MARIJUANA-LIKE DRUG LESSENS ANXIETY IN RATS

A University of Sask-atchewan team has shown a marijuana-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 cannabis, 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 Thursday on the website of the Journal of
Clinical Investigation.

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

Well, good for rats anyway.

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

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, 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," 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, Zhang's paper is the
first to show marijuana could have the opposite effect.

Because rats can't say how depressed they are, researchers used tests
such as putting the rats in a swimming pool with no escape to
determine 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's 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
antidepressant.

"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 U of S.
"What we really need in the field is to develop new antidepressant
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."