THE LOWDOWN ON POT AND BOOZE

An Overview Of Some Recent Studies

The fourth week of classes are upon us and many first year students, having
already attended ample parties, are beginning to come to terms with their
new geographical position: a safe distance from the watchful eye of the
parental unit. This may account for the popular perception of a "frosh" as
a half crazed, over-sexed young person that tends to make too much noise
and consume exorbitant amounts of alcohol and marijuana. So, in the service
of these freedom-drunk Mount Allison students, who should be a little bit
curious as to what's going on inside their body every weekend, and in the
wake of Canada's decriminalization debate, here is a brief overview of some
recent studies concerning alcohol and (ever more controversial) marijuana.

Marijuana

Marijuana is the common name for Cannabis sativa, a hemp plant that grows
throughout temperate and tropical climates. It consists of over 66
different organic substances called cannabinoids. Tetrahydrocannabinol
(THC) is the primary psychoactive ingredient but other cannabinoids have
some effect when combined with THC.

Neurons in the brain are activated when a compound binds to its receptor,
which is a protein typically located on the cell surface. All recent
studies have indicated that the behavioral effects of THC are receptor
mediated so THC will exert its effects only after binding to its receptor.
In general, a given receptor will accept only particular classes of
compounds. Components of different drugs bind to different receptors in the
brain, THC binding to the receptor that is most abundant (10 times more
abundant then the receptors responsible for the effects of morphine).
Binding to a receptor triggers an event or a series of events in the cell
that results in a change in the cell's activity, its gene regulation, or
the signals that it sends to neighboring cells. Given that these receptors
exist, there must be another substance, similar to cannabinoids, within the
body. Indeed researchers have found a few, though their physiological use
is not yet known. The normal biology and behavior associated the areas
where the cannabinoid receptors are most abundant are consistent with the
behavioral effects produced by cannabinoids (for example the hippocampus,
the area responsible for learning, memory and stress have an abundance of
receptors).

Some Effects:

- -Short term memory is disrupted. This is consistent with the abundance of
cannabinoid receptors in the hippocampus, the brain region most closely
associated with memory.

- -Acute reactivity to pain is reduced. This is why a recent study has showed
that relief of pain is the most common use of medical marijuana.

- -After repeated use, a tolerance to the effects is developed. Most studies
show that concentrations of cannabinoid receptors decrease with long term
exposure to marijuana (although a minority of studies suggest otherwise).

- -THC can modulate the function of immune cells in various ways - in some
cases enhancing and in others diminishing the immune response depending on
a slew of factors.

- -Animal research has demonstrated the potential for dependence, but this
potential is observed under a narrower range of conditions than with
opiates, cocaine, or nicotine and withdrawal symptoms have been observed
but to a more mild degree then drugs such as alcohol.

Alcohol

If the simple single celled organism, yeast, feeds on simple sugars in the
absence of oxygen it releases two waste products: carbon dioxide and ethyl
alcohol. The various forms that alcohol reaches the consumer in are
developed by various ways of controlling the fermentation process. When
consumed, alcohol bypasses most digestive processes and enters the blood
stream directly. This is because ethyl alcohol is completely miscible in
water (its -OH member forms a hydrogen bond with the water molecule making
ethyl alcohol "hydrophillic," water attracting), thus it is readily
distributed throughout the body in the aqueous blood stream after consumption.

Although, when consumed orally, alcohol can be absorbed at any point on
route from the mouth down the esophagus and into the stomach, the majority
is absorbed from the stomach and the small intestine. A number of factors
effect the absorption rate of alcohol into the blood stream such as the
presence of food and exercise, which both reduce the rate of "gastric
emptying." Since alcohol mixes with water, its distribution in the blood
(80% water) parallels that of the water content in blood. The more one
drinks the higher the concentration of alcohol becomes in the blood. More
than 90% of the ethyl alcohol that enters the body is completely oxidized
to acetic acid. This process occurs primarily in the liver. The remainder
of the alcohol is not metabolized and is excreted either in the sweat,
urine, or given off in one's breath.

Some Effects:

- -Because of alcohol's water solubility, it readily crosses important
biological membranes, such as the blood brain barrier, to affect a large
number of organs and biological processes in the body.

- -It lowers inhibition: it inhibits cells and circuits in the brain which
themselves are normally inhibitory. This effect is the reason why people
tend to be more outgoing when drunk.

- -When the liver metabolizes alcohol toxic substances such as acetaldehyde
and the highly reactive molecules called free radicals are created.

- -Many of the processes used by the kidneys to regulate the volume and
composition of fluid and electrolytes in the body are damaged.

- -Ethanol consumption can be both beneficial and harmful to the
cardiovascular system. This is effected dramatically by quantity and
frequency of alcohol ingestion and by many other factors related to
specific physiology. Moderate drinking may reduce plaque deposits in the
arteries (atherosclerosis), protect against blood clot formation (protects
against heart attack and stroke), promote blood clot dissolution (protects
against heart attack and stroke). Heavy drinking can lead to increased risk
for heart muscle disease (cardiomyopathy), increased risk for disturbed
heart rhythm, increased risk for high blood pressure and increased risk for
hemorrhagic stroke.

(Info for marijuana came mostly from a 1999 study by the Academy of
Science, Institute of Medicine: "Marijuana and Medicine."
http://www.nap.edu/html/marimed/. For alcohol: chemcases.com
http://chemcases.com/alcohol/ and a Virginia Tech study at
http://www.alcohol.vt.edu/Students/alcoholEffects/brainBody.htm)