Study: Drug reduces brain inflammation found in Alzheimer's -- Misti Crane THE COLUMBUS DISPATCH (October 19, 2006) -- Give an old, confused rat some pot and it starts remembering things.

An Ohio State University study shows that synthetic marijuana boosted memory and reduced brain inflammation in rats with brains altered to mimic the effects of Alzheimer's disease.

Researcher Gary Wenk, a study co-author and Ohio State professor, shared his work at the Society for Neuroscience meeting in Atlanta this week.

The findings support the theory that anti-inflammatories might help fight the devastating disease and add to evidence that compounds in pot might be helpful in treating Alzheimer's, Wenk said.

While research showing the benefits of marijuana in multiple sclerosis cases has been advancing significantly, work in Alzheimer's disease is still in its infancy.

"We need much more evidence," Wenk said.

The test animals in Wenk's study were given WIN, a synthetic drug similar to marijuana.

Rats that had the drug and rats that didn't were given three days to repeatedly navigate a water maze with an escape route.

On the fourth day, Wenk and his colleagues timed the rats.

In general, old rats are bad at navigating mazes.

But those given pot had a 50 percent improvement in memory and a 40 to 50 percent reduction in brain inflammation, Wenk said.

"If we can cut their impairment in half, that's amazing in an old animal," he said.

"Old" in the rat world is about 24 months. Young rats' memories also improved with the drug, but not as significantly.

Neither marijuana nor the synthetic substitute is a good candidate for humans, Wenk said.

"When you're in your 60s, you don't want to get high, you just want to prevent dementia," he said.

"Our challenge is to find a modified (drug) that is going to be an effective anti-inflammatory, but not make the patients high."

Brain inflammation isn't the cause of Alzheimer's disease, but it appears to play a significant role, said Wenk, who has studied the disease for two decades.

A recent study performed at the Scripps Research Institute in California found that THC, the active ingredient in marijuana, inhibits the formation of a brain plaque that is a hallmark of Alzheimer's disease.

Researchers there said they were not advocating recreational drug use but had convincing evidence that marijuana had "remarkable" qualities compared with available medications.

In another study, Spanish researchers also found that rats given synthetic marijuana performed better on mental-function tests, leading them to conclude that the drug worked to prevent inflammation and protect the brain.

A handful of current treatments for Alzheimer's work by preventing the breakdown of a chemical thought to be important to memory and thinking.

Another medication works by regulating glutamate, a brain chemical that can lead to braincell death when produced in excess.

The two often are used in conjunction, but they are limited in their effectiveness, Wenk said.

"We're focusing on trying to find ways to maybe attack the other parts of the disease," he said.

An estimated 4.5 million Americans have Alzheimer's disease and that number could almost quadruple by 2050, according to the Alzheimer's Association.

As for whether smoking marijuana has any benefit, that's something that will take some time to sort out - at least as long as it takes for the regular smokers of the 1960s and '70s to age and for scientists to sort out whether the pleasures of their youth brought good things in their golden years, Wenk said.

"Yes, millions of people have used marijuana, but they're not old enough to be at risk."

mcrane@dispatch.com