Arthritis pain is a hot topic

[Guest guest]

September 26, 2002

Arthritis pain is a hot topic

Research on the way in which chilli peppers cause their burning

sensation has revealed a link with the pain experienced by patients with

arthritis, giving hope of novel strategies to block the pain

hypersensitivity seen in such conditions.

" The receptor activated by chilli peppers in the mouth and other tissues

also increases in the terminals of sensory neurons in the skin after

inflammation, and this contributes to pain hypersensitivity, " said lead

researcher Dr Clifford Woolf, from Massachusetts General Hospital in

Boston, USA.

The researchers found that the TRPV1 receptor, which responds to

capsaicin, the chemical behind the " hot " sensation in chilli peppers,

also responds to actual heat and low pH, which occurs in inflammation.

Furthermore, they found that the increased production of TRPV1 seen with

inflammation is mediated by a single molecule known as p38, located

within sensory neurons.

p38, which is itself activated by a specific growth factor acting on a

subset of sensory neurons, increases TRPV1 levels in the skin by up to

20 times, though it does not affect the activity of the gene coding for

the receptor.

" This means that the chilli pepper receptor is not being regulated by

the gene being switched on but by more protein being produced, an

unexpected form of regulation, " said Dr Ru-Rong Ji, a member of the

team.

" We could use an inhibitor to p38 to block the increase in TRPV1,

therefore blocking pain in patients who suffer from many diseases and

condition that involve inflammation. "

Dr Woolf added: " With these findings, we're starting to understand why

patients with arthritis or other inflammatory conditions are likely to

have increased pain and sensitivity to heat. "

The research is published in the journal Neuron.

http://www.medwire.md/email_red.asp?story_id=10861 & news_type=1