CHARLOTTESVILLE, Va., Sept. 21, 2005 -- We all know that if you putyour hand over an open flame it's very painful. What you may not knowis that, for some people, just lying under a blanket is painful aswell. They have neuropathic pain--annoying, chronic pain that comesfrom a diseased nerve cell rather than a specific stimulus. Feelingphantom pain in a missing limb is another, more famous, example.
Experts say up to two percent of the U.S. population suffers fromneuropathic pain. But this pain generally responds poorly to analgesicsand other standard treatment and get worse over time, causing permanentdisability in some people. Now there may be new hope for these painsufferers.
Scientists at the University of Virginia Health System have identifieda new type of pain-sensing neuron in rats, which are unusually dense ina subtype of calcium channels called T-type channels. It is possiblethat these "T-rich cells" could be targets for future therapies totreat neuropathic pain as well as acute onset pain, which can happenafter invasive surgery or inflammation.
A UVa anesthesiologist, Dr. Slobodan Todorovic, and his colleaguesidentified these novel cells and believe that the T-type calciumchannels in them may serve as a volume control for pain impulses. "Wehope that this new type of neuron will be amenable to new therapies.The next step will be to find a drug to block the action of thesecalcium channels," Todorovic said.
It was once thought that calcium channels were only important for brainfunction. But, Todorovic and his team show that the T-type channels areimportant to the functioning of peripheral nerves, especially when thenerves are injured.
A PhD student in UVa's neuroscience graduate program, Mike Nelson,discovered these T-rich nerve cells in Todorovic' lab. "It's veryexciting to make an initial observation like this," Nelson said. "It'sone reason we go to grad school in the first place." There are no drugsnow that effectively treat neuropathic pain, Nelson added. "Hopefully,observations like this will lead to new and more efficacious drugs inthe future. Our findings are another piece of evidence that thesecalcium channels are excellent targets for new analgesic development."
Their findings are published in the Sept. 21st issue of The Journal of Neuroscience found online at http://www.jneurosci.org/.
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