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 How brains surrender to sleep
23.06.2017 | IMP - Forschungsinstitut für Molekulare Pathologie GmbH

nachricht A new technique isolates neuronal activity during memory consolidation
22.06.2017 | Spanish National Research Council (CSIC)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>