CANNABIS MAY EASE MS SYMPTOMS

British Mice Experiments Point Way To New Multiple Sclerosis Drugs

Cannabis may improve the symptoms of multiple sclerosis, experiments on
mice have shown. There have been many anecdotal reports of benefits from
MS sufferers who have taken cannabis illegally, but scientific evidence has
been lacking. Now a team led by David Baker of the Institute of Neurology
in London has shown that in a strain of mice which suffer a similar
disease, the active agents in cannabis reduce rigidity and trembling of the
muscles.

The team also found that synthetic chemicals mimicking tetrahydrocannabinol
(THC), an active chemical in cannabis, had a similar effect, pointing the
way to new drugs to treat MS.

The results will boost calls to legalize cannabis for medical use. But the
scientists say their main result may be a move from cannabis to related
synthetic drug as that are even more effective.

The mice were injected with THC and three other compounds: methanandamide,
similar to a cannabinoid produced naturally in the body, and two synthetic
compounds. All reduced both tremor and spasticity (rigidity), but a
synthetic compound called WIN55 proved the best against tremors, halting
uncontrolled limb movements in as little as a minute. Baker said, 'The
effect was really startling. It was a question of 8CNow you see the
tremor, now you don't.' '

The compounds lock on to two receptors in cells of the brain and spinal
cord. Blocking the receptors not only prevented the therapeutic action of
the compounds but made the existing symptoms much worse.

The scientists conclude in an article in the science journal Nature that
the purpose of the receptors and the natural chemicals that bind to them is
to maintain control of the muscles, Baker said. `One of their functions is
to provide a protective filter mechanism to limit excess excitation of the
nerves. In a normal animal or human being it provides fine control over
motor function.'

One implication of the research is that it may be possible to increase
levels of the natural cannibinoid, in the same way that anti-depressant
drugs lift the levels of chemicals in the brain linked to mood.

Additionally, the same receptors are found in the pain centres of the
spinal cord. That may explain the claimed benefits of cannabis for pain
relief.

Lorna Layward of the British Multiple Sclerosis Society, who co-authored
the report, said there was a `crying need' for new drugs for MS because
current treatments were either not very effective or caused severe side
effects. Tremor was particularly difficult to treat and could be severely
disabling, she said.

A clinical trail by British Medical Research Council is examining the
effect of cannabis and THC on spasticity in 600 MS patients.

It will report in two years.