HUMAN BODY MAKES OWN VERSION OF CHEMICALS FOUND IN MARIJUANA

KNIGHTRIDDER NEWS SERVICE

WASHINGTON -- Amid this year's clamorous battles to legalize medical
marijuana stands this little-known fact: Our brains and bodies are flooded
with a natural form of the drug.

Called cannabinoids, after the euphoria-inducing plant Cannabis sativa, this
family of compounds blocks pain, erases memories and triggers hunger. Newer
studies show they also may regulate the immune system, enhance reproduction
and protect the brain from stroke and trauma damage.

Discovered in humans just a few years ago and, until recently, virtually
unstudied, the compounds have become one of the looming mysteries of the
nervous system -- and a field of exploding scientific interest.

Already, scientists are testing cannabinoids with hopes of harnessing the
medical power of marijuana to treat pain without its high, smoke or
political baggage. A key challenge is separating the curing power of the
compounds from their mind-altering side effects.

``That's the Holy Grail of this field,'' said Steven Childers, a
pharmacologist at the Wake Forest University School of Medicine in
Winston-Salem, N.C.

Because cannabinoids are so numerous in the brain, they also could help
explain the workings of some of our body's most complex, and least
understood, systems.

The scientists who discovered the cannabinoids in the brain called the
substance anandamide, Sanskrit for eternal bliss.

Our brains contain receptors that interact with the anandamide we produce.
In an accident of nature and chemistry, compounds in pot are shaped
similarly and therefore trigger similar but more potent effects. The same is
true of the plant drugs nicotine and cocaine.

Now, scientists are beginning to understand just what natural cannabinoids
might be doing in the human body.

``We're opening doors now we couldn't even have predicted existed,'' said
Childers, president of the International Cannabinoid Research Society.

For example:

- -- This week Herbert Schuel and Lani Burkman of the University of Buffalo in
New York reported that cannabinoids help control the exquisite synchrony of
timing during reproduction by slowing overeager sperm if they try to
approach an egg before it's ready for fertilization. This may also explain
why heavy pot users, both men and women, are sometimes infertile.

- -- Cannabinoids have been found to suppress and enhance the body's defenses
against diseases and tumors, a duality that has researchers puzzled. ``It's
a science clearly in flux,'' said Thomas Klein, an immunologist at the
University of South Florida. ``The more we learn, the more confused we
are.''

- -- While pot warnings -- ``This is your brain on drugs'' -- have long
spotlighted the drug's damaging effects on the brain, research last summer
from the National Institute of Mental Health shows cannabinoids protect
brain cells from stroke or trauma damage.

- -- Last year, scientists at the Neurosciences Institute in San Diego showed
that cannabinoids block the formation of new memories in slices of animal
brain tissues. This power to forget might keep brain from filling up or
getting overwhelmed with unimportant memories.

Cannabinoid research in animals already has scientists considering drugs
that might be quite powerful in exploiting an untapped chemical system
within the brain to solve an array of medical problems.

``While no one wants a drug that disrupts memory, maybe you could boost
memory by blocking cannabinoids,'' said Billy Martin, a professor of
pharmacology at the Medical College of Virginia and one of a handful of
people who have studied cannabinoids since the 1970s. Blocking the effects
of cannabinoids might also be a route to a weight-loss drug. ``If marijuana
gives you the munchies, maybe blocking cannabinoids will be helpful in
treating obesity,'' he said. ``It's hard to say what's ahead.''

Researchers' largest hopes are focused on using a synthetic form of
cannabinoids to block pain, including chronic nerve pain that can't be
adequately blocked with existing drugs.

Animal studies show cannabinoids can block other kinds of pain almost before
they begin -- stopping the pain signals before they reach the spinal cord or
brain, working as well as morphine. That power suggests they could be
substituted for morphine, which is addictive and must be used in increasing
doses over time.

Cannabinoids enhance morphine's power; combining the drugs could vastly
reduce the dosages needed to kill pain, offsetting problems of addiction and
drug tolerance. Cannabinoids also counteract nausea, another plus for
patients with cancer and AIDS.

``It might be possible to manipulate levels of the body's own cannabinoids.
You could create drugs like Prozac that block the body's reuptake of
cannabinoids or inhibit their breakdown so they stay active longer,'' said
Andrea Hohmann, who previously worked with Walker and now researches pain at
the National Institute of Dental and Craniofacial Research.

``These kind of manipulations may not have the unwanted side effects of
marijuana and aren't going to carry the same kind of political baggage.''

Medicinal marijuana has its supporters -- including voters in Alaska,
Arizona, Nevada and Washington state who said in referendums this fall that
they favored that use for the drug. But many physicians argue that proof of
marijuana's beneficial effects is hazy and that pot smoke, more toxic than
cigarette smoke, is too great a health hazard.

Use of pot is favored by some doctors for treatment of pain and wasting from
cancer and AIDS. It also has been recommended to reduce the damaging effects
of high fluid pressure within the eye.

But a study in the Archives of Opthalmalogy last month calculated that a
glaucoma sufferer would have to smoke about 3,000 joints each year to bring
the pressure down. And it's unknown which of the plant's many chemicals are
helping.

Checked-by: Rolf Ernst