Most of us probably take for
granted that physical pain —
whether it be from a sports
injury, a kidney stone or appendicitis
— can be attributed to some form
of inflammation and that it will end.
Neuropathic pain, however, affords its
sufferers no such luxuries. It’s chronic
and unrelenting, and its cause is
unknown, making treatment difficult.
It turns out that neuropathic pain is
triggered when the body experiences
endoplasmic reticulum (ER) stress, a
condition in which the production and
transport of protein exceeds the cells’
capacities, say researchers from the
University of California, Davis. Because
diabetics are at high risk of having
neuropathic pain, the team studied
diabetic rats that had neuropathic
symptoms: hypersensitivity to touch
and lack of heat sensation. And the
rats’ nerve cells showed clear signs
of ER stress.
When the researchers treated the
rats with a compound that blocks ER
stress, the pain symptoms disappeared.
Conversely, healthy rats developed neuropathy
when they received chemicals
that induce the stress response.
“Medications have historically
focused on turning down the nerve
response to pain, but now we’ve found
one way to block the stress signal
that generates the pain,” says Bruce
Hammock, corresponding author of the
study, which was published in July.
While it usually takes years for
a discovery to translate to new
medication, there may be a shortcut in
this case. A medication that blocks ER
stress is already on the market to treat
an entirely different condition called
urea cycle disorder. It would take a
horse pill of the current medication to
quell neuropathic pain, Hammock says,
but the compound has promise.