Doctor Specializes in Pot Research

              Concentrates on Physical Effects
Doctor Specializes in Pot Research
By Elaine King
Times Medical Writer
If you smoke a joint of marijuana and
don't get high, don't be fooled into
thinking that marijuana doesn't bother
you.
It does.
Your pulse rate will speed up and your
eyes will get bloodshot, even if you don't
feel the much talked about high attributed
to smoking marijuana.
Those are things that a marijuana
smoker can tell for himself. But there are
also some less obvious physical effects
that scientists have recently discovered.
Dr. Joseph Manno of Shreveport
outlined some of the things he has learned
about marijuana's effects on users' bodies
in his extensive research.
He and his wife, Dr. Barbara Manno,
have continued researching marijuana
and its effects on the body for several
years. Both are associate professors of
pharmacology and therapeutics at
Louisiana State University School of
Medicine in Shreveport and she is a phar-macologist
in medical research at the
Veterans Administration.
For instance, he explained, by injec-ting
THC (the ingredient in marijuana
analogous to alcohol in liquor) into an
isolated heart, the Mannos discovered
that the blood vessels to the heart con-stricted
and the heart beat with substan-tially
less force than before.
The amount of THC (tetrahydrocan-nibinol)
used in the experiment was close
to the amount found in the blood after
smoking marijuana. In other tests that
amount was increased to simulate the
higher concentrations of THC in the blood
of regular users since THC accumulates
in the blood stream, he explained.
In a healthy person, those effects
probably wouldn't cause any physical
problems, Dr. Manno said.
Could Be Dangerous
But for anyone whose "heart is not a
completely efficient pump" it could be
dangerous, he said.
Research with animals to determine
effects of marijuana on the heart, was
corroborated, Dr. Manno noted, by fin-dings
of a California researcher who used
I heart patients in research.
In the California research, conducted
under controlled conditions, the heart
I patients would begin exercising and con-tinue
until their chest pains began.
If it took five minutes for the pains to
begin after exercise started, it would take
only half as long for the pain to develop
[after the person smoked marijuana,
according to Dr. Manno.
In Shreveport none of the marijuana
research has included people, which made
corroboration of some of the Mannos
other findings difficult, he said.
"You can't pull people off the streets"
for research tests, he commented.
But now, coupling his own results with
the'findings from the California research,
Dr. Manno can caution that if a
marijuana smoker, who suddenly stands
up after being seated or reclined, faints it
is no coincidence.
And it's no coincidence if after
smoking marijuana chest pains begin. It's
likely a heart problem aggravated by the
marijuana's effects, he said.
The Mannos are among a group of
about half a dozen scientists in the United
States whose marijuana research concen-trates
on the physical effects.
Most of the researchers have delved
i n s t e a d into the psychological
implications of smoking marijuana, he
said.
Smoker May Faint
One of the reasons that a marijuana
smoker may faint or get weak if he stands
after smoking is because the blood vessels
don't constrict as they normally do to
keep gravity from pulling the blood down-ward
when a person stands, Dr. Manno
theorized.
If that's true, then marijuana also has
a dilating effect on areas other than the
eyes, in direct contrast to the constriction
of the heart blood vessels, he said.
That could be caused by different
effects along the central nervous system
or it could affect parts of the body differen-tly.
"Why I have no idea," he readily
admits. That's what the on-going research
is all about. To find out the unknown about
what marijuana does to the body, and
why.
The latest research underway will take
months to conduct and is aimed at finding
out if marijuana affects the central ner-vous
system directly.
Working with Dr. Manno on the
project, which involves rats, is Elizabeth
Loftus, who is working on her Ph.D.
In the past, the Mannos' research with
animals has yielded important results
that corroborated theories about
marijuana and its physical effects.
For instance in early research the
Mannos were able to prove the in-creased
pulse rate by giving animals THC
in small doses that equal the blood level
amount.
Previous researchers had found a
decreased pulse rate in animals injected
with THC. But those results came when
high doses were injected into anethesized
animals, Dr. Manno said.
The Mannos work proved the in-creased
heart rate was caused by THC.
Research is centering on THC
metabolites, the altered form of THC
after it is processed through the body.
If THC is admijustered into test
animals, Dr. Manno noted, it takes about
90 minutes for the increased pulse rate to
begin. But if a metabolite is injected, the
heart rate picks up immediately, he said.
The Manno research into what
marijuana can do physically to a smoker
is still continuing in an effort to find out
more about the controversial drug.
Where is the research leading?
Eventually, said Dr. Manno, he would
like to work with coroner cases to
establish how often THC is found in the
bloodstream of persons involved in
automobile fatalities.
That's much the same way that alcohol
was finally pinpointed as a major factor
in wrecks, he noted.
Checking out some of the equipment used to test marijuana's effects on
rats ris. Dr. Joseph Manno, who has been conducting research on the
physical effects of marijuana. (Times Photo by John Denison)