Story Source: Thomas Klein, PhD, 813-974-2502
Media Contact: Anne DeLotto Baier,
USF Health Sciences, 813-974-3300
USF RESEARCHER: STUDY OF CANNABINOID RECEPTOR SYSTEM SHOWS THAT MARIJUANA ALTERS IMMUNITY AS WELL AS MOOD
TAMPA, Fla. (June 11, 1997) ã In Dr. Thomas Klein's crowded laboratory office, beneath the shelves of scientific journals and texts, hangs a preserved puffer fish with an imitation joint dangling from its mouth.
Even the ancient blowfish has been found to harbor chemical receptors that react to delta-9 tetrahydrocannabinol, or THC, the compound in marijuana that produces a high, said Dr. Klein, professor of medical microbiology and immunology at the University of South Florida.
"It's fascinating," he said. "Why would both humans and this fish evolve with the genes for a receptor that would only be activated if you smoked marijuana? Conservation through evolution suggests that the gene is important.
"We now know there's a substance circulating in the body called anandamide that binds to cannabinoid receptors. So there's definitely a physiological role for endogenous cannabinoid receptors, possibly in behavior modification or defining moods as well as regulating immunity and other functions."
Dr. Klein is a pioneer in the new field of psychoneuroimmunology. In the laboratory, he studies the physical links between drugs of abuse and the brain, emotions and immunity.
Supported by a $674,000 National Institutes of Health grant, he and his colleagues are one of few scientific groups in the world investigating the distribution and function of cannabinoid (marijuana) receptors in the immune system. Cannabinoid receptors have also been found in the brain, the gut and the reproductive system. Cells imbedded with these receptors are inhibited from functioning when exposed to the THC molecule.
Pot's influence on the immune system continues to be hotly debated within the medical community. Animal and human studies have demonstrated that virtually every immune function, from antibody production to the destruction of invading microorganisms, is suppressed by relatively high concentrations of marijuana. In those whose immune responses are already poor, Dr. Klein said, marijuana may aggravate deteriorating health.
"It's believed to be a rather benign drug, effective in reducing pain and nausea," Dr. Klein said, "but scientific evidence is accumulating, through the study of the cannabinoid receptor system, that THC might affect almost every cell in the body.
"People need to know that if they smoke marijuana, they are not just altering their moods. They're altering their immune systems." Scientists may know more about marijuana's hazards or benefits to health once they understand how the cannabinoid system fits into the body's complex network of immune regulation.
Dr. Klein suspects that the natural purpose of cannabinoid receptors may be to control more powerful immune systems serving as the body's first line of defense against infection or tumors. "The horse gets the buggy started, but the cannabinoid system is like the driver with the whip who keeps things going," he said.
A recent study by USF's Dr. Klein, Herman Friedman, PhD, and others demonstrated that cannabinoid receptors play an important role in the increased production of the protein NF-kb in immune cells exposed to THC. The results, published in the journal DNA and Cell Biology, suggest that marijuana may accelerate AIDS development by increasing NF-kb, which is known to rev up replication of the AIDS virus.
The researchers emphasize the need for further investigation of cannabinoids and other drugs of abuse as co-factors in disease.
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