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Scientists uncover the key to itchiness
by Jamie Anderson - August 8, 2009 - comments
The finding of a new research suggests that itching is not merely a low-level variation of pain, but a distinct sensation.
Washington, August 8: In a ground-breaking research that could lead to better treatments for skin conditions, researchers have uncovered explicit nerve cells guilty of causing itchiness.
Dr Glenn Giesler, an expert in itch at the University of Minnesota, said of the findings, “It could pinpoint targets for future treatments for itch, a common and sometimes debilitating condition produced by more than 50 diseases."
Pain and itch are different
The research, conducted by the Washington University School of Medicine in St. Louis and Peking University Third Hospital in Beijing, opposes popular myth that itch and pain are closely related.
Experiments by the researchers on mice established that some nerve cells transmit an itch sensation only.
After getting rid of mice itch cells, researchers found that the animals still responded to pain.
"This is a very striking and unexpected result because it suggests there is an itch-specific neuronal pathway in the spinal cord, Chen observed.
"We've shown that particular neurons are critical for the itching sensation but not for pain, which means those cells may contain several itch-specific receptors or signaling molecules that can be explored or identified as targets for future treatment or management of chronic itching," Washington University's Zhou-Feng Chen, lead author of the study said.
Mice are "one of the best models for itching, because so far we have found that all substances which can cause itching sensations in humans can also cause scratching behaviors in mice," Chen said.
First gene, GRPR
Back in 2007, researchers had recognized the first itch gene called gastrin-releasing peptide receptor (GRPR) which was active in the spinal cord.
However, the presence of GRPR in the spinal-cord did not clearly establish that the neurons were itch-specific. There was a likelihood that these were pain-related genes.
The present findings have important therapeutic implications. Highlighting the need for further research on the subject, Chen said, "We've shown that these GRPR neurons are important for itching sensation and not for pain, but we really don't know much more about them. We still have a lot of questions, and we are very interested to find more answers."
The findings of the present researchers have been published in the Aug. 6 issue of Science Express, the advance online publication of the journal Science.