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New Insights on Action of Antidepressants

New Insights on Action of AntidepressantAustralian researchers believe they have discovered new information on how antidepressants stimulate the brain to improve a person’s mood.

The University of Queensland scientists discovered the class of drugs that increase levels of a neurotransmitter known as ‘norepinephrine’ triggers neurogenesis — the growth of new neurons — in a brain region called the hippocampus.

“If you block hippocampus neurogenesis, antidepressants no longer work,” lead researcher Dr. Dhanisha Jhaveri said.

“That suggests antidepressants must up-regulate neurogenesis in order for them to actually have any effect on behavior.”

However, the neuroscientists also found not all antidepressants worked in the same way.

Dr. Jhaveri said surprisingly, the class of antidepressants that increase levels of the neurotransmitter called serotonin – Prozac is a common example – fails to stimulate neurogenesis.

“Norepinephrine is basically binding directly onto the precursors which then initiate a signal which leads to the production of more neurons,” she said.

“Serotonin just doesn’t do that. Prozac doesn’t work by regulating the precursor activity – it may work outside that region, but it isn’t regulating the hippocampus directly. More research is needed to find out what serotonin actually does.”

Using rodent models, the research, published in the Journal of Neuroscience , established that selectively blocking the reuptake of norepinephrine directly activated hippocampal stem cells thereby discovering a much larger pool of dormant precursors in the hippocampus than previously thought to exist.

The researchers also improved their understanding of the mechanisms by which norepinephrine activated the precursors in the hippocampus and found the expression of beta3 adrenergic receptors is critical in mediating the effect.

Fellow researcher and team leader Professor Perry Bartlett said armed with this information, the team would be able to explore improved treatments for depression as well as dementia.

“Since dementia, especially in the aging population, appears to be related to a decrease in neurogenesis this discovery opens up exciting new ways to stimulate the production of new neurons to alleviate the devastating effects of dementia in our society,” Professor Bartlett said.

Dr. Jhaveri said the findings would also allow researchers to develop specific and more effective antidepressants.

“Depression is such a complex disorder, so we are going to test different behavioral outcomes to see whether the compounds that increase norepinephrine levels or stimulate beta3 adrenergic receptors work only for certain aspects of depression. We just don’t know yet but it may, for example, improve learning and memory, or reduce anxiety,” Dr. Jhaveri said.

Source: University of Queensland

New Insights on Action of Antidepressants

Rick Nauert PhD

Rick Nauert, PhDDr. Rick Nauert has over 25 years experience in clinical, administrative and academic healthcare. He is currently an associate professor for Rocky Mountain University of Health Professionals doctoral program in health promotion and wellness. Dr. Nauert began his career as a clinical physical therapist and served as a regional manager for a publicly traded multidisciplinary rehabilitation agency for 12 years. He has masters degrees in health-fitness management and healthcare administration and a doctoral degree from The University of Texas at Austin focused on health care informatics, health administration, health education and health policy. His research efforts included the area of telehealth with a specialty in disease management.

APA Reference
Nauert PhD, R. (2018). New Insights on Action of Antidepressants. Psych Central. Retrieved on November 28, 2020, from
Scientifically Reviewed
Last updated: 8 Aug 2018 (Originally: 22 Feb 2010)
Last reviewed: By a member of our scientific advisory board on 8 Aug 2018
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