observed them. They tested Noggin’s effects on mood by running specific behavioral tests for anxiety and depression prevalence in the mice.

What did the researchers find?

The results were statistically significant, as they found that using Noggin to block the pathway (and therefore increasing neurogenesis) had a stronger antidepressant effect than Prozac and tricyclics. Not only were the results stronger, but they were also more precise, which is important when trying to avoid side effects of medications. The antidepressant effect Noggin had on mice was very large. The mice with the Noggin injection were significantly less anxious and more active than the mice who did not receive the Noggin injections.

What were the limitations of the study?

Although this is a huge breakthrough for treatments of depression, we are a far ways away from identifying a ‘cure’ for depression. This study does not offer understanding in the neural changes and biological factors leading to depression (few studies do), but the findings offer a new target in aid for developing new drugs.

What do the results mean for you?

If you or a loved one has depression, these new findings are very important to patients and scientists alike. Targeting a new area of the brain that could possibly lead to new medications is always a big deal. This is especially important if you are a patient with depression, and feel that medications in the past have never worked for you. This opens a whole new door for possible treatment, and hope for tomorrow!

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