Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Antidepressants Need New Nerve Cells to be Effective

29.08.2008
Researchers at UT Southwestern Medical Center have discovered in mice that the brain must create new nerve cells for either exercise or antidepressants to reduce depression-like behavior.

In addition, the researchers found that antidepressants and exercise use the same biochemical pathway to exert their effects.

These results might help explain some unknown mechanisms of antidepressants and provide a new direction for developing drugs to treat depression, said Dr. Luis Parada, chairman of developmental biology and senior author of a study in the Aug. 14 issue of the journal Neuron.

In animals, it was already known that long-term treatment with antidepressants causes new nerve cells to be generated in a part of the brain called the dentate gyrus. Exercise, which can also relieve the symptoms of depression, stimulates the generation of new nerve cells in the same area.

“We would never claim that what we study in mice directly relates to how antidepressants work in humans, but there are interesting features in parallel,” Dr. Parada said. “The study unifies different observations that point to the brain’s dentate gyrus region and to creation of nerve cells as being important in depression.”

Antidepressants act very quickly to increase levels of natural compounds, called neurotransmitters, which nerve cells use to communicate. It takes several weeks to several months, however, for the patients who respond to such treatments to feel less depressed. Dr. Parada said this implies that some other long-term mechanism is also at work.

The current study was designed to test several phenomena that have long been observed in animal studies but have not been studied together to see if they are linked, Dr. Parada said.

The researchers focused on a molecule called TrkB, or Track-B, which is found on the surface of nerve cells and responds to several growth factors to cause new nerves to grow in the dentate gyrus.

They genetically engineered mice to lack TrkB specifically in the stem cells that give rise to new neurons, then gave them antidepressants for several weeks or allowed them to run on wheels. When the mice were tested for depressive behavior, the tests revealed that neither the antidepressants nor the exercise had helped them, and the animals also had not grown new nerve cells in the dentate gyrus.

“At least in mice, this result directly links antidepressants and voluntary exercise with TrkB-mediated creation of nerve cells,” Dr. Parada said.

The results also showed that antidepressants required TrkB to stimulate the growth of new nerve cells.

Matching the timeframe for medicated patients to feel less depressed, it takes several weeks for new nerve cells to grow, Dr. Parada said. This parallel effect, he said, may mean that antidepressants need to stimulate growth of new cells in the dentate gyrus in order to achieve their full effect.

“We can get biochemical, physiological, behavioral and anatomical results in animal models,” Dr. Parada said. “These all resonate with the human condition, so perhaps you have a physiological relevancy.

“There could be a way to stimulate growth of nerve cells to fight depression, for example.”

Other UT Southwestern researchers involved in the study were lead author Yun Li, graduate student in developmental biology; Bryan Luikart, former graduate student in developmental biology; Dr. Shari Birnbaum, assistant professor of psychiatry; Jian Chen, student research assistant in developmental biology; Dr. Chang-Hyuk Kwon, instructor of developmental biology; Dr. Steven Kernie, associate professor of pediatrics; and Dr. Rhonda Bassel-Duby, associate professor of molecular biology.

The work was supported by the National Institute of Neurological Disorders and Stroke.

Visit http://www.utsouthwestern.org/neurosciences to learn more about UT Southwestern’s clinical services in neurosciences.

Dr. Luis Parada -- http://www.utsouthwestern.edu/findfac/professional/0,2356,15510,00.html

Aline McKenzie | Newswise Science News
Further information:
http://www.utsouthwestern.edu

More articles from Life Sciences:

nachricht Are there sustainable solutions in dealing with dwindling phosphorus resources?
16.10.2017 | Leibniz-Institut für Nutzierbiologie (FBN)

nachricht Strange undertakings: ant queens bury dead to prevent disease
13.10.2017 | Institute of Science and Technology Austria

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

Im Focus: New nanomaterial can extract hydrogen fuel from seawater

Hybrid material converts more sunlight and can weather seawater's harsh conditions

It's possible to produce hydrogen to power fuel cells by extracting the gas from seawater, but the electricity required to do it makes the process costly. UCF...

Im Focus: Small collisions make big impact on Mercury's thin atmosphere

Mercury, our smallest planetary neighbor, has very little to call an atmosphere, but it does have a strange weather pattern: morning micro-meteor showers.

Recent modeling along with previously published results from NASA's MESSENGER spacecraft -- short for Mercury Surface, Space Environment, Geochemistry and...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

Conference Week RRR2017 on Renewable Resources from Wet and Rewetted Peatlands

28.09.2017 | Event News

 
Latest News

A single photon reveals quantum entanglement of 16 million atoms

16.10.2017 | Physics and Astronomy

The melting ice makes the sea around Greenland less saline

16.10.2017 | Earth Sciences

On the generation of solar spicules and Alfvenic waves

16.10.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>