Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Reductions in blood oxygen levels in newborns could contribute to ADHD development

25.10.2004


A repetitive drop in blood oxygen levels in newborn rats, similar to that caused by apnea (brief pauses in breathing) in some human infants, is followed by a long-lasting reduction in the release of the brain neurotransmitter dopamine, according to an Emory University research study. Because dopamine promotes attention, learning, memory and a variety of higher cognitive functions, the researchers believe repetitive apnea during neonatal development may be one factor leading to the development of attention deficit hyperactivity disorder (ADHD). This research will be reported at the Society for Neuroscience annual meeting in San Diego on October 24 by Glenda Keating, PhD, and Michael Decker, PhD, of the Department of Neurology at Emory University’s School of Medicine. The research was funded by the National Heart Lung and Blood Institute and conducted by the Program in Sleep Medicine and the Department of Neurology at Emory University.



Apnea of prematurity occurs in up to 85 percent of all prematurely born human infants, and obstructive sleep apnea occurs in 3 to 27 percent of all children. Data from previous studies suggests that diminished release of brain dopamine may be responsible for behaviors such as impulsiveness and distractibility, reduced self control, and impaired learning, which are hallmark traits associated with ADHD. Previous studies in Dr. Decker’s laboratory at Emory have shown that newborn rats who experience repetitive drops in blood oxygen levels go on to develop behavioral traits similar to those seen in humans with ADHD. This is the first time, however, that researchers have linked repetitive reductions in blood oxygen levels during a period of critical brain development to long-lasting deficiencies in release of dopamine specifically within the striatum, which is one of the brain regions important in modulating behavior, learning and memory.

The scientists exposed newborn rats from 7 to 11 days old to either 20-second bursts of a gas containing low oxygen content or to bursts of compressed air. Once the rats matured into juveniles, the scientists studied their locomotive activity and brain dopamine levels. They found that juvenile rats exposed to brief reductions in oxygen during their neonatal period had a 50 percent reduction in release of dopamine and were hyperactive.


Traditionally, ADHD has been attributed to genetic causes, environmental toxins or maternal use of nicotine, alcohol or drugs. Also, researchers generally have believed that the newborn brain is somewhat resistant to subtle disturbances in blood oxygenation. This study demonstrates in rats, however, that while long-term decreases in the release of dopamine can occur following as few as five days of subtle, repetitive reductions in blood oxygen levels during a critical window of brain development, the hyperactivity and impaired learning that also occur are not noticeable until later, when juvenile animals are old enough to display these behaviors.

The Emory scientists found that juvenile rats exposed to repetitive drops in blood oxygen levels as newborns also had a 50 percent increase in the level of dopamine stored in the brain tissue of the striatum compared to control rats and a reduction in the release of dopamine, showing that instead of releasing dopamine, they were abnormally storing it. "By linking reductions in blood oxygen during critical times of development to changes in dopamine function, we hope to shed light on the mechanisms of ADHD, which have been poorly understood to this point," said Dr. Keating. "Our results show that a relatively common occurrence in newborns could have long-lasting negative effects, and we believe our model has great potential for creating new insights and leading to new interventions and therapies."

"Our research also could help explain why amphetamines, such as Ritalin, and other non-amphetamines, such as Wellbutrin, that increase levels of brain dopamine are an effective treatment for children with ADHD," Dr. Decker said. "So far scientists haven’t sorted out which neurotransmitters are responsible for this effect, but if that could be narrowed down to just dopamine, as suggested by our data, it would provide a basis for developing drugs without the potential addictive properties of existing therapies."

The Emory investigators are exploring different ways to measure altered behavioral outcomes in rats to further confirm the similarity of these behaviors to those identified in ADHD. They also are planning studies aimed at preserving the brain dopamine system in individuals at risk for repetitive reductions in blood oxygenation. These studies could include non-invasive, subtle dietary changes in the mother and the newborn.

Holly Korschun | EurekAlert!
Further information:
http://www.emory.edu

More articles from Health and Medicine:

nachricht Laser activated gold pyramids could deliver drugs, DNA into cells without harm
24.03.2017 | Harvard John A. Paulson School of Engineering and Applied Sciences

nachricht What does congenital Zika syndrome look like?
24.03.2017 | University of California - San Diego

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: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>