MARIJUANA-LIKE CHEMICALS COULD TREAT DISEASE

WASHINGTON (Reuters) - A marijuana-like chemical in the brain that
helps regulate body movement and coordination might be used to treat
diseases that produce tics and shaking, such as Parkinson's disease
and schizophrenia, researchers said.

University of California Irvine researchers found that the chemical,
known as anandamide, acts as a kind of brake on neural activity in the
brains of rats, and might be used to treat the side-effects of
diseases that cause uncontrollable movements.

Writing in the April issue of the journal Nature Neuroscience, they
said anandamide interferes with the effects of nerve cells that
transmit dopamine, the message-carrying chemical responsible for
stimulating movement and other motor behavior in the brain.

Uncontrolled production of dopamine has been blamed for some of the
symptoms of schizophrenia and the nervous tics and outbursts
associated with Tourette's syndrome. A lack of dopamine is blamed for
the shaking and motor hesitation that marks Parkinson's disease.

``This shows for the first time how anandamides work in the brain to
produce normal motor activity,'' Daniele Piomelli, an associate
professor of pharmacology at UCI who helped lead the study, said in a
statement.

``Patients with schizophrenia and other diseases have reported that
marijuana appears to relieve some of their symptoms, but scientists
have never found a physiological reason why. By understanding how the
anandamide system works similarly to marijuana, we can explore new
ways to treat these diseases more effectively.''

But Piomelli said cannabis itself did not offer any kind of cure.
``Marijuana doesn't provide the regulatory effects on dopamine in the
brain that we're looking for,'' he said.

Anandamide, named after the Sanskrit word for ``bliss and
tranquillity,'' is used by a network of nerve cells in an area of the
brain called the striatum, which coordinates body movements and other
motor behavior, the researchers said.

Normally nerve cells regulate this behavior by releasing anandamides
at the same time they release dopamine. The anandamides bind to
cannabinoid receptors, which are where tetrahydrocannabinol (THC), the
active ingredient in marijuana, docks onto cells.

When the team blocked these receptors, rats experienced severe nervous
tics and other uncontrolled motor activity.

Piomelli said new drugs that mimic the effects of anandamides could
offer gentler treatments for some diseases.

``Current drugs certainly halt the actions of dopamine, but the side
effects, including sedation and dizziness, are very severe,'' he said.

In a commentary, David Self of Yale University said the approach could
be used to develop drugs that help Parkinson's treatments, which try
to boost production of dopamine in the brain but whose effects wear
off after a few years.

Drugs that stimulate the cannabinoid receptor might also be used
against Huntington's disease, a fatal and incurable disease first
marked by jerks and spasms, Self added.