ARTIFICIAL POT-LIKE CHEMICAL MAY EASE PAINS

A synthetic version of the chemical that gives marijuana smokers their
high can also cool the "heat" of an injury. That makes it a potential
new pain reliever for surgical incisions, infections and chronic
inflammation disorders such as arthritis, San Antonio researchers say.

Scientists at the University of Texas Health Science Center found that
certain synthetic cannabinoid chemicals can block a heat-related nerve
channel in the body.

It's the same pathway that the body uses to feel the spice of hot
peppers and the zing of pepper spray, said Kenneth M. Hargreaves,
chairman of endodontics in the university's dental school and lead
author of the study.

By altering the cannabinoid and using it in tiny doses, scientists
appear to be able to avoid the neurological effects of marijuana, he
said.

"This is one of the major receptors our body uses to detect heat and
detect a lot of different chemicals," Hargreaves said. "This offers
the promise of developing an entirely new generation of drugs that
have the beneficial effects of marijuana -- that is pain relief --
without having any of the side effects that marijuana is notoriously
known for."

The study will appear this week on the online site of the Proceedings
of the National Academy of Science. It also will appear in the July 25
print issue of the scientific journal.

In their first experiments, the San Antonio scientists injected the
cannabinoid compound into inflamed tissue of rodents and observed
"really potent" pain relief, Hargreaves said.

Next, they took tissue samples to the lab to try to understand how the
relief occurred, and they discovered that the cannabinoid switches off
a capsaicin receptor called TRPV1.

"What we envision is, with this knowledge we can develop drugs that
you can take as a pill and would only act in the periphery" and not in
the brain, Hargreaves said.

Scientists now are going back to the dental lab to investigate how
inflamed human dental tissues will respond, said Amol M. Patwardhan, a
scientist who works under Hargreaves.

"If it works there, then we might actually be able to try it in
clinical trials, where we can inject it into inflamed dental pulp,"
Patwardhan said.