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F. Frank LeFever flefever at ix.netcom.com
Fri Feb 19 22:09:47 EST 1999

In <36CC94D9.C42A57A4 at sas.upenn.edu> Edward Justin Modestino
<ejmodest at sas.upenn.edu> writes: 
>Bill Gates,
>Oh sorry Dave,
>What do you mean by the abundance of neurotransmitters (NT's)?  Do you
>the availability of NT's?
>     Monoamines are usually abundant among those with average diets. 
>is because average diets contain their amino acid precursors, i.e.
>L-tryptophan, L-tyrosine.

No, he means ABUNDANCE of neurotransmitters, as he said.  That is, the
question is why do we need SO MANY DIFFERENT KINDS of

I think this meaning was quite clear in the rest of his post, even if
you didn't get it on first reading of the phrase.  Why are you so quick
to comment on things you haven't digested or even clearly read?

re his speculation as to reason: there is a grain of truth, in that
there are regions in which one transmitter or another predominates, and
although normally the delivery of specific neurotransmitters are on a
much more fine-grain basis, one can see regional vulnerabilities in
conditions affecting primarily the neurotransmitter(s) especially
important to a given region (cf. PKU and frontal dysfunction?).

In general, though, I would agree with the "fine-tuning" explanation.

re evolutionary garbage: I believe some rather "ancient" species have
an "abundance" of neurotransmitters--but maybe that's the point, i.e.
they haven't evolved in millions of years.  Nonetheless, I wonder if
your instructor can think of some trasmitter she'd be willing to do

F. Frank LeFever, Ph.D.
New York Neuropsychology Group

Prior post continues below:

  Of course, this excludes those with
>neuropathologies.  They may even have abundant NT's but don't respond
>them correctly due to receptor malfunction, lesions, etc.  Other
>may have a deficiency of NT's.  However, other transmitters are not as
>dependent upon dietary precursors.
>    Could you please clarify the question and also what your prof.
>about evolutionary garbage?  Was she suggesting as we have evolved, we
>need less NT's and therefore our abundance is just vestigial like
tonsils or
>an appendix?
>Bill Gates wrote:
>> Howdy,
>>     This group doesn't seem to have much traffic, but it could just
>> my server.  I have a
>> question.  In my neurobiology class, we were discussing the
abundance of
>> neurotransmitters; and my prof asked us for guesses of the cause. 
>> put me on the spot, so I suggested that perhaps certain regions of
>> brain primarily respond to certain transmitters, and other regions
>> more responsive to another subset.  Thus, it would be possible for
>> brain to regulate activity in various regions by simply controlling
>> concentration of various transmitters.
>>     My prof didn't buy this explanation (and I don't entirely blame
>> since I pretty much made it up from my meager knowledge of
>> neurotransmitters), and instead suggested that the abundance is to
>> facilitate "fine tuning" of the transmitter action.  She further
>> suggested that part of the abundance is due to evolutionary
>> I don't entirely buy her explanation.  Would anybody be able to shed
>> some light on this issue?
>> Dave

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