Chronic pain research

[Guest guest]

Dear all

This research has been done at the University of Bristol, where I work.

Might be interesting to some of us at

<http://www.bris.ac.uk/news/2006/895.html>

Nina

New research shows that it is undamaged nerve fibres that cause ongoing

spontaneous pain, not those that are injured.

These unexpected findings, by Dr Laiche Djouhri, Professor Sally Lawson and

colleagues from the University of Bristol, UK, are reported in the Journal

of Neuroscience today [25 January, 2006].

Previous research into ongoing chronic pain has tended to focus on the

damaged nerve fibres after injury or disease and overlooked the intact

fibres. This new understanding may help pharmaceutical companies formulate

novel pain killers.

Professor Lawson said: “The cause of this ongoing pain and why it arises

spontaneously was not understood before. Now that we know the type of nerve

fibres involved, and especially that it is the undamaged fibres that cause

this pain, we can examine them to find out what causes them to continually

send impulses to the brain. This should help in the search for new

analgesics that are effective for controlling ongoing pain.”

" Chronic pain is a devastating and widespread problem, affecting one in

five adults across Europe. "

Professor Sally LawsonOngoing pain is a burning or sharp stabbing/shooting

pain that can occur spontaneously after nerve injury. Unlike ‘evoked’ pain

caused, for example, by hitting your thumb with a hammer, ongoing pain is

particularly difficult to live with because it is often impossible to treat

with currently available pain killers.

Djouhri and Lawson show that the nerve cells responsible are ‘nociceptors’

or damage detectors. There are thousands of these nerves cells, each of

which has a very long, fine nerve fibre emerging from it. These fibres run

within nerves and connect the skin or other tissues to the spinal cord.

When activated through damage or disease, these nerve fibres fire

electrical impulses that travel along the fibre from the site of injury to

the spinal cord, from where information is sent to the brain. The faster

the undamaged fine fibres fire, the stronger the ongoing pain becomes.

Dr Djouhri added: “The cause of this firing appears to be inflammation

within the nerves or tissues, caused by dying or degeneration of the

injured nerve fibres within the same nerve.”

The mechanism described by Djouhri and Lawson occurs following nerve injury

and in nerve and tissue inflammation. Further research is now needed to

establish how generally this mechanism may contribute to ongoing pain

associated with a wide variety of diseases such as back pain or shingles.

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Ms Nina Bunton

Department of Electrical & Electronic Engineering

Merchant Venturers Building

Woodland Road

Bristol BS8 1UB