On Sun, 11 Jan 2004 20:40:42 +0000 (UTC), erik{at}zoneedit.com (Erik
Aronesty) wrote:

>I was listening to NPR some time ago and they had a parasite expert on
>the air.  He was talking about Toxoplasma gondii.  Toxoplasma gondii
>lives in cats, but the way it spreads is via rats.  When it infects
>the rat, the rat becomes less risk averse, it becomes attracted to the
>smell of cats, and it has a slower reaction time.  In humans, the
>Toxoplasma has a similar effect.  In fact, people infected by it are
>more likely to own cats!
>
>There's one parasite (Euhaplorchis californiensis) that reproduces in
>birds.  This bloodfluke first infects snails that eat the birds'
>droppings.  Then they travel through the water to fish, which they
>infect by swimming into the gills, finding a blood vessel, and then a
>nerve, ending up on the surface of the brain.  The fish then becomes
>more likely to jump out of the water or splash near the surface, which
>makes them about 30 times more likely to be eaten by birds, thus
>completing the fluke's life cycle.
>
>Parasites have evolved over time to control the minds of their hosts. 
>They get their hosts to engage in behavior that promotes their
>existence.
>
>This got me thinking about the various recreational drugs that we find
>in nature.  Might it be that these blood-brain barrier crossing drugs
>similarly evolved to the benefit of their parent species?
>
>Is it possible that the effects of psilocybin on animals actually
>helps promote the survival of the mushrooms that produce it?  How
>about the effects of cannabis or cocaine?
>
>Cows and sheep fall into behavior patterns and rarely migrate outside
>their territory unless given an environmental nudge.  Psychoactive
>mushrooms grow in cow and sheep feces.  They cannot survive without
>animals.  They spread via animal locomotion.  An cow can run from a
>fire.  A mushroom can not.  Their vested interest, for millions of
>years, was for animals to not fall into predictable patterns, and to,
>instead, range far and wide.
>
>Indeed, mushrooms may cause animals to break their established
>patterns of behavior and go to new fields in order to ensure their own
>spread and survival, since they have no locomotive ability on their
>own.
>
>More generally, many plants and mushrooms have hallucinogenic effects
>on animals.  Animal brain receptors and these compounds have certainly
>co-evolved. Indeed, there's a rather specialized "cannaboid receptor"
>in our brain.  Perhaps these are intended to produce behaviors that
>promote the survival of the psychoactive species?
>
>Bob Ross in the "The Joy of Painting", was known to say
"Think like a
>tree".  Perhaps he meant that... literally.

You are correct. The psychoactive drugs, like all secondary plant
compounds, are presumed to be protective and help prevent herbivores
from grazing on that plant.  The basic mechanism is twofold -- at
small concentrations, they are generally supposed to taste "bad".
Then, at larger concentrations, they poison the herbivore.  The first
(bad taste) is really a secondary adaptation of the herbivore to avoid
being poisoned.

Humans are weird creatures.  We have found ways to extract the active
chemical in hot water or by burning the plant and inhaling the smoke.
We flavor the product to minimize the taste problem.  And we figure
out how to control the dose so it is just sub-lethal. Consider the gin
and tonic.  Quinine, the classic example of a bitter substance, is
made somewhat more palatable by the addition of lime and sugar.  Add a
hefty dose of gin and you can forget that it really is supposed to be
a medicine to help protect you from malaria!

The cannabinoid receptor did not evolve to let us react to cannabis.
Rather, the plant developed a chemical that was able to bind to the
receptor that normally responds to an endogenous chemical agent. The
receptors were named after this artificial agonist only because the
real active agent, anandamide, was discovered much later.  The same
thing happened with the opiate receptors.
---
þ RIMEGate(tm)/RGXPost V1.14 at BBSWORLD * Info{at}bbsworld.com

---
 * RIMEGate(tm)V10.2áÿ* RelayNet(tm) NNTP Gateway * MoonDog BBS
 * RgateImp.MoonDog.BBS at 1/12/04 3:12:51 PM