The sensory receptor also underlies the response to a variety of environmental irritants, such as acrolein, the researchers report. Acrolein accounts for the toxic and inflammatory actions of tear gas, vehicle exhaust, tobacco smoke, and the byproducts of some chemotherapy drugs widely used in the treatment of cancer, severe arthritis, multiple sclerosis, and lupus. The insights therefore suggest potential new avenues for the development of anti-inflammatory and pain medications, according to the researchers.
The research team, led by David Julius at the University of California San Francisco, report cellular and behavioral evidence in mice linking the sensory ion channel TRPA1 to the pain response evoked by mustard oil, garlic, and acrolein. Mice deficient for TRPA1 also show pronounced deficits in their reaction to a natural agent produced in response to injury, inflammation, or oxygen shortage, they found.
"By understanding what triggers TRP channel receptors, we can learn something new about how pain is sensed," Julius said. The TRP family of channels includes receptors for a variety of natural plant products that elicit pain and inflammation by stimulating a subset of neurons, collectively known as nociceptors.
Earlier studies identified a heat-activated TRP channel as the receptor for capsaicin, the pungent ingredient in chili peppers. Similarly, a cold-activated channel underlies the response to menthol and other cooling agents, previous research showed.
While earlier evidence had shown mustard oil and garlic extract to stimulate TRPA1, it had not been determined whether the channel was their exclusive target, Julius said.
In the current study, the researchers examined wh
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Contact: Heidi Hardman
hhardman@cell.com
617-397-2879
Cell Press
23-Mar-2006