Scientists Find Gene That Controls Pain Response

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Thursday January 10 1:27 PM ET

Scientists Find Gene That Controls Pain Response

By Amy Norton

NEW YORK (Reuters Health) - Pointing to possible new ways to combat

chronic pain, research in mice shows that a gene called DREAM plays a

key role in pain perception.

Scientists found that mice engineered to lack the gene had significant

reductions in a range of pain responses. The findings on the DREAM gene

could lead to a ``completely new target'' for pain control, the study's

lead author told Reuters Health.

The results are published in the January 11th issue of the journal Cell.

The DREAM gene was already known to be involved in suppressing

dynorphin, an opioid the body naturally produces in response to pain.

The DREAM gene basically ``sits on'' the dynorphin gene in the spine to

control the opioid's production, said f M. Penninger of the Amgen

Institute and the University of Toronto in Canada.

But his team found that knocking out the DREAM gene in mice allowed

greater production of dynorphin in the spine.

As a result, the animals' responses to a range of painful stimuli--from

acute stresses like heat to simulations of chronic pain like arthritis

and back pain--were greatly inhibited.

Penninger said it may be possible to ease the chronic pain that marks

diseases such as cancer and arthritis by inhibiting DREAM function. What

is ``intriguing'' about the current findings, he noted, is that the

gene's action was specific to the spinal cord. Mice that lacked the gene

showed no changes in the heart, brain and immune-system functions the

scientists measured.

This, according to Penninger, suggests it is feasible to alter DREAM

function to fight pain without creating significant side effects. By

contrast, he said, simply administering dynorphin does affect heart,

brain and immune function.

On the other hand, Penninger said, the fact that side effects did not

occur in the mice does not mean the same will be true of humans. In

addition, the DREAM gene inhibits dynorphin production for a reason: we

need to feel pain to a certain extent--to prevent burning a hand on a

hot surface, for example.

Researchers must better understand the consequences of blocking DREAM

function before it can be used to treat chronic pain, Penninger added.

SOURCE: Cell 2002;108:31-43.