WEDNESDAY, Oct. 18 (HealthDay News) -- A new U.S. study finds that marijuana may help slow the progression of Alzheimer's disease, while a second report suggests the "club drug" Ecstasy could yield insights into Parkinson's disease.

Both findings were presented Wednesday at the annual meeting of the Society for Neuroscience, in Atlanta.

In the first presentation, researchers from Ohio State University in Columbus found that marijuana may contain compounds that can slow memory loss associated with Alzheimer's disease.

In their study involving rats, a team led by psychology professor Gary Wenk searched for ways to reduce Alzheimer's-linked brain inflammation.

Wenk was already familiar with data that found that long-term marijuana users had lower rates of Alzheimer's disease than the general population. His team sought to find a compound that might reduce disease-linked brain inflammation but avoid the drug's psychoactive effects.

"We are using a component of marijuana that stimulates the same centers in the brain that marijuana does," Wenk said. The synthetic compound, which is very similar in composition to marijuana, is called WIN-55212-2 (WIN).

Experiments conducted on young and old rats revealed that WIN is "a very effective anti-inflammatory, it reduces brain inflammation," Wenk said.

What makes this discovery special is that this compound can cross the blood-brain barrier, Wenk explained. The results of a special rat "maze test" suggested that WIN "also reversed the memory impairment in the older rats," he said.

Brain inflammation is characteristic of many diseases other than Alzheimer's, including multiple sclerosis, ALS, AIDS, Huntington's and Parkinson's, Wenk noted. "We are beginning to notice that brain inflammation is always in the background as people get older," he said. "Inflammation doesn't cause the disease, it contributes to the pathology," he said.

WIN is not appropriate for use in humans because it still contains substances that may trigger a "high." However, Wenk hopes that some form of this compound might be used to benefit people with neurological diseases.

"We have the added advantage that millions of doses [of marijuana] have been taken by millions of people over the past centuries," he said. "We already know a lot about its actions in the body and its toxicity, or lack of toxicity. The only problem we have is that it's illegal."

Wenk is not suggesting that Alzheimer's patients start using marijuana. "Patients would have to be so careful not to get too much," he said. "That would only worsen the symptoms of their dementia."

The challenge is to find a dose that has an anti-inflammatory effect but does not make patients high, Wenk said. "It's hopeful," he said, "but it's not a therapy until we find a way to make it work in humans."

One expert believes it may be possible to derive therapeutic benefits from marijuana without inducing other effects that could be harmful to Alzheimer's patients.

"These are still early days for thinking about drugs derived from cannabis," said Dr. Samuel Gandy, director of the Farber Institute for Neurosciences at Thomas Jefferson University in Philadelphia.

"Still, we know the structure of tetrahydrocannabinol (THC) [the active ingredient in cannabis] in detail, and it is not inconceivable that helpful THC-based drugs could be created chemically that benefit brain function but lack the 'high' that currently stigmatizes the compound," Gandy added.

In the second report, researchers from the University of Cincinnati found that, in rats, MDMA (methylenedioxymethamphetamine) -- more commonly known as the illegal drug Ecstasy -- increases the survival of dopamine-releasing cells in the brain during fetal development.

"The club drug Ecstasy can cause dopamine neurons to grow and prevent them from dying off," explained lead researcher Jack Lipton, a professor of psychiatry.

Dopamine cells are critical to the regulation of voluntary movement. This discovery might lead to better therapies for neurological diseases such as Parkinson's, the researchers said.

Ecstasy, as is, is not beneficial for Parkinson's patients, Lipton cautioned. But a part of MDMA may be.

The trick now is to find the components of MDMA that have this effect on dopamine cells and develop ways to use it to help Parkinson's patients, Lipton said. It could also be used as an adjunct to stem cell transplantation, something that's now being studied in Parkinson's patients.

"It could help transplants take better and have more cells survive," Lipton said.

More information

There's more on Alzheimer's disease at the Alzheimer's Association.

SOURCES: Gary Wenk, Ph.D., professor, psychology, Ohio State University, Columbus; Jack Lipton, Ph.D., professor, psychiatry, University of Cincinnati; Samuel Gandy, M.D., Ph.D., director, Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia; Oct. 18, 2006, presentations, Society for Neuroscience annual meeting, Atlanta

Last Updated: Oct. 18, 2006

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