Psychiatric Confusion?

dag.stenberg at helsinki.nospam.fi dag.stenberg at helsinki.nospam.fi
Sat Jan 1 09:51:58 EST 2000


In bionet.neuroscience Ian Goddard <Ian at Goddard.net> wrote:
In bionet.neuroscience Ian Goddard <Ian at Goddard.net> wrote:
>   IAN: So what's your point Dag? Someone said without
>   documentation that antidepressants heal the hippocampus.
>   I pointed out that at least two drugs said to have an
>   antidepressant effect suppress hippocampal activity.
>   You respond that maybe that action occurs in other
>   locations of the brain. So what? The hippocampus
>   was the issue raised, so it's what I addressed;
>   why do you now request I address other areas?

Well, in the courese of this discussion I have had to read up a little
on the depression - hippocampal regeneration connection, so I am not any
more as dubious as when this discussion started. It may, of course,
confuse anybody if somebody in this group actually starts to develop
their mind instead of standing on what they posted.

>   IAN: Don't MAOIs increase 5HT in the cleft?
>   A graphic I have from a physiology book shows
>   5HT being metabolized in the synaptic cleft.

Metabolism in the cleft is mainly by the enzyme COMT. I cannot straight
away answer your question whether MAOIs increase synaptic 5-HT. You must
emember that the only reliable way to find out is to take an
experimental animal with implanted microdialysis cannula, administer
MAOI and measure 5HT. Any other "evidence" is indirect and based on
assumptions. It would be easy to check the literature, starting with
PubMed, and going on from there, but I cannot do so just now.
  All textbooks are oversimplified and as to details normally outdated
even when they appear. They can just point one in the interesting
directions. For instance, I did consult a Pharmacology textbook, and
Zigmond's Neuroscience, without getting any wiser. To KNOW, one has to
dig deeper.

>   IAN: I didn't find any studies showing a link
>   to drug-induced hippocampal neurogenesis, and
>   the person who made that claim disappeared
>   when asked to supply supporting documentation.
>   I don't believe that antidepressants have been
>   shown to improve memory, in fact, what I have
>   read would suggest that they impair memory.

Yeah, many things are more complicated than we would like. I am getting
a bit panicky, because there is so much to know, study and find out by
experiment, and I am not getting any younger.

Dag Stenberg




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