Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Specific regions of brain implicated in anorexia nervosa

07.07.2005


Overactive dopamine receptors may help explain eating disorder’s symptoms



Just why those with anorexia nervosa are driven to be excessively thin and seem unaware of the seriousness of their condition could be due to over-activity of a chemical system found in a region deep inside the brain, a University of Pittsburgh study suggests. Reporting in the journal Biological Psychiatry, researchers found an over-activity of dopamine receptors in the brain’s basal ganglia, an area known to play a role in how people learn from experience and make choices.

Results of the study, led by Walter Kaye, M.D., of the University of Pittsburgh School of Medicine, and Guido Frank, M.D., now of the University of California at San Diego, contribute to the understanding of what may cause anorexia. The disorder affects about 1 percent of American women, some of whom die from complications of the disease. The research may point to a molecular target for development of more effective treatments than those currently available.


The study is the first to use positron emission tomography (PET) imaging to assess the activity of brain dopamine receptors, a neurotransmitter system that is best known for its role in controlling movement. These receptors also are associated with weight and feeding behaviors and responses to reinforcement and reward. Researchers used a harmless molecule designed to bind to the dopamine D2 and D3 receptors that lie on the membrane surface of neurons. Ten women who had recovered from anorexia nervosa for more than a year were studied, as were 12 normal female subjects. Because malnourishment affects brain chemistry, the researchers did not include acutely ill women in their study.

Since other studies have found reduced binding of these dopamine receptors in both people who are obese and those who have substance use problems, Drs. Kaye and Frank hypothesized that they would find just the opposite in women with anorexia.

Indeed, there was increased receptor binding in the basal ganglia’s antero-ventral striatum in the women with a history of anorexia nervosa irrespective of their age, body mass index or time since recovery, but not in any of the healthy women. The antero-ventral striatum is an area known to modulate reward and reinforcement and is therefore important in learning from experience.

The researchers also found increased dopamine D2/D3 receptor activity in another part of the basal ganglia called the dorsal caudate, which is related to responses to and avoidance of harm. Such activity may help explain why women with anorexia exhibit exaggerated worry and concern about what might happen in the future.

"When they are ill, people with anorexia nervosa don’t seek or respond to the kinds of comforts and pleasures most of us enjoy, including food. They also resist and ignore feedback that signifies their precarious state of health. They don’t see an emaciated figure in the mirror, they ignore the most obvious warning signs and dismiss comments from loved ones that suggest they are seriously and medically ill. People with anorexia nervosa have extreme self-denial, not only of food, but often of many comforts and pleasures in life. Yet people with anorexia nervosa can be very energetic and productive," said Dr. Kaye, professor of psychiatry.

"Taken together, the alterations in the dopamine system may help explain the tell-tale symptoms of anorexia," added Dr. Kaye.

Alteration in dopamine function may affect the value of perceived rewards, or perhaps make it difficult to associate good feelings with things most people find rewarding, Dr. Kaye explained. Consequently, people with anorexia nervosa may appear to be obsessive about certain stimuli that may be uniquely rewarding to them, but may not be able to respond well to stimuli related to food or pleasure.

"This finding may help us better understand brain dopamine function across a whole spectrum of disorders, with respect to its contribution to the avoidance of food and other stimuli in anorexia nervosa on one end, and the desire for stimuli, such as in food and drug use on the other," added Dr. Frank, a fellow in child psychiatry.

More research is needed to address the many questions that remain, including what causes the dopamine receptors to be overactive in the first place. Genetic studies could yield some answers. Indeed, a study supported by the Price Foundation, which was recently published in the online edition of Neuropsychopharmacology, found alterations in genes for the D2 receptor in some individuals with anorexia nervosa. Dr. Kaye is a co-author of that paper and principal investigator of the Price Foundation studies, including a new multi-center study that is now recruiting families with two or more members who have or had anorexia nervosa to help identify the genes that contribute to the eating disorder.

In addition to Drs. Kaye and Frank, other authors include Carolyn C. Meltzer, M.D., Julie C. Price, Ph.D., Chester A. Mathis, Ph.D., Jessica Hoge and Scott Ziolko, all of the University of Pittsburgh School of Medicine department of radiology; Ursula F. Bailer, M.D., Shannon E. Henry and Angela Wagner, M.D., from the University of Pittsburgh School of Medicine department of medicine; Lisa Weissfeld, Ph.D., from the University of Pittsburgh Graduate School of Public Health department of biostatistics; Wayne Drevits, M.D., from the National Institute of Mental Health; and Nicole Barbarich-Marsteller from the State University of New York at Stony Brook. The research was supported by the National Institute of Mental Health (NIMH) and the Price Foundation. More information about the multi-center study funded by the NIMH can be found at www.angenetics.org.

Lisa Rossi | EurekAlert!
Further information:
http://www.upmc.edu
http://www.angenetics.org

More articles from Studies and Analyses:

nachricht New study: How does Europe become a leading player for software and IT services?
03.04.2017 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)

nachricht Reusable carbon nanotubes could be the water filter of the future, says RIT study
30.03.2017 | Rochester Institute of Technology

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

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

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

Im Focus: Quantum-physical Model System

Computer-assisted methods aid Heidelberg physicists in reproducing experiment with ultracold atoms

Two researchers at Heidelberg University have developed a model system that enables a better understanding of the processes in a quantum-physical experiment...

Im Focus: Glacier bacteria’s contribution to carbon cycling

Glaciers might seem rather inhospitable environments. However, they are home to a diverse and vibrant microbial community. It’s becoming increasingly clear that they play a bigger role in the carbon cycle than previously thought.

A new study, now published in the journal Nature Geoscience, shows how microbial communities in melting glaciers contribute to the Earth’s carbon cycle, a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

New quantum liquid crystals may play role in future of computers

21.04.2017 | Physics and Astronomy

A promising target for kidney fibrosis

21.04.2017 | Health and Medicine

Light rays from a supernova bent by the curvature of space-time around a galaxy

21.04.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>