Monday, July 31 (HealthSCOUT) -- A punchless part of pot could offer arthritis patients a reprieve from their inflamed and painful joints.

British and Israeli researchers say arthritic mice treated with a nonintoxicating component of marijuana showed significant improvement in several key signs of their disease.

The notion that marijuana helps arthritis is far from novel. Indeed, the Chinese recorded the drug's healing properties for rheumatism some 4,000 years ago.

Marijuana contains roughly 80 active chemicals called cannabinoids. Tetrahydrocannabinol, or THC for short, has mind-altering properties that give users their high. Other components, however, appear to have therapeutic powers -- from soothing pain and nausea to calming spastic muscles -- but produce no brain changes.

Although recreational use of pot is illegal in the United States, several states -- including California, Hawaii, Alaska and Oregon -- have laws that permit medical uses of the drug. The federal government, however, staunchly has maintained its opposition to such policies.

Between penal codes and pro-pot advocates lies a cloudy field of science. A 1999 report from the National Academies Institute of Medicine found that cannabinoid drugs, and primarily THC, the active compound in marijuana, may be good for pain relief, control of nausea and vomiting and appetite stimulation.

Other researchers, however, have focused on the drug's downside, which includes the potential to cause head and neck tumors, to damage cells in the lung lining and even to trigger heart attacks.

The latest study, by scientists at Hebrew University in Jerusalem and the Kennedy Institute of Rheumatology in London, tested both injections and oral doses of the cannabinoid CBD in mice with collagen-induced arthritis, a joint disease that mimics human rheumatoid arthritis.

The drug, a precursor of THC, had a Goldilocks effect: Neither small nor large amounts of either form were effective, but a middle dose shielded joints from damage, the researchers say. A report on their findings appears in the latest issue of the Proceedings of the National Academy of Sciences.

Tests of the animals' lymph fluid showed that the marijuana compound suppressed activity of immune cells and molecules, the researchers say. It also reduced inflammation in joint tissue, particularly by quelling the production of tumor necrosis factor, a potent chemical involved in swelling.

The researchers repeated their study in mice with homologous CIA, a form of recurring arthritis that more closely resembles what humans contract. And again, the marijuana compound showed significant joint protection.

The study suggests that CBD could help arthritis patients "and may be valuable in the treatment of other chronic inflammatory diseases as well," the scientists say.

Dr. John Morgan, a professor of pharmacology at City University of New York Medical School in Manhattan, and an expert in the medical uses of marijuana, says the latest research is neither surprising nor new.

"Both [CBD and THC] have anti-inflammatory properties in some animal systems," he says. But Morgan also cautions that animal studies, including the Israeli work, typically rely on doses far greater than most people take.

Dale Gieringer, coordinator of the California chapter of NORML, a national pro-pot group, says between 10,000 and 20,000 Californians use marijuana medicinally, most for chronic pain linked to cancer, AIDS and arthritis.

http://www.canorml.org/

Yet the true therapeutic potential of marijuana won't be clear until it is studied in a rigorous, scientific manner, Gieringer says. And those studies, at least in the United States, aren't on the horizon.

"We're not really a free country when it comes to drug research," Gieringer says.

Steven Gust, special assistant to the director of the National Institute on Drug Abuse, which funds marijuana research, says the idea that the government is squashing pot studies is misguided.

"The fact is that we're not getting requests and we're not getting proposals," Gust says. The National Institutes of Health is sponsoring three trials to test the clinical benefits of the drug, including one in California involving AIDS patients, Gust says.

Morgan, however, says basic marijuana research in this country almost exclusively involves animals, not people. As a result, he says, the best hope for good trials of the therapeutic potential of the drug lies in Europe and Australia, where the scientific climate is more tolerant of the drug.

What To Do:

The only government-approved synthetic marijuana compound is dronabinol, or Marinol, which eases the nausea and pain of cancer treatments.

To read more about the potential medical uses of marijuana, visit the Institute of Medicine, or check out information provided by Harvard University.

http://www.nap.edu/readingroom/books/marimed/