Key Neurotransmitter for Pain Discovered

March 22, 2005

Contact: Luke Frank, Senior Public Affairs Representative, 505/272-3679


ALBUQUERQUE, NM - Researchers at the University of New Mexico's MIND Imaging Center have developed a new technique for probing the brain's response to pain by studying neural activity in specific brain regions.

Glutamate, a major neurotransmitter that can be toxic a high levels, now has been implicated as one of the primary neurotransmitters in communicating pain in the brain. This breakthrough could lead to new treatments and medications for the sufferer of acute and/or chronic pain.

For the study, described in detail in a paper recently accepted by the prestigious NeuroImage Magazine, pain was produced by placing ice on a subject's foot for 10-minute increments.

This "painful" stimulus consistently provoked a dynamic increase in glutamate concentrations (nearly 10 percent from baseline) in the anterior cingulate cortex, detectable using proton Magnetic Resonance Spectroscopy (1H-MRS). Consistent increases in glutamine levels (another part of the glutamate neurotransmitter system) also were seen, which correlate strongly with the intensity of pain expressed by participants.

These new findings represent the first time a dynamic change in glutamate and glutamine levels (from baseline in response to an external stimulus) have been measured in a single proton MRS scanning session.

"Our study reveals that glutamate is clearly a major player in how the brain processes acute pain, so we will continue our research to determine its role in chronic pain," Principle Investigator Dr. Paul Mullins offers. "Pain is considered the fifth vital sign by many medical professionals, and we know that chronic pain negatively affects brain tissue, effectively shrinking regions of the brain."

Mullins further asserts that these preliminary findings lend support to the development of new analgesics that aggressively work on the "glutamate system" without debilitating the subject.

In cases of fibromyalgia, where pain is not associated with a distinctive bodily injury, there could be excess glutamate released in the brain unprovoked, which ultimately can break down the nerves and damage brain tissue. Physicians may be able to measure that reaction real-time with MRS, and treat accordingly.

According to Mullins, this is the first time researchers have been able to "view" in detail the chemical response in the brain of a subject suffering pain, providing a new opportunity to measure brain response to pain.

New understandings of how pain manifests itself in the brain could prompt new treatment protocols for painful acute injuries and chronic conditions that will improve recovery and prevent brain tissue damage associated with the pain.

Currently, UNM's MIND Imaging Center houses two MRI scanners from which structural (sMRI), functional (fMRI), and chemical (MRS) research of brain structure and activity can be undertaken. Recently, the MIND Imaging Center added a magnetoencephalography (MEG) machine, making it one of the most sophisticated neuroimaging centers in the world.

The MIND Institute (Mental Illness and Neuroscience Discovery), of which UNM's MIND Imaging Center is an integral component, is a group of internationally-recognized neuroimaging scientists and medical research institutions headquartered in Albuquerque, NM. The Institute is a partnership of universities, schools of medicine, national laboratories, and other scientific organizations in New Mexico, Massachusetts and Minnesota.

The University of New Mexico Health Sciences Center provides added value to health care through leadership in providing innovative, collaborative education; advancing frontiers of science through research critical to the future of health care; delivering health care services that are at the forefront of science; and facilitating partnerships with public and private biomedical and health enterprises. For more information on the UNM Health Sciences Center, visit .

Contact: Luke Frank, 272-3322

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