Navigation Links
Penn researchers identify the roots of memory impairment resulting from sleep deprivation
Date:5/17/2011

PHILADELPHIA From high-school students to surgeons, anyone who has pulled an all-nighter knows there is a price to be paid the next day: trouble focusing, a fuzzy memory and other cognitive impairments. Now, researchers at Penn have found the part of the brain and the neurochemical basis for sleep deprivation's effects on memory.

Ted Abel, a professor of biology in Penn's School of Arts and Sciences and director of the University's interdisciplinary Biological Basis of Behavior program, led the research team. His partners included Cdrick Florian, a postdoctoral fellow in biology, and Christopher Vecsey, a neuroscience graduate student, as well as researchers from the Massachusetts Institute of Technology and Tufts University.

Their research was published in The Journal of Neuroscience.

Abel's group aimed to better understand the role of the nucleoside adenosine in the hippocampus, the part of the brain associated with memory function.

"For a long time, researchers have known that sleep deprivation results in increased levels of adenosine in the brain, and has this effect from fruit flies to mice to humans." Abel said. "There is accumulating evidence that this adenosine is really the source of a number of the deficits and impact of sleep deprivation, including memory loss and attention deficits. One thing that underscores that evidence is that caffeine is a drug that blocks the effects of adenosine, so we sometimes refer to this as 'the Starbucks experiment.'"

Abel's research actually involved two parallel experiments on sleep-deprived mice, designed to test adenosine's involvement in memory impairment in different ways.

One experiment involved genetically engineered mice. These mice were missing a gene involved in the production of glial transmitters, chemicals signals that originate from glia, the brain cells that support the function of neurons. Without these gliatransmitters, the engineered mice could not produce the adenosine the researchers believed might cause the cognitive effects associated sleep deprivation.

The other experiment involved a pharmacological approach. The researchers grafted a pump into the brains of mice that hadn't been genetically engineered; the pump delivered a drug that blocked a particular adenosine receptor in the hippocampus. If the receptor was indeed involved in memory impairment, sleep-deprived mice would behave as if the additional adenosine in their brains was not there.

To see whether these mice showed the effects of sleep deprivation, the researchers used an object recognition test. On the first day, mice were placed in a box with two objects and were allowed to explore them while being videotaped. That night, the researchers woke some of the mice halfway through their normal 12-hour sleep schedule.

On the second day, the mice were placed back in the box, where one of the two objects had been moved, and were once again videotaped as they explored to see how they reacted to the change.

"Mice would normally explore that moved object more than other objects, but, with sleep deprivation, they don't," Abel said. "They literally don't know where things are around them."

Both sets of treated mice explored the moved object as if they had received a full night's sleep.

"These mice don't realize they're sleep-deprived," Abel said.

Abel and his colleagues also examined the hippocampi of the mice, using electrical current to measure their synaptic plasticity, or how strong and resilient their memory-forming synapses were. The pharmacologically and genetically protected mice showed greater synaptic plasticity after being sleep deprived than the untreated group.

Combined, the two experiments cover both halves of the chemical pathway involved in sleep deprivation. The genetic engineering experiment shows where the adenosine comes from: glia's release of adenosine triphosphate, or ATP, the chemical by which cells transfer energy to one another. And the pharmacological experiment shows where the adenosine goes: the A1 receptor in the hippocampus.

The knowledge that interrupting the pathway at either end results in mice that show no memory impairments is a major step forward in understanding how to manage those impairments in humans.

"To be able to reverse a particular aspect of sleep-deprivation, such as its effect on memory storage, we really want to understand the molecular pathways and targets," Abel said. "Here, we've identified the molecule, the cellular circuit and the brain region by which sleep deprivation affects memory storage."

Such treatments would be especially enticing, given how sensitive the brain is to sleep deprivation's effects.

"Our sleep deprivation experiments are the equivalent of losing half of a night sleep for a single night," Abel said. "Most of us would think that's pretty minor, but it shows just how critical the need for sleep is for things like cognition."


'/>"/>

Contact: Evan Lerner
elerner@upenn.edu
215-573-6604
University of Pennsylvania
Source:Eurekalert

Related medicine news :

1. Researchers map all the fragile sites of the yeast Saccharomyces cerevisiaes genome
2. UH Case Medical Center researchers publish promising findings for advanced cervical cancer
3. Researchers discover new way to kill pediatric brain tumors
4. Researchers Who Discovered First Genes for Stuttering will Present Findings to the National Stuttering Association
5. Researchers create drug to keep tumor growth switched off
6. Urine protein test might help diagnose kidney damage from lupus, UT Southwestern researchers find
7. GUMC researchers say flower power may reduce resistance to breast cancer drug tamoxifen
8. Clemson researchers develop hands-free texting application
9. Researchers find biomarkers in saliva for detection of early-stage pancreatic cancer
10. Researchers chart genomic map spanning over 2 dozen cancers
11. Researchers discover second protective role for tumor-suppressor
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:4/30/2016)... ... April 30, 2016 , ... Orlando-based Maximized Living has ... go for gold in Rio. Under the care of Maximized Living doctors at ... In an unprecedented showing, Maximized Living is sending the largest contingent of elite chiropractors ...
(Date:4/29/2016)... ... April 29, 2016 , ... Memorial ... for Graduate Medical Education (ACGME) that it has received accreditation for its residency ... of three residency programs that Memorial is currently pursuing, including Pediatrics and Internal ...
(Date:4/29/2016)... ... April 29, 2016 , ... Dr. Bernie Siegel, ... "LOVE, MEDICINE and MIRACLES") addresses touchy topics related to Death live on ... Dr. Bernie Siegel, author of a plethora of essential books-to-read for physicians ...
(Date:4/29/2016)... ... ... Spine Team Texas, a comprehensive spine physician group specializing in the treatment of ... invited to be a featured speaker at the Texas Society of the American College ... , Dr. R. Scott McPherson, a physical medicine and rehabilitation specialist, will speak ...
(Date:4/29/2016)... ... ... the deadliest type of skin cancer. Although only about 1 percent of skin cancer cases ... 10,000 people are expected to die of melanoma this year. The risk increases with age, ... most commonly diagnosed cancers in young women. A recent breakthrough in genetic studies may give ...
Breaking Medicine News(10 mins):
(Date:4/29/2016)... April 29, 2016 Glycotope GmbH, ... today announces the appointment of Dr. Alfredo Zurlo ... is an oncologist with many years clinical experience and ... industries. His last role was at Mologen AG where ... Executive Board. Previously Dr. Zurlo held various positions at ...
(Date:4/28/2016)...  While Abbott,s announced purchase of St. Jude ... and stent business, healthcare research firm Kalorama Information ... into patient monitoring.  Kalorama said that patient monitoring ... with double-digit growth expected the next 5 years, ... Patient Monitoring . Abbott Laboratories agreed to ...
(Date:4/28/2016)... 2016 Dr. ... und Stephen Schmidt werden ... ArisGlobal®, ein führender Anbieter cloudbasierter Softwarelösungen für ... dass neue Führungskräfte zum Team Sicherheit und ... vielfältige Erfahrungen mitbringen.  Dies wird die Geschäftseinheit ...
Breaking Medicine Technology: