Neuron memory key to taming chronic pain

February 13, 2012, McGill University

For some, the pain is so great that they can't even bear to have clothes touch their skin. For others, it means that every step is a deliberate and agonizing choice. Whether the pain is caused by arthritic joints, an injury to a nerve or a disease like fibromyalgia, research now suggests there are new solutions for those who suffer from chronic pain.

A team of researchers led by McGill neuroscientist Terence Coderre, who is also affiliated with the Research Institute of the McGill University Health Centre, has found the key to understanding how memories of are stored in the brain. More importantly, the researchers are also able to suggest how these memories can be erased, making it possible to ease chronic pain.

It has long been known that the "remembers" painful experiences, that they leave a memory trace of pain. And when there is new , the pain memory trace in the brain magnifies the feeling so that even a gentle touch can be excruciating.

"Perhaps the best example of a pain memory trace is found with phantom limb pain," suggests Coderre. "Patients may have a limb amputated because of gangrene, and because the limb was painful before it was amputated, even though the limb is gone, the patients continue to feel they are suffering from pain in the absent limb. That's because the brain remembers the pain. In fact, there's evidence that any pain that lasts more than a few minutes will leave a trace in the ." It's this memory of pain, which exists at the neuronal level, that is critical to the development of chronic pain. But until now, it was not known how these pain memories were stored at the level of the neurons.

Recent work has shown that the PKMzeta plays a crucial role in building and maintaining memory by strengthening the connections between neurons. Now Coderre and his colleagues have discovered that PKMzeta is also the key to understanding how the memory of pain is stored in the neurons. They were able to show that after painful stimulation, the level of PKMzeta increases persistently in the central nervous system (CNS).

Even more importantly, the researchers found that by blocking the activity of PKMzeta at the neuronal level, they could reverse the hypersensitivity to pain that neurons developed after irritating the skin by applying capsaicin – the active ingredient in hot peppers. Moreover, erasing this pain memory trace was found to reduce both persistent pain and heightened sensitivity to touch.

Coderre and his colleagues believe that building on this study to devise ways to target PKMzeta in pain pathways could have a significant effect for patients with chronic pain. "Many pain medications target pain at the peripheral level, by reducing inflammation, or by activating analgesia systems in the brain to reduce the feeling of pain," says Coderre. "This is the first time that we can foresee medications that will target an established pain as a way of reducing pain hypersensitivity. We believe it's an avenue that may offer new hope to those suffering from ."

Explore further: The protein that makes us remember pain

More information: The full article can be found at: www.molecularpain.com/content/7/1/99

Related Stories

The protein that makes us remember pain

May 13, 2011
(PhysOrg.com) -- New research by scientists in Arizona in the US has demonstrated that an enzyme makes the body remember and remain sensitive to pain after an injury has healed.

Opioids erase memory traces of pain

January 16, 2012
A team of researchers at the MedUni Vienna's Department of Neurophysiology (Centre for Brain Research) has discovered a previously unknown effect of opioids: the study, which has now been published in Science and was led ...

Treatment of chronic low back pain can reverse abnormal brain activity and function

May 17, 2011
It likely comes as no surprise that low back pain is the most common form of chronic pain among adults. Lesser known is the fact that those withchronic pain also experience cognitive impairments and reduced gray matter in ...

Recommended for you

Epilepsy linked to brain volume and thickness differences

January 22, 2018
Epilepsy is associated with thickness and volume differences in the grey matter of several brain regions, according to new research led by UCL and the Keck School of Medicine of USC.

Research reveals atomic-level changes in ALS-linked protein

January 18, 2018
For the first time, researchers have described atom-by-atom changes in a family of proteins linked to amyotrophic lateral sclerosis (ALS), a group of brain disorders known as frontotemporal dementia and degenerative diseases ...

Fragile X finding shows normal neurons that interact poorly

January 18, 2018
Neurons in mice afflicted with the genetic defect that causes Fragile X syndrome (FXS) appear similar to those in healthy mice, but these neurons fail to interact normally, resulting in the long-known cognitive impairments, ...

How your brain remembers what you had for dinner last night

January 17, 2018
Confirming earlier computational models, researchers at University of California San Diego and UC San Diego School of Medicine, with colleagues in Arizona and Louisiana, report that episodic memories are encoded in the hippocampus ...

Recording a thought's fleeting trip through the brain

January 17, 2018
University of California, Berkeley neuroscientists have tracked the progress of a thought through the brain, showing clearly how the prefrontal cortex at the front of the brain coordinates activity to help us act in response ...

Midbrain 'start neurons' control whether we walk or run

January 17, 2018
Locomotion comprises the most fundamental movements we perform. It is a complex sequence from initiating the first step, to stopping when we reach our goal. At the same time, locomotion is executed at different speeds to ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.