(Press-News.org) BOSTON (April 14, 2011, noon ET) — The circadian system that controls normal sleep patterns is regulated by a group of glial brain cells called astrocytes, according to a study published online on April 14th in Current Biology, a Cell Press publication. Neuroscientists from Tufts University School of Medicine found that disruption of astrocyte function in fruit flies (Drosophila) led to altered daily rhythms, an indication that these star-shaped glial cells contribute to the control of circadian behavior. These results provide, for the first time, a tractable genetic model to study the role of astrocytes in circadian rhythms and sleep disorders.
According to the National Institute of Neurological Disorders and Stroke, more than 40 million Americans suffer from sleep disorders. Some sleep disorders arise from changes to the internal clock that is modulated by environmental signals, including light. Biologically, the internal clock is known to be composed of a network of neurons that controls rhythmic behaviors. Rob Jackson and his team previously had found that normal circadian rhythms require a glial-specific protein. In the new study, the team demonstrates that glia, and particularly astrocytes, are active cellular elements of the neural circuit that controls circadian rhythms in the adult brain.
"This is significant because glia have been traditionally viewed as support cells rather than independent elements that can regulate neurons and behavior. Neurons have had center stage for some time but current research is establishing the role of glial cells in brain function," said Rob Jackson, PhD, professor of neuroscience at Tufts University School of Medicine (TUSM) and member of the genetics and neuroscience program faculties at the Sackler School of Graduate Biomedical Sciences at Tufts. Jackson is also the director of the Center for Neuroscience Research (CNR) at TUSM.
"We used cellular and molecular genetic techniques to manipulate glial cells in the adult brain of fruit flies and found that such cells regulate neurons of the circadian network and behavior" said first author Fanny Ng, PhD, a postdoctoral associate in the Jackson lab. Ng added, "this is the first study to show that glia can modulate the release of a neuronal factor that is essential for normal circadian behavior."
Jackson's team observed altered rhythms in locomotor activity with glial manipulations, an indication the circadian clock had been disrupted, which in humans can contribute to jet lag or serious sleep disorders.
"In order to develop treatments for these disorders, we need to understand their cellular and molecular bases. Our work suggests that Drosophila can serve as a model system for genetic and molecular approaches to understand astrocyte function and astrocyte-neuron interactions. This undoubtedly will contribute to a better understanding of sleep and other neurological disorders that result from circadian dysfunction," said Jackson.
###
An additional author on this paper is Michelle Tangredi, PhD, a graduate of the Sackler program in neuroscience and a postdoctoral associate in Jackson's lab.
This research was funded by grants from the National Heart, Lung and Blood Institute and the National Institute of Neurological Disorders and Stroke (NINDS) and a training grant from the National Institute of Child Health and Human Development, all of the National Institutes of Health, and an award from the Russo Family Charitable Foundation Trust through TUSM. The Center for Neuroscience Research is funded by NINDS and Tufts University.
Ng FS, Tangredi MM, and Jackson FR. Current Biology. "Glial cells physiologically modulate clock neurons and circadian behavior in a calcium-dependent manner." DOI 10.1016/j.cub.2011.03.027
About Tufts University School of Medicine and the Sackler School of Graduate Biomedical Sciences
Tufts University School of Medicine and the Sackler School of Graduate Biomedical Sciences at Tufts University are international leaders in innovative medical education and advanced research. The School of Medicine and the Sackler School are renowned for excellence in education in general medicine, biomedical sciences, special combined degree programs in business, health management, public health, bioengineering and international relations, as well as basic and clinical research at the cellular and molecular level. Ranked among the top in the nation, the School of Medicine is affiliated with six major teaching hospitals and more than 30 health care facilities. Tufts University School of Medicine and the Sackler School undertake research that is consistently rated among the highest in the nation for its effect on the advancement of medical science.
If you are a member of the media interested in learning more about this topic, or speaking with a faculty member at the Tufts University School of Medicine, the Sackler School of Graduate Biomedical Sciences, or another Tufts health sciences researcher, please contact Siobhan Gallagher at 617-636-6586.
Rising star of brain found to regulate circadian rhythms
2011-04-15
ELSE PRESS RELEASES FROM THIS DATE:
Carbon sequestration estimate in US increased -- barring a drought
2011-04-15
CORVALLIS, Ore. – A research group has concluded that forests and other terrestrial ecosystems in the lower 48 states can sequester up to 40 percent of the nation's fossil fuel carbon emissions, a larger amount than previously estimated – unless a drought or other major disturbance occurs.
Widespread droughts, such as those that occurred in 2002 and 2006, can cut the amount of carbon sequestered by about 20 percent, the scientists concluded in a recent study that was supported by the National Science Foundation and U.S. Department of Energy.
The research, published ...
Study: Compassion, not sanctions, is best response to workplace anger
2011-04-15
Challenging traditional views of workplace anger, a new article by a Temple University Fox School of Business professor suggests that even intense emotional outbursts can prove beneficial if responded to with compassion.
Dr. Deanna Geddes, chair of the Fox School's Human Resource Management Department, argues that more supportive responses by managers and co-workers after displays of deviant anger can promote positive change at work, while sanctioning or doing nothing does not.
"The trouble with sanctions: Organizational responses to deviant anger displays at work," ...
Toward a more efficient use of solar energy
2011-04-15
This release is available in German.
The exploitation and utilization of new energy sources are considered to be among today's major challenges. Solar energy plays a central role, and its direct conversion into chemical energy, for example hydrogen generation by water splitting, is one of its interesting variants. Titanium oxide-based photocatalysis is the presently most efficient, yet little understood conversion process. In cooperation with colleagues from Germany and abroad, scientists of the KIT Institute for Functional Interfaces (IFG) have studied the basic mechanisms ...
Wikipedia deemed a reliable source for political info by new study
2011-04-15
Not so long ago Wikipedia was considered a playground for Capitol Hill staffers to game the system and make "the boss look better and the opponent look ridiculous."
Now a peer-reviewed study by Brigham Young University political scientist Adam Brown validates Wikipedia as a reliable place to get a political education.
The research focused on past and present candidates for governor across the 50 states. Brown fact-checked biographical information and voting statistics and found very few inaccuracies.
"My finding is optimistic for the health of our country," said ...
A sleep strategy commonly used by night nurses throws off their circadian clocks
2011-04-15
As many as 25 percent of hospital nurses go without sleep for at least 24 hours in order to adjust to working on the night shift, which is the least effective strategy for adapting their internal, circadian clocks to a night-time schedule.
That is one of the results of the first study to examine the strategies that night nurses use to adjust between day and night sleep cycles. The study was based on questionnaires from 388 nurses who work at the Vanderbilt University Medical Center and the results are published in the April 13 issue of the scientific journal, Public ...
New ACE survey shows people with type 2 diabetes experience low blood sugar during typical daily activities
2011-04-15
SAN DIEGO, Calif., April 14, 2011 – New survey data released today at the American Association of Clinical Endocrinologists (AACE) 20th Annual Meeting and Clinical Congress reveal that more than half (55%) of people with type 2 diabetes across the country report they have experienced hypoglycemia, or low blood sugar. What's more, many experienced it during typical daily activities such as working (42%), exercising (26%) and driving (19%), according to the survey, designed by the American College of Endocrinology (ACE) and supported by Merck. Recognizing symptoms like nervousness, ...
Temporary memory loss strikes hospitalized seniors
2011-04-15
CHICAGO --- Battling an illness, lack of sleep and strange surroundings can make any hospital patient feel out of sorts.
For seniors, hospitalizations actually may cause temporary memory loss and difficulty in understanding discharge instructions, according to a new Northwestern Medicine study.
The seniors go back to normal one month after the hospital stay, the study found. But immediately following a hospitalization is a critical time in which seniors may need extra support from healthcare professionals and family, according to Lee Lindquist, the lead author of ...
Recent census in war-torn DR Congo finds gorillas have survived, even increased
2011-04-15
A census team led by the Wildlife Conservation Society and the Insitut Congolais pour la Conservation de la Nature (ICCN) in Kahuzi-Biega National Park in the Democratic Republic of Congo today announced some encouraging news from a region plagued by warfare and insecurity: a small population of Grauer's gorillas has not only survived, but also increased since the last census.
The census, conducted late 2010 in the highland sector of Kahuzi-Biega National Park, revealed the presence of 181 individual Grauer's gorillas, up from 168 individuals detected in the same sector ...
Study suggests enzyme crucial to DNA replication may provide potent anti-cancer drug target
2011-04-15
LA JOLLA, CA – April 14, 2011 – An enzyme essential for DNA replication and repair in humans works in a way that might be exploited as anti-cancer therapy, say researchers at The Scripps Research Institute and Lawrence Berkeley National Laboratory.
The research, published in the April 15, 2011 issue of the journal Cell, focused on a member of a group of enzymes called flap endonucleases, which are essential to the life of a cell. The findings show new, clearly defined crystal structures of the enzyme FEN1 in action—demonstrating it functions in a way opposite to accepted ...
Study finds diet plus exercise is more effective for weight loss than either method alone
2011-04-15
SEATTLE – Everyone knows that eating a low-fat, low-calorie diet and getting regular exercise helps shed pounds, but a new study led by researchers at Fred Hutchinson Cancer Research Center has found that when it comes to losing weight and body fat, diet and exercise are most effective when done together as compared to either strategy alone.
The results of this randomized trial, led by Anne McTiernan, M.D., Ph.D., director of the Prevention Center and a member of the Hutchinson Center's Public Health Sciences Division, were published online April 14 in Obesity.
The majority ...