Newsgroups: talk.politics.drugs,alt.drugs
From: [b w hite] at [oucsace.cs.ohiou.edu] (William E. White )
Subject: Re: Drug Myths (Was: Singapore govt. murders dutch engineer)
Date: Sat, 5 Nov 1994 17:08:38 GMT

In article <[1994 Nov 3 175109 26100] at [pixar.com]>,
Little Red Rooster <[n--h] at [pixar.com]> wrote:
>In article <3948ic$[6 o] at [noao.edu]>, Mary Ker <[m v k] at [yogi.tuc.noao.edu]> wrote:
>>In one medical article I was looking at recently they did SPECT
>>studies of the brains of crack cocaine users and found that unlike normal
>>(non-cocaine users) people, the uptake of tracer was very patchy, with
>>distinct focal defects; in plain english, that means that the brain had
>>these big inactive areas.  Does that affect the way people function? 

A bit of introductory knowledge to cocaine's neuropharmacology ...

Although many people compare cocaine in its activity to the amphetamines,
its mode of action is susbstantially different.  Cocaine operates as a
dopamine reuptake inhibitor; that is, it blocks the site where used
dopamine is taken back into cells to be reused or recycled.  (The
amphetamines cause a flood of catecholamines (dopamine and noradrenaline)
to be released from neurons).  Cocaine is also a sigma ligand, and may
operate at the PCP2 site given its binding similarity to sigma.
Now, chronic, high-level use of amphetmines does seem to carry with it
some danger of neurotoxicity, apparently from a toxic metabolite of
dopamine via an enzyme pathway that doesn't become relevant unless
there's a *whole lot* of dopamine around.  However, this toxicity may
be dependent upon the dopamine metabolite being uptaken into the
cell (which cocaine blocks).
In any case, the "big inactive areas" may very well have been the
effect of prolonged reuptake blockage rather than any damage per se.

Oh, and incidentally, I think if you look at alcohol prohibition
you'll notice that, when alcohol was illegal, there was a tendency
towards the use and distribution of the most potent product available.
This trend is occurring today with the use and distribution of cocaine
freebase ("crack").  I doubt crack would exist without the WoSD.

>  Thats right. Most people use between 2 and 10 percent of their brains.

Actually this figure is pretty much bunk.  It may be true that only 2 to
10 percent of neurons are firing at a given time.  This is a good thing.
If, say, 20 or 30 percent were firing at a given time, you'd probably
be in a siezure.  If 100 percent were firing, you'd most likely have
been struck by lightning.

> PS: Anyone care to speculate about the possible purpose of the other
>     90 to 98 percent of the brain? I know, "what does this have to do
>     with t.p.d?" Just curious...

Think of neural nets like photographs or holographs.  If all the pixels
(or silver crystals) were "on" there would be no image.  A much better
indicator of mental performance would be the number of NMDA receptors,
esp. on hippocampal neurons, but that's a fairly new and somewhat
controversial result.  [Keller EA, Borghese CM, et al; Brain Res. 1992;
March 27; 576(1):162-164].


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