Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers discover possible markers for mental illness

04.12.2007
Researchers have discovered natural genetic differences that might help predict the most effective antipsychotic drugs for particular patients with mental disorders such as schizophrenia, Parkinson’s and drug addiction.

They found the differences in the gene for a molecule called the dopamine D2 receptor (DRD2), a protein present on brain cells that are sensitive to the neurotransmitter dopamine.

The receptor is known to play a key role in memory and in a variety of mental illnesses. Most antipsychotic drugs work at least in part by blocking this protein, but scientists don’t yet understand how this helps patients. Nor can they explain why some people respond well to certain antipsychotic drugs and others respond poorly.

“Our study shows that these differences affect normal brain activity and memory processing, and therefore may also be important in mental illness,” says principal investigator Wolfgang Sadee, program director in pharmacogenomics at the Ohio State University Medical Center.

... more about:
»DRD2 »RNA »SNP »Sadee »activity »antipsychotic »differences »markers

The findings could lead to tests that will enable doctors to match patients with certain mental illnesses to the most effective therapy, something they cannot do now.

The study was done in collaboration with Professor Alessandro Bertolino, University of Bari, Italy, who performed the clinical research. It is published online in the Proceedings of the National Academy of Sciences.

“Identifying these predictive markers is important because antipsychotic drugs are effective in only a portion of patients upon first treatment, and it takes a month or more to establish their efficacy,” says Sadee, who is also a professor of psychiatry and chair of the department of pharmacology.

“During this time, irreparable damage can result if the wrong antipsychotic is given to a patient.”

Sadee notes that the D2 receptor gene has been implicated in mental illness for some time, but that a variety of clinical studies have failed to consistently link variations in the gene to disease.

These findings may change that.

For this study, Sadee and his colleagues analyzed 68 autopsy samples of normal human brain tissue. For each case, the researchers measured and compared the amount of messenger RNA made by each of the two copies of the DRD2 gene. Messenger RNA is a molecule made when a gene is involved in making its protein.

In 15 of the 68 cases, the relative amounts of messenger RNA made by one gene in the pair was strikingly different from the amount made by the other. The disparity was a clue that something was different between the genes.

Comparisons of these DRD2 genes to the rest revealed three small differences in the DNA called single-nucleotide polymorphisms, or SNPs (pronounced ‘snips’).

SNPs are tiny natural variations between individuals that occur at certain positions in genes, providing landmarks in the genome.

SNPs often have no effect on the function of the gene or its protein, but, in this case, laboratory experiments showed that particular changes in two of the SNPs alters how the messenger RNA for DRD2 is processed.

That, in turn, changed the relative amounts of two variants of the protein that are made by the gene.

“The two variants of DRD2 have distinct functions, facilitating or inhibiting dopaminergic transmission, so that a change in their ratios is potentially critical,” Sadee says. “We believed that this change would enhance dopamine activity in the brain.”

The researchers then tested this hypothesis in normal human volunteers who took simple memory performance tests. The participants’ brain activity was monitored during the testing by functional magnetic resonance imaging (fMRI).

The results showed that volunteers with the two variant SNPs had significantly more brain activity than the usual SNPs for the same memory task.

“Their brain needed to ‘work’ more to get the same result,” Sadee says. The two SNPs were also associated with reduced memory performance and attentional control.

Sadee and his colleagues are now testing the relevance of the SNP markers in patients with schizophrenia and in patients with cocaine addiction.

Darrell E. Ward | EurekAlert!
Further information:
http://www.osumc.edu

Further reports about: DRD2 RNA SNP Sadee activity antipsychotic differences markers

More articles from Life Sciences:

nachricht Scientists uncover the role of a protein in production & survival of myelin-forming cells
19.07.2018 | Advanced Science Research Center, GC/CUNY

nachricht NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Future electronic components to be printed like newspapers

A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.

The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

A smart safe rechargeable zinc ion battery based on sol-gel transition electrolytes

20.07.2018 | Power and Electrical Engineering

Reversing cause and effect is no trouble for quantum computers

20.07.2018 | Information Technology

Princeton-UPenn research team finds physics treasure hidden in a wallpaper pattern

20.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>