Richard Norman rsnorman at mediaone.net
Tue Jul 25 07:45:14 EST 2000

You are right, theoretically, in your quest for a specific blocking
agent that would inhibit a particular receptor in a particular organ.
IF a particular organ does have a particular receptor subtype
AND IF that subtype is not found elsewhere, then it SHOULD be
possible to influence that particular receptor without side effects.

There are many perhaps insuperable practical problems dealing
with all those hedge words in the proposition.  Receptors are found
to come in a bewildering variety of types with a bewildering distribution
to different sites.  And, as Richard Vickery noted, the distribution can
change over time.  And drugs are not perfectly selective, agonists and
antagonists have different affinities for different receptor types but the
selectivity is not absolute.  And physical ailments result from the
malfunctioning of complex, integrated systems.  Blocking a receptor,
for example, may seem to work but can also produce upregulation so
the system simply produces more and more receptor to restore function.

Virtually all drugs work on a cost-benefit basis.  Nothing is free of
side effects.  The question is whether the benefit outweighs the harm.

But if you ever do find a way of relieving tinnitus, please email me
immediately!  It would be a blessed relief!

"Christian" <cffeld at gmx.de> wrote in message
news:397D4F5F.85A400F7 at gmx.de...
> x-no-archive: yes
> Richard Vickery schrieb:
> > Well, yes there are different NMDA receptor sub-types, and their
> > distribution does vary with developmental age and brain
> > location.  As to what sort of NMDA receptors are present in the
> > cochlea I can't help you.  Why do you want to know?
> Thank you for your reply. To my knowledge, NMDA-receptors-antagonists
> are believed to have a great potential for the treatment of inner ear
> diseases such as tinnitus. However, as it seems, the danger of
> side-effects limit their use. I'm therefore interested if it would
> theoretically be possible to develop NMDA-receptor-antagonists which
> only work in the cochlea - it's just an idea that came up in my mind
> and I'm not sure if there is any realistic chance that it could work
> some day.
> Regards,
> Christian

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