'SMOKE TWO JOINTS' MAY BE BAD ADVICE

EFFECTS: Marijuana Can Pose Dangerous Physical Risks, Some Scientists
Say

Some marijuana enthusiasts may be in the dark as to how those "blunts"
produce a high and other associated effects.

Over the years, researchers have found that marijuana produces both
harmful and beneficial effects in the body.

"Tetrahydrocannabinol is one of 60 compounds in marijuana smoke that
have a similar chemical structure, called cannabinoids, but it is
responsible for the high," said UCLA Professor of Medicine Donald
Tashkin.

After inhaling marijuana, the smoke is absorbed in the lungs, where it
fills up capillary beds. It is carried by the circulatory system into
the brain, where most of its effects occur, according to psychology
professor Carlos Grijalva.

A burning joint is made up of two components, the particulate and the
gas phases, both of which can be potentially harmful.

THC is concentrated in the particulate phase, or the tar, where it is
deposited in the lung or absorbed in the blood stream.

The gas phase is an irritant and contains cyanide and formaldehyde.

"Despite common belief, marijuana is much more toxic than cigarettes,"
said Professor of Medicine Michael Roth. "The toxic effects are probably
cumulative, meaning the more you are exposed, the more risk you face."

But smoking one to two joints a day can do as much damage as smoking one
to two packs of cigarettes, Roth said.

Because marijuana joints have no filter and users inhale it so deeply,
much more of the carcinogens are deposited in the lung.

Marijuana is 10 to 20 times more potent than cigarettes in terms of
toxicity and carcinogenic properties, not including the immunological
effects unique to marijuana, Roth said.

But according to scientists, the human body produces endo-cannabinoids,
compounds similar to THC.

"We produce endo-cannabinoids called anandamides, which are structurally
different from THC, Tashkin said. "The name comes from the Sanskrit word
meaning 'bliss.'"

Tashkin said ways to increase levels of natural anandamides will be a
major area of research in the future.

Cannabinoids must bind to special proteins found on cell membranes to
function properly.

"Cannabinoids bind to specific receptors, CB1 receptors located in the
brain, and CB2 receptors located in other parts of the body," Roth said.

THC acts as a key as it attaches to receptors. The protein changes shape
when the compound binds, triggering a chain of chemical events.

For example, if it binds in the basal ganglia, a part of the brain, it
could affect movement and coordination, Tashkin said.

The receptors are most highly concentrated in parts of the brain that
process memory, regulate emotions and coordinate movement.

"(THC) has its major effects on the central nervous system and acts as a
mild sedative, resulting in a sense of tranquility and euphoria for
individuals used to it," Tashkin said.

But those who are not used to its effects often experience anxiety or
panic, he said.

Scientists at UCLA are making advances to further explore the negative
aspects of the compound. According to researchers, THC can also bind to
CB2 receptors on white blood cells leading to malfunctions in the body's
defense system.

Mice vaccinated for certain diseases have been shown to lose their
immunity to illnesses while they are on THC, and similar effects have
been with human cell cultures.

"These cells are not able to fight off infections," Roth said.
"Specifically, marijuana smokers are at an increased risk for
infection."