CANNABIS MAY BECOME 'THE ASPIRIN OF THE 21ST CENTURY'

Cannabis, the third most popular recreational drug after alcohol and
tobacco, could win a new role as the aspirin of the 21st century, with
growing evidence that its compounds may protect the brain against the
damaging effects of ageing.

Although the drug distorts perception and affects short-term memory, it may
also help prevent degenerative diseases such as Alzheimer's, Parkinson's,
Huntingdon's and motor neurone diseases. Scientists at the Institute of
Neurology in Queens Square, London, say the "huge potential" of cannabis
compounds is emerging, as understanding of its biological and
pharmacological properties improves.

Professor Alan Thompson and his colleagues wrote in Lancet Neurology:
"Basic research is discovering interesting members of this family of
compounds that have previously unknown qualities, the most notable of which
is the capacity for neuroprotection."

The results of two trials in patients with multiple sclerosis are expected
this summer and the first cannabis-based medicines are being considered for
licensing. None of them will have the psychoactive properties of the raw
drug when smoked or ingested.

Professor Thompson's team says: "Even if the results of these studies are
not as positive as many expect them to be, that we are only just beginning
to appreciate the huge therapeutic potential of this family of compounds is
clear."

Cannabis was thought to affect the cells like alcohol by seeping through
the cell membrane. But in 1990 the first cannabinoid receptor was found,
which revolutionised the study of cannabinoid biology. The discovery
revealed an endogenous system of cannabinoid receptors, similar to the
opioid system, to which the drug bound when it was ingested. Just as
endorphins are the body's natural equivalent of heroin, a fatty acid called
anandamide (Sanskrit for "inner bliss") is the natural equivalent of cannabis.

The natural system of cannabinoid receptors plays a role in maintaining the
balance of chemicals in the brain which regulate the rate at which neurons
fire. By altering this system, scientists believe it may be possible to
slow or prevent the process of brain decay. David Baker, lead author of the
Lancet review and senior lecturer at the Institute of Neurology, said:
"Alzheimer's disease is the result of very slow degeneration caused by the
death of nerve cells. We probably don't see symptoms until 30 to 40 per
cent of the nerve cells have died. Something regulates this decay and if we
could slow it by even a small fraction we might delay by a decade the point
where someone loses their memory."

But cannabis is a double-edged sword, with potentially damaging side
effects. "It may be possible to develop drugs that allow selective
targeting of different areas of the brain and spinal cord and there may be
a way of limiting the negative effects," Dr Baker said.

A study by Dr Baker and colleagues, in which the natural system of
cannabinoid receptors was removed in mice, showed that the rate of nerve
loss was increased, indicating its role in preserving brain function. The
study, which has been accepted for publication in a medical journal,
"really clinches the argument", Dr Baker said.

He added: "Cannabis has gone from the drawing board into trials in record
time, largely because of patient pressure. Hopefully it will work and be
acceptably safe."