TESTS SHOW CANNABIS CAN HELP WITH MS

Campaigners who want cannabis to be legalised for medicinal purposes
received a boost yesterday, writes Jennifer Trueland.

Scientists showed for the first time that an ingredient in the drug
reduces some of the most distressing symptoms of multiple sclerosis.
People with MS have long claimed that smoking the drug helps the
symptoms of the disease but have found themselves on the wrong side of
the law.

The evidence that it helps multiple sclerosis sufferers and those with
other conditions such as glaucoma has until now been anecdotal. The
government has agreed that clinical trials should be carried out, but
the results are not expected for two years.

The first of these Medical Research Council trials has just started,
but work from a British team of scientists suggest that the results
may well be positive.

The researchers, from the Institute of Neurology at University College
London, reported that a psychoactive compound in cannabis can prevent
muscle tremor and spasticity caused by MS. They also demonstrated that
synthetic chemicals mimicking the compound have a similar effect,
pointing the way to the development of new pharmaceutical drugs.

On Monday, a separate team of Spanish scientists showed that the same
active ingredient, tetrahydrocannabinol (THC), destroys malignant
brain tumours in laboratory rats.

The scientists say the most significant outcome may be a move away
from cannabis to designing artificial drugs.

The researchers used mice given an animal equivalent of MS which
produces the same disease pattern and symptoms seen in humans.

Someone with MS typically suffers a series of episodes of paralysis,
with periods of remission in between. As the disease progresses
spasticity, or muscle rigidity, and severe tremors may appear which
can have a devastating effect on the sufferer's quality of life.

In the study mice were injected with the cannabinoid THC as well as
three synthetic compounds. One, methanandamide, was similar to a
cannabinoid produced naturally in the body. All had a significant
ability to reduce both tremor and spasticity. A synthetic compound
called WIN55 proved the most effective.

Dr David Baker, one of the UCL scientists, said: "The effect was
really startling. It was a question of now you see the tremor, now you
don't."

The targets for the compounds were two cannabinoid receptors - docking
points where molecules of the right shape interlock and produce
biological effects - found in the brain and spinal cord.

Blocking the receptors with other chemicals not only prevented the
therapeutic action of the compounds, but made the existing symptoms
worse.

The scientists concluded that a natural control mechanism was being
interfered with as well as the effect of the compounds. This suggested
that the purpose of the receptors - and the natural cannabinoid which
bound on to them - was to maintain motor control.