Posted by Adam on December 19, 1999, at 16:05:27
In reply to melatonin, posted by Elizabeth on December 19, 1999, at 14:58:47
OK, stretching memory banks to the max here...
I don't think Le Chantelier's principle is applicable here because of the nature, if
any, if an "equilibrium" between 5-HT and melatonin production. If you consider the
rate limiting step (N-acetylation of 5-HT by seratonin acetyltransferase), the enzyme
can only drive the reaction in one direction. I can become saturated, but it won't
start making 5-HT our of N-acetyl-5-HT, so a chemical equilibrium does not exit per se
(wrong kind of catalyst). However, your intuition could lead one to considering
more complex feedback loops. Seratonin syndrome would thus depend on at least a
couple of things: There is a periodicity of serotonin production (probably timed with
the synthesis of melatonin), that administration of exogenous melotonin leads to
negative feedback on the melatonin synthesis pathway, and the rusultant surplus of
serotonin is large enough to be harmful.Not a bad theory, I guess.
> > Despite the inkling there could be risks, and your apparent confirmation of this, I can't think of a
> > concrete reason, mechanistically, why this should happen. Do you have any theories. Does melatonin
> > have sympathomimetic properties? Is it recycled into 5-HT? Is it a 5-HT receptor agonist?
>
> I dunno if this applies, but what about le Chatelier's principle?
poster:Adam
thread:16735
URL: http://www.dr-bob.org/babble/19991212/msgs/17138.html