Newsroom | News Archive | Publications | Contact Us for Experts  
 
Karen Kreeger
(215) 349-5658
Related Links
Perelman School of Medicine
University of Pennsylvania Health System
 
 
> Epigenetics Shapes Fate of Brain vs. Brawn Castes in Carpenter Ants
> Molecular Master Switch for Pancreatic Cancer Identified, Potential Predictor of Treatment Outcome
> Eat to Dream: Penn Study Shows Dietary Nutrients Associated with Certain Sleep Patterns
  All News Releases
 
    Media Resources
 
spacerNEWS RELEASE spacer Print Version
OCTOBER 11, 2005
  Penn Study Finds Direct Role for Glial Cells in Brain Cross-talk
  Findings may help elucidate mechanisms of wake-sleep transitions and epileptic seizures
   

(Philadelphia, PA) - Researchers at the University of Pennsylvania School of Medicine have demonstrated that star-shaped glial cells in the brain called astrocytes are directly involved in regulating communication between neurons. A central finding of the study is that astrocytes modulate the level of a signaling molecule called adenosine, which is thought to be important in controlling wake-to-sleep transitions and epileptic seizures.

“This finding may cause neuroscientists to radically alter their view of the role of astrocytes as merely supportive to one of actively communicating with and instructing neurons,” states senior author Philip G. Haydon, PhD, Professor of Neuroscience. “Astrocytes are not just the ‘kitchen cells’ of the brain, providing nutritional support, but instead also help the neurons talk to each other.” Haydon and colleagues published their results in last week’s issue of Science.

The central nervous system, which includes the brain and spinal cord, is composed of specialized cells called neurons that send out and receive chemical signals called neurotransmitters across a space called the synapse. This process results in transmission of a nerve impulse. Historically, the glial cell or astrocyte was considered to be a support cell and to play no active role in regulating nerve impulse transmission. However, recent research by Haydon and other investigators has indicated that glial cells do produce chemical transmitters called gliotransmitters and that these chemical signals are recognized by the neurons. The studies that have shown capability were conducted on isolated nerve cells or on slices of brain tissue.

In this most recent study, the researchers made genetic manipulations to glial cells in live mice, thus directly demonstrating how astrocytes function in the brain. The mice were engineered to produce a protein called SNARE in their astrocytes. When the SNARE protein was produced, the amount of adenosine decreased.

When adenosine accumulated, nerve impulses were suppressed and could not be transmitted across the synapse. This helps explain why high adenosine levels can suppress epileptic seizures.

In contrast, low levels of adenosine increased the transmission of nerve impulses. The modulation of neuronal activity through the regulation of the level of adenosine in the synapse may explain the nature of wake-to-sleep transitions during periods of drowsiness.

“The next step is to study the behavior of these mice during manipulation of adenosine levels in the brain,” says Haydon.

The study was a collaboration between Haydon and Stephen Moss at Penn and Ken McCarthy, University of North Carolina, Chapel Hill. The lead author was Olivier Pascual, a post-doctoral fellow in Penn’s Department of Neuroscience. Co-authors are Kristi Casper, Cathryn Kubera, Jing Zhang, Raquel Revilla-Sanchez, Jai-Yoon Sul and HajimeTakano.

This study was funded by the National Institute of Neurological Disorders and Stroke and the National Institute of Mental Health.

###

PENN Medicine is a $2.7 billion enterprise dedicated to the related missions of medical education, biomedical research, and high-quality patient care. PENN Medicine consists of the University of Pennsylvania School of Medicine (founded in 1765 as the nation's first medical school) and the University of Pennsylvania Health System.

Penn’s School of Medicine is ranked #2 in the nation for receipt of NIH research funds; and ranked #4 in the nation in U.S. News & World Report’s most recent ranking of top research-oriented medical schools. Supporting 1,400 fulltime faculty and 700 students, the School of Medicine is recognized worldwide for its superior education and training of the next generation of physician-scientists and leaders of academic medicine.

The University of Pennsylvania Health System comprises: its flagship hospital, the Hospital of the University of Pennsylvania, consistently rated one of the nation’s “Honor Roll” hospitals by U.S. News & World Report; Pennsylvania Hospital, the nation's first hospital; Penn Presbyterian Medical Center; a faculty practice plan; a primary-care provider network; two multispecialty satellite facilities; and home health care and hospice.


 

 



About Penn Medicine   Contact Us   Site Map   Privacy Statement   Legal Disclaimer   Terms of Use

Penn Medicine, Philadelphia, PA 800-789-PENN © 2013, The Trustees of the University of Pennsylvania