From: wcsbeau@alfred.carleton.ca (OPIRG)
Subject: Re: Is MSG sensitivity superstition?
Organization: Carleton University, Ottawa, Canada
Lines: 44

In article <1993Apr16.194316.25522@ohsu.edu> tong@ohsu.edu (Gong Tong) writes:
>In article <1993Apr16.155123.447@cunews.carleton.ca> wcsbeau@alfred.carleton.ca (OPIRG) writes:
>>
>>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.

Elevated levels of Glu and Asp in the blood are able to bypass the
Blood-brain barrier through the circumventricular organs (or CVO), in
particular the adeno and neurohypophysis (pituitary gland) areas.  The
arcuate nucleus of the hypothalamus, and the median eminence regions
are particularly effected.  CVO areas are not subject to the
blood-brain barrier. These areas control the release of gonadotropin,
which controls the release and flux of steroids governing development,
especially sexual development. Changes in adult rats, which are less
sensitive to Glu than humans, have been observed: after ingesting Glu,
on a chronic basis, cycles of several steroids are disrupted. Blood
levels of somatostatin are significantly reduced, and cyclic release
of steroids becomes flattened.

                    Hope this helps.
                    --Dianne Murray: wcsbeau@ccs.carleton.ca



