Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Emotion-regulating protein lacking in panic disorder

22.01.2004


Three brain areas of panic disorder patients are lacking in a key component of a chemical messenger system that regulates emotion, researchers at the NIH’s National Institute of Mental Health (NIMH) have discovered. Brain scans revealed that a type of serotonin receptor is reduced by nearly a third in three structures straddling the center of the brain. The finding is the first in living humans to show that the receptor, which is pivotal to the action of widely prescribed anti-anxiety medications, may be abnormal in the disorder, and may help to explain how genes might influence vulnerability. Drs. Alexander Neumeister and Wayne Drevets, NIMH Mood and Anxiety Disorders Program, and colleagues, report on their findings in the January 21, 2004 Journal of Neuroscience.



Each year, panic attacks strike about 2.4 million American adults "out of the blue," with feelings of intense fear and physical symptoms sometimes confused with a heart attack. Unchecked, the disorder often sets in motion a debilitating psychological sequel syndrome of agoraphobia, avoiding public places. Panic disorder runs in families and researchers have long suspected that it has a genetic component. The new finding, combined with evidence from recent animal studies, suggests that genes might increase risk for the disorder by coding for decreased expression of the receptors, say the researchers.

NIMH grantee Dr. Rene Hen, Columbia University, and colleagues, reported in 2002 that a strain of gene "knockout" mice, engineered to lack the receptor during a critical period in early development, exhibit anxiety traits in adulthood, such as a reluctance to begin eating in an unfamiliar environment. More recent experiments with the knockout mice show that a popular SSRI (serotonin selective reuptake inhibitor) drug produces its anti-anxiety effects by stimulating the formation of new neurons in the hippocampus via the serotonin 5-HT1A receptor.


In the current study, Neumeister and Drevets used PET scans (positron emission tomography) to visualize 5-HT1A receptors in brain areas of interest in 16 panic disorder patients – seven of whom also suffered from major depression – and 15 matched healthy controls. A new radioactive tracer (FCWAY), developed by NIH Clinical Center PET scan scientists, binds to the receptors, revealing their locations and a numerical count by brain region. Subjects also underwent structural MRI (magnetic resonance imaging) scans, which were overlaid with their PET scan data to precisely match it with brain structures.

In the panic disorder patients, including those who also had depression, receptors were reduced by an average of nearly a third in the anterior cingulate in the front middle part of the brain, the posterior cingulate, in the rear middle part of the brain, and in the raphe, in the midbrain (See images below.). Previous functional brain imaging studies have implicated both the anterior and posterior cingulate in the regulation of anxiety. Stimulation of 5-HT1A receptors in the raphe regulates serotonin synthesis and release. In an earlier PET study of depressed patients, using a different tracer, Drevets and colleagues found less dramatic reductions of the receptor in the anterior and posterior cingulate, but a 41 percent reduction in the raphe. These findings add to evidence for overlap between depression and anxiety disorders.

Although animal experiments have shown that cortisol secretion triggered by repeated stress reduces expression of the gene that codes for the 5-HT1A receptor, such stress hormone elevations are usually not found in panic disorder. Noting the recent discovery of a variant of the 5-HT1A receptor gene linked to major depression and suicide, the researchers suggest that reduced expression of the receptor "may be a source of vulnerability in humans, and that abnormal function of these receptors appears to specifically impact the cortical circuitry involved in the regulation of anxiety."


Other researchers who participated in the study are Drs. Earle Bain, Allison Nugent, Omer Bonne, David Luckenbaugh, Dennis Charney, NIMH; Richard Carson, William Eckelman, Peter Herscovitch, Warren G. Magnuson Clinical Center.

The National Institute of Mental Health (NIMH) and the Warren G. Magnuson Clinical Center are parts of the National Institutes of Health (NIH), the Federal Government’s primary agency for biomedical and behavioral research. NIH is a component of the U.S. Department of Health and Human Services.

Jules Asher | EurekAlert!
Further information:
http://www.nimh.nih.gov/

More articles from Health and Medicine:

nachricht Nitric oxide-scavenging hydrogel developed for rheumatoid arthritis treatment
06.06.2019 | Pohang University of Science & Technology (POSTECH)

nachricht Infants later diagnosed with autism follow adults’ gaze, but seldom initiate joint attention
24.05.2019 | Schwedischer Forschungsrat - The Swedish Research Council

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

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

Im Focus: The hidden structure of the periodic system

The well-known representation of chemical elements is just one example of how objects can be arranged and classified

The periodic table of elements that most chemistry books depict is only one special case. This tabular overview of the chemical elements, which goes back to...

Im Focus: MPSD team discovers light-induced ferroelectricity in strontium titanate

Light can be used not only to measure materials’ properties, but also to change them. Especially interesting are those cases in which the function of a material can be modified, such as its ability to conduct electricity or to store information in its magnetic state. A team led by Andrea Cavalleri from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg used terahertz frequency light pulses to transform a non-ferroelectric material into a ferroelectric one.

Ferroelectricity is a state in which the constituent lattice “looks” in one specific direction, forming a macroscopic electrical polarisation. The ability to...

Im Focus: Determining the Earth’s gravity field more accurately than ever before

Researchers at TU Graz calculate the most accurate gravity field determination of the Earth using 1.16 billion satellite measurements. This yields valuable knowledge for climate research.

The Earth’s gravity fluctuates from place to place. Geodesists use this phenomenon to observe geodynamic and climatological processes. Using...

Im Focus: Tube anemone has the largest animal mitochondrial genome ever sequenced

Discovery by Brazilian and US researchers could change the classification of two species, which appear more akin to jellyfish than was thought.

The tube anemone Isarachnanthus nocturnus is only 15 cm long but has the largest mitochondrial genome of any animal sequenced to date, with 80,923 base pairs....

Im Focus: Tiny light box opens new doors into the nanoworld

Researchers at Chalmers University of Technology, Sweden, have discovered a completely new way of capturing, amplifying and linking light to matter at the nanolevel. Using a tiny box, built from stacked atomically thin material, they have succeeded in creating a type of feedback loop in which light and matter become one. The discovery, which was recently published in Nature Nanotechnology, opens up new possibilities in the world of nanophotonics.

Photonics is concerned with various means of using light. Fibre-optic communication is an example of photonics, as is the technology behind photodetectors and...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

SEMANTiCS 2019 brings together industry leaders and data scientists in Karlsruhe

29.04.2019 | Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

 
Latest News

Uncovering hidden protein structures

18.06.2019 | Life Sciences

Monitoring biodiversity with sound: how machines can enrich our knowledge

18.06.2019 | Life Sciences

Schizophrenia: Adolescence is the game-changer

18.06.2019 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>