How to Use Cannabis Responsibly and Safely The Experience of Getting High
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The Baltimore Sun (MD), 2004-11-09 (Tues) Marijuana-like drugs are potent field of inquiry by David Kohn
A decade ago, when Daniele Piomelli went to scientific conferences, he was
often the only researcher studying cannabinoids, the class of chemicals
that give marijuana users a high.
His work often drew snickers and jokes -- but no more. At the annual
Society for Neuroscience conference two weeks ago, scientists here
delivered almost 200 papers on the subject.
Why the attention? Many scientists believe marijuana-like drugs might be
able to treat a wide range of diseases, far beyond the nausea and chronic
pain typically treated with medical marijuana.
Researchers at the conference presented tantalizing evidence that
cannabinoid drugs can help treat amyotrophic lateral sclerosis, known as
ALS or Lou Gehrig's disease, Parkinson's disease and obesity. Other
researchers are studying whether the compounds can help victims of stroke
and multiple sclerosis.
Although the chemicals work on the same area of the nervous system, the new
drugs are much more refined and targeted than marijuana, with few of its
side effects.
RANGE OF POTENTIAL
''Cannabinoids have a lot of pharmaceutical potential,'' said Piomelli, a
neuroscientist at the University of California, Irvine. ``A lot of people
are very excited.''
Although the federal government opposes the use of medical marijuana, it
generally doesn't restrict cannabinoid research, most of which doesn't
involve the cannabis plant itself. Scientists who use Marinol, a legal but
tightly regulated marijuana-like drug, do need government permission.
Because the cannabinoid system wasn't discovered until the late 1980s --
decades after serotonin, dopamine and other neurotransmitters --
researchers still know relatively little about how it works.
Like all neurotransmitter networks, the cannabinoid system consists of a
series of chemical pathways through the brain and nervous system. Marijuana
produces its effects by activating this pathway, primarily through the
effects of tetrahydrocannabinol, or THC, the drug's main active ingredient.
Over the past decade, researchers have been following these abundant trails
to determine their real purpose.
''You don't have them there to get stoned. So there must be internal
reasons,'' said Andrea Giuffrida, a neuroscientist at the University of
Texas Health Sciences Center in San Antonio.
Researchers have learned that endogenous cannabinoids -- internal brain
chemicals that activate the system -- play a role in tissue protection,
immunity and inflammation, among other functions. The cannabinoid system
also appears to exert wide influence, modulating the release of dopamine,
serotonin and other neurotransmitters.
Giuffrida and others believe cannabinoids can treat degenerative disorders
such as Parkinson's disease and ALS.
At the conference, Giuffrida announced that a cannabinoid drug wards off
Parkinson's-like effects in mice.
The disorder, which afflicts more than 1 million Americans, destroys
neurons in a key part of the brain, causing patients to lose control over
movement.
Giuffrida, with colleagues David Price and James Roberts, injected mice
with a chemical called MPTP, which mimics Parkinson's damage. When some of
the animals subsequently received a drug that blocks cannabinoid receptors,
their nerve cells suffered far less damage than did the cells of the other
mice. This was the first demonstration that a cannabinoid drug can have
this effect.
While he is not sure how the anti-cannabinoid compound works, Giuffrida
suspects it protects neurons by reducing inflammation, a key component in
Parkinson's.
Cannabinoids might also slow down ALS, which destroys neurons that control
muscles until victims become paralyzed, unable to breathe on their own.
ANIMAL EXPERIMENTS
Neuroscientist Mary Abood first became interested in cannabinoids after
hearing about ALS patients who got some relief from smoking marijuana. So
she began animal experiments at the California Pacific Medical Center in
San Francisco.
In her study, mice with a variant of ALS were given a combination of THC
and cannabidiol, another compound found in marijuana. Both substances are
cannabinoid agonists, chemicals that activate the cannabinoid system.
The treatment delayed disease progression by more than seven days and
extended survival by six days. In human terms, this would amount to about
three years. That's a significant improvement over the only existing ALS
drug, riluzole, which extends life by two months.
Also at the conference, researchers at the Institute of Neurology in London
announced results that corroborated her findings. Cannabinoids have also
helped some human ALS patients in one small trial.
If cannabinoids can shield human neurons from harm, researchers say, they
might prove useful against other neurological diseases, including mental
illness. Scientists are looking at whether cannabinoids can treat multiple
sclerosis, epilepsy and Huntington's disease, while Giuffrida is beginning
a study of their effect on schizophrenia.
Advocates of medical marijuana have long argued that the drug can be useful
for treating many conditions, particularly chronic pain, nausea and
glaucoma (in the latter, marijuana works by temporarily decreasing pressure
around the eye).
Although they don't dispute this view, most researchers believe there are
better, more precise ways to stimulate the cannabinoid system. They believe
marijuana has too many negatives to be a truly effective drug, with side
effects that include memory problems, decreased immunity and possibly
addiction.
Pubdate: Mon, 01 Nov 2004 © 2004 The Baltimore Sun, a Times Mirror Newspaper |
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