From: tong@ohsu.edu (Gong Tong)
Subject: Re: Is MSG sensitivity superstition?
Article-I.D.: ohsu.1993Apr16.194316.25522
Organization: Oregon Health Sciences University
Lines: 48

In article <1993Apr16.155123.447@cunews.carleton.ca> wcsbeau@alfred.carleton.ca (OPIRG) writes:
>In article <1993Apr14.122647.16364@tms390.micro.ti.com> david@tms390.micro.ti.com (David Thomas) writes:
>
>>>In article <13APR199308003715@delphi.gsfc.nasa.gov>, packer@delphi.gsfc.nasa.gov (Charles Packer) writes:
>>>>Is there such a thing as MSG (monosodium glutamate) sensitivity?
>>>>I saw in the NY Times Sunday that scientists have testified before 
>>>>an FDA advisory panel that complaints about MSG sensitivity are
>>>>superstition. Anybody here have experience to the contrary? 
>>>>
>>>>I'm old enough to remember that the issue has come up at least
>>>>a couple of times since the 1960s. Then it was called the
>>>>"Chinese restaurant syndrome" because Chinese cuisine has
>>>>always used it.
>>
>>So far, I've seen about a dozen posts of anecdotal evidence, but
>>no facts.  I suspect there is a strong psychological effect at 
>>work here.  Does anyone have results from a scientific study
>>using double-blind trials?  
>
>Check out #27903, just some 20 posts before your own. Maybe you missed
>it amidst the flurry of responses? Yet again, the use of this
>newsgroup is hampered by people not restricting their posts to matters
>they have substantial knowledge of.
>
>For cites on MSG, look up almost anything by John W. Olney, a
>toxicologist who has studied the effects of MSG on the brain and on
>development.  It is undisputed in the literature that MSG is an
>excitotoxic food additive, and that its major constituent, glutamate
>is essentially the premierie neurotransmitter in the mammalian brain
>(humans included).  Too much in the diet, and the system gets thrown
>off.  Glutamate and aspartate, also an excitotoxin are necessary in
>small amounts, and are freely available in many foods, but the amounts
>added by industry are far above the amounts that would normally be
>encountered in a ny single food.  By eating lots of junk food,
>packaged soups, and diet soft drinks, it is possible to jack your
>blood levels so high, that anyone with a sensitivity to these
>compounds will suffer numerous *real* physi9logical effects. 
>Read Olney's review paper in Prog. Brain Res, 1988, and check *his*
>sources. They are impecable. There is no dispute.
>
>                    --Dianne Murray    wcsbeau@ccs.carleton.ca

In order to excitotoxin effects of MSG, MSG that in blood must go through 
blood-brain barrier that I am not sure MSG can go through or not. In normal condition, the concentration of glutamate in the cerebrospinal fluid is about 
2 uM that is high enough to activate one type of glutamate receptor-the NMDA
receptor. But the question is Neuron and glial cell in the brain have a lots of transport to get glutamate into Neuron or glial. So no one know exact concentration of glutamate is around neurons. 

Glutamate is most important neurotransmitter in the central nervous system. It is involved in not only in daily life like the controling of movement, it is alsoinvolved in develpoment, memory and learn (it is involved in Logn-term potentialtion that be thought is the basis of learning). 
