POT-LIKE DRUG COULD BE THE 'NEXT PROZAC'

Eases Anxiety...In Rats

SASKATOON - A University of Saskatchewan team has shown a pot-like
drug reduces the symptoms of anxiety and depression in rats.

Using injections of a synthesized substance called HU210, which
mimics one of the active ingredients in marijuana, associate
professor of psychiatry Dr. Xia Zhang and his colleagues showed new
growth of brain cells increased in rats.

Other recent studies have linked that growth, or so-called
neurogenesis, to a reduction in anxiety and depression.

The results were published yesterday on the Web site of the Journal
of Clinical Investigation.

"The implication of this paper is that smoking marijuana is a good
thing," Dr. Zhang said with a hearty laugh in his Saskatoon office.

Well, good for rats anyway.

"We hypothesize cannabis or marijuana can produce a similar effect,"
Dr. Zhang said.

The group, including researchers at Xijing Hospital in China and at
the University of Maryland in Baltimore, have yet to test the effect
of marijuana itself on rats' neurogenesis, Dr. Zhang said.

He also cautions against the assumption the drug will have the same
effect on humans.

"There is a big gap between rats and humans," Dr. Zhang said.
"Realistically, we cannot judge these results from rats and apply
them to a human situation. There's a huge difference. Our results can
give [only] some indication or implication."

Although previous studies have shown alcohol, nicotine, opiates and
cocaine reduce the growth of new brain cells, Dr. Zhang's paper is
the first to show marijuana could have the opposite effect.

Because rats can not say how depressed they are, researchers used
tests like putting the rats in a swimming pool with no escape to see
how quickly they would give up swimming and resign themselves to a
likely fate of drowning. (The rats were plucked out of the pool
before they could drown).

What is more exciting to researchers than the potential connection
between smoking pot and easing lethargy and frayed nerves is the
possibility a component of marijuana could be the next blockbuster
anti-depressant.

"Prozac is great, but it does have its problems, and its mechanism of
action is similar to antidepressants we were using 40, 50 years ago,"
said Dr. Lisa Kalynchuk, a Canada Research Chair in behavioural
neuroscience and associate professor of psychology at the University
of Saskatchewan. "What we really need in the field is to develop new
anti-depressant drugs that are acting in new ways. Certainly, if we
could get a drug that would act on these [cannabis] receptors and
could actually alleviate depressive symptoms, that would be
fantastic. It would be the next Prozac -- the next company to make
billions of dollars."

There are problems with antidepressants currently on the market, she
said, including side effects like dizzy spells, insomnia and impaired
sex drive.

Some drugs take a month to start working and others don't work on
some people at all, she said.

But researchers would have to develop a better understanding of the
mechanism by which HU210 or cannabis work in the brain before they
package them into pills, Dr. Zhang said.

Dr. Kalynchuk also questions whether the cannabis-like drug would
have an effect on anxiety, since only one major study has shown a
connection between increased neurogenesis and the reduction of anxiety.