POT STUDY OFFERS SURPRISE

Marijuana researchers have found that a component of pot may intensify
the severity of the most common type of epileptic seizures.

The finding was a surprise for research group leader Dr. Michael
Corcoran at the University of Saskatchewan, who said this week he
expected findings would support older research that had suggested high
doses of THC, the psychoactive ingredient of cannabis, could suppress
grand mal-type seizures.

Now, Corcoran suspects the effects of THC or its synthetic form, known
as cannabinoids, may depend on the part of the brain where the seizure
occurs. The regions of the brain that are susceptible to epilepsy are
mainly those involved in learning and memory, he said.

Corcoran's experiments on rats have shown that seizures which begin in
the temporal lobes appear to last longer and be more severe after
cannibinoids are administered.

He thinks studies conducted in the 1980s, which suggested some
seizures may be suppressed by marijuana, may have been looking at
grand mal seizures that begin in a different part of the brain, the
brain stem.

Research conducted in the past decade has found that there are at
least two, possibly three, different types of receptors in the body
for marijuana-like compounds, including some on nerve cells.

These "cannabinoid receptors" normally are acted upon by various
naturally occurring marijuana-like substances called "endogenous
cannabinoids."

One of those endogenous cannabinoids has been aptly labelled andomide,
a term derived from the Sanskrit word meaning bliss, Corcoran noted.

Identifying and cloning the receptor allowed researchers to design
artificial drugs that act very selectively at that receptor, to turn
it on or block the action of cannabinoids, Corcoran said.

Using a process called kindling, Corcoran gradually induces epilepsy
in rats by administering low doses of electricity to the brain. Once
epilepsy has been induced, the brain becomes more susceptible to
seizures than a normal brain.

Corcoran found that administering cannabinoids before kindling caused
rats to develop epilepsy much sooner than those that didn't get the
marijuana component.

"It's really completely the opposite of what I expected," he said.

"Instead of finding potentially useful anti-epileptic effects, we
found the opposite."

Still, Corcoran is not saying people who smoke pot are more likely to
develop epilepsy.

The true effects won't be known unless clinical trials are done on
humans and those could result in other findings.

A classic example is thalidomide, an anti-morning sickness drug which
had the devastating side-effects of causing congenital deformities of
the limbs in humans, though no such side-effect had shown up in animals.

The results of the older studies were not particularly impressive
because they required such high doses that side-effects resulted,
Corcoran said.

However, the view persisted that marijuana has potential as an
anti-epileptic agent that could be used in therapy. Although research
on the subject died out, some epileptics who cannot tolerate the
normal anticonvulsant drugs use marijuana to control seizures with no
previously identified side-effects.

While Corcoran is not prepared to dismiss the possibility that
marijuana may help control epilepsy, it is also possible users are
experiencing a placebo effect, he said.

"Our species is remarkably adept at kidding ourselves," he said.