MARIJUANA CHEMICAL TAPPED TO FIGHT STROKES

The breakfast table may someday feature not only orange juice and vitamins
but also a more exotic health booster-a compound extracted from marijuana.

Cannabis contains a chemical that can protect cells by acting as an
antioxidant, a new study shows. More effective than vitamins C or E, it
offers an appealing option for the treatment and perhaps prevention of
stroke, neurodegenerative diseases, and heart attacks, the researchers
suggest.

However, there's no worry that those who take it will become too stoned to
read the morning paper. The compound, called cannabidiol, doesn't make
people high.

Scientists have yet to test whether the chemical has a protective effect in
people. In test-tube experiments, researchers at the National Institutes of
Health (NIH) in Bethesda, Md., exposed rat nerve cells to a toxin that is
typically released during strokes. Cannabidiol reduces the extent of
damage, the scientists report in the July 7 Proceedings of the National
Academy of Sciences.

In follow-up studies, the researchers induced strokes in rats and treated
them with cannabidiol. Those experiments are not yet complete, but "we're
getting some good results," says Aidan J. Hampson, an europharmacologist at
NIH.

Researchers suspect that many antioxidants can reduce the severity of
ischemic strokes, in which blood vessels in the brain become blocked.
During ischemic strokes, which make up 80 percent of all strokes, a toxin
initiates the release of reactive oxygen molecules called free radicals
into the bloodstream. These harmful molecules are under suspicion as one of
the agents that cause stroke damage, such as paralysis and loss of speech
and vision. Antioxidants such as cannabidiol neutralize free radicals and
so might limit the damage.

The NIH researchers had suspected that the group of molecules including
tetrahydrocannabinol (THC), the marijuana ingredient that produces a high,
would act as antioxidants. In their study, THC and cannabidiol provided
equal defense against cell damage. An earlier study at the University of
Arizona in Tucson turned up no side effects of cannabidiol in people given
large doses.

A pharmaceutical company, Pharmos in Rehovot, Israel, is already conducting
human clinical trials using a synthetic marijuana derivative, Dexanabinol,
to treat damage from strokes and brain injury. Like cannabidiol, this
compound is an antioxidant and does not produce euphoria.

"This is a promising area [of research] . . . particularly because we have
so few effective means of treating stroke," said JoAnn E. Manson, a
researcher in preventive medicine at Harvard Medical School. Stroke is the
third leading killer in the United States (SN: 12/21&28/96, p. 388).

The NIH researchers don't anticipate using cannabidiol to treat hemorrhagic
stroke, characterized by bleeding within the brain, Hampson says.
Antioxidants, however, could help treat other diseases that appear to be
caused in part by free radicals. These include heart disease and two
neurodegenerative disorders, Alzheimer's disease and Parkinson's disease.

From Science News, Vol. 154, No. 2, July 11, 1998, p. 20. Copyright 1998 by
Science Service.

References:

Hampson, A.J., et al. 1998. Cannabidiol and tetrahydrocannabinol are
neuroprotective antioxidants. Proceedings of the National Academy of
Sciences 95(July 7):8268.

Further Readings:

Lipkin, R. 1994. Protecting nerve cells after injury. Science News
146(Sept. 3):157.

Raloff, J. 1996. Antioxidants: Confirming a heart-y role. Science News
150(July 6):6.

Seachrist, L. 1995. Widely used drug prevents stroke. Science News
148(Sept. 16):183

Sternberg, S. 1996. Bold aim in stroke: Spare the brain. Science News
150(Dec. 21):388.

Sources:

Aidan J. Hampson National Institutes of Health National Institute of Mental
Health Laboratory of Cellular and Molecular Regulation Bethesda, MD 20892

JoAnn E. Manson Harvard Medical School 181 Longwood Avenue, Room 333
Boston, MA 02115

copyright 1998 ScienceService

Checked-by: Mike Gogulski