I think the l-glutamine issue is one of degree. It is not absolute in stimulating the brain.

What Dr. Blaylock said:
1) MSG is an inorganic rapidly acting substance. Organic glutamates in food (and I would include glutamine) have to be metabolized, so that slows its actions down considerably.
This pathway of glutamate metabolism is an example of how complex it can be:
http://www.genome.jp/kegg-bin/show_pathway?map00471

2) One statistic he did not give but implied, is the fact that glutamate is everywhere in the body. In fact up to 70% of neurotransmission is glutamate based in the brain. What is toxic about it is when cells are damaged/burst in trauma or stroke and glutamate escapes from the cells and destroys tissue around them.

Many foods we eat naturally are high in glutamates. Parmesan cheese is one of the highest. But this is organically bound glutamate unless altered by food processing in some artificial way.

We over at the PN forum avoid MSG all the time. For people with pain, MSG is a trigger for MORE pain.

Thanks for the link to this video. I'll be putting it up at PN here, where we can all use it. I always enjoy Dr. Blaylock MD.