http://www.newscientist.com/article.ns?id=mg19626244.600&feedId=online-news_rss20
Chilli-based anaesthetic won't leave you drooling
* 04 October 2007
* NewScientist.com news service
Hate being left numb and drooling after visiting the dentist? A local
anaesthetic that targets just pain-sensing neurons could make these
trips less traumatic.
Local anaesthetics such as lignocaine work by diffusing into all
neurons and blocking channels that transport sodium ions across cell
membranes - leaving the person in the dentist's chair pain-free but numb.
Clifford Woolf and his colleagues at Harvard Medical School have now
discovered a way of blocking just the pain neurons using capsaicin -
the active ingredient in chilli peppers - along with a version of
lignocaine that can't diffuse through cell membranes unassisted.
Capsaicin activates the TRPV1 receptor on pain neurons. This in turn
opens up a channel on the neurons' membrane, allowing the lignocaine
to pass though. The drug then gets to work blocking the sodium
channels. In tests on rats the drug combination completely blocked
pain without affecting motor function or other senses (Nature, DOI:
10.1038/nature06191).
Woolf's team is testing other chemicals that can activate the TRPV1
receptor, since people may not like the initial pain of a dose of
chilli pepper. Tests on volunteers are expected within two years.
From issue 2624 of New Scientist magazine, 04 October 2007, page 22
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((Udhay Shankar N)) ((udhay @ pobox.com)) ((www.digeratus.com))
