Page 26 - 1

26
injected heroin. When the heroin is removed, that weight is
unbalanced and it begins to produce the constellation of symptoms that
are known as withdrawal symptoms, or "drug sickness."

The symptoms begin with vague uneasiness and irritability. But as the
time from the last dose increases, they include sweating and chills,
nausea and stomach cramps, which progress to nausea, vomiting and
diarrhea; diffuse muscle and joint aches and pains. None of these is
catastrophic by itself, but when the complete syndrome is established
and getting progressively worse, it drives the person to seek relief in
the form of another injection or dose of heroin which will quickly
restore the balance and relieve the symptoms, making them feel more
normal. As the months and years of addiction slide by in the twilight
mental state of addiction, the person obtains less and less of the
positive incentive of the high and more and more of the negative
misery of withdrawal. And so ultimately, it is the brain's defense
against the continuous onslaught that becomes the engine that drives
the dynamics of addiction.

Methadone is effective because, after a single oral dose, it occupies the
opiate receptors and prevents withdrawal symptoms. Further more,
when an adequate dose is established, it prevents the craving for
heroin that fuels the continuing compulsion to seek the drug.

Why Do We Have Opiate Receptors?

This question came up earlier, and it is a very important question. If
evolution has selected for those characteristics that make it possible to
survive on this planet, why would our genetic code provide for the
synthesis of a structure that responds to interaction with a substance
found in one particular plant?

In the early 1970s scientists discovered that there were specific sites in
the brain of mammals that would bind morphine and other opiates that
were labeled with radioactive markers, and that these sites were
located in specific areas of the brain that were involved in the
perception of pain. They began to postulate that these receptors were
actually intended to be interacting with a substance produced by the