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twilyth
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No one really understands why some people experience chronic pain even after the initial cause of the pain is resolved or why chronic pain can evolve to the point where even non-painful stimuli like touching can cause pain. The problem seems to be with the nervous system itself and specifically, a particular region of the brain.
Article
from page 2
Article
from page 2
Min Zhuo, a neuroscientist at the University of Toronto, has been testing out potential painkillers on mice. But first he had to give the animals chronic pain, by crimping a nerve in one of their legs. In a matter of days, the mice developed many of the symptoms—and even some of the brain alterations—seen in people with chronic pain.
Zhuo and his colleagues then sought out compounds that could interfere with the learning that goes on during chronic pain. They focused on the behavior of neurons in a region of the brain called the anterior cingulate cortex, which shows especially intense activity in scans of people with chronic pain. The cingulate cortex contains an abundant amount of an enzyme called AC1. Zhuo wondered if the neural learning that leads to chronic pain was accelerated when levels of the enzyme were high.
As a test, Zhuo’s team genetically engineered mice so that they could not make enzyme AC1. The animals turned out almost entirely normal. They could even sense regular types of pain. But when Zhuo tied off a leg nerve, the mice didn’t develop chronic pain.
Once Zhuo recognized that AC1 is essential for chronic pain, he started the hunt for a drug that could interfere with it. He grew cells that produced enzyme AC1 in culture and then added hundreds of different compounds, hoping that one would latch on to the enzyme and thus block its action. Eventually he and his team found one that did, naming it NB001. When scientists gave an oral dose of NB001 to rats suffering from chronic pain, the animals were rid of their symptoms in just 45 minutes. By latching onto AC1, it seems, the drug prevented the neuronal activity that makes chronic pain possible.
NB001 shows a lot of promise. With its focus on the pain engine in the cingulate cortex instead of the entire brain and nervous system, it is particularly targeted. And there are no obvious side effects in labora*tory animals; the rats suffered no harm to their memory or their ability to learn. Zhuo hopes to launch clinical trials in humans soon.