Neuron memory key to taming chronic pain

February 13, 2012

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 ...

Recommended for you

Chatter in the deep brain spurs empathy in rats

June 23, 2017

It's a classic conundrum: while rushing to get to an important meeting or appointment on time, you spot a stranger in distress. How do you decide whether to stop and help, or continue on your way?

How brains surrender to sleep

June 23, 2017

Scientists at the Research Institute of Molecular Pathology (IMP) in Vienna study fundamental aspects of sleep in roundworms. Using advanced technologies, they monitor the activity of all nerve cells in the brain while they ...

The neural relationship between light and sleep

June 23, 2017

Humans are diurnal animals, meaning that we usually sleep at night and are awake during the day, due at least in part to light or the lack thereof. Light is known to affect sleep indirectly by entraining—modifying the length ...

How pheromones trigger female sexual behavior

June 22, 2017

A study by a group of Japanese scientists showed how a male pheromone in mice enhances sexual behaviors in females—and how it may enhance a different behavior, aggression, in males—by identifying distinct neural circuits ...

Coupling of movement and vision

June 22, 2017

In a study published in Cell, Georg Keller and his group shed light on neural circuits in the cortex that underlie the integration of movement and visual feedback. They identified a mechanism in the visual cortex responsible ...

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.