Posted by Adam on December 19, 1999, at 22:49:06
In reply to Re: melatonin, posted by Adam on December 19, 1999, at 16:11:29
I don't know what the hell just happened above. Please forget about
all but the last message. Dr. Bob, could you please erase the others?
It looks kind of silly :).> 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
> is essential, and the reaction only goes in one direction. The enzyme can become saturated,
> but it won't start making 5-HT out of N-acetyl-5-HT, so a chemical "equilibrium" does not
> exit per se. However, your intuition could lead one to considering an equilibrium based on
> 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/17160.html