The neurotransmittors Glutamate and Aspartate (in Aspartame) are normally found in the spinal cord and brain. They are two of the most common transmitter chemicals in the spinal cord and brain, but when their concentrations rise above a critical threshold they can turn into deadly toxins to the neurons and nerve cells that are connected to these neurons. Too much Glutamate will not only kill the neurons but it will also kill any neurons that are connected to it. Both Glutamate and Aspartame can cause neurons to become extremely excited and, if given in large enough doses can cause these cells to degenerate and die. The nervous system carefully controls the concentration of these two amino acids in the fluid surrounding the neurons. It has a system designed to remove any excess glutamate from this extracellular space. It is accomplished by a special pumping system that transfers the excess glutamate back into surrounding glial cells. The glial cells surround the neurons and supply them with energy. This pump acts like a bilge pump on a ship, if the pump fails the ship fills up with water and sinks. Normally, the glutamate clearing system is very efficient. While this pumping system is very effective, it requires an enormous amount of cellular energy in the form of ATP (adenosine triphosphate). It works like an old-time fire brigade where a line of people hoist buckets down a human chain to put out a fire. It requires a lot of energy on the the people that make up the bucket brigade. If they ran out of energy the fire would rage out of control. The same thing happens when energy production is reduced in the brain, the protective pumps begin to fail and glutamate begins to accumulate in the space around the neuron, including in the area of the synapse. If the energy is not restored, the neurons will burn up, they are literally excited to death.
Within 15-30 minutes after exposure to high doses of MSG, the neurons suspended in tissue culture are seen to swell up like balloons. You can see the degeneration of the small structures within the cell under the microscope, called organelles. You will also see clumping of the chromatin of the nucleus. Within 3 hours these neurons are not only dead, but the body’s defense mechanisms begin to haul away the debris. The degenerative reaction is seen under experimental conditions using animals when the MSG is either ingested via the diet, injected in the abdominal cavity or applied directly to the neurons in tissue culture into the brain via the cannula or tube.
Glutamate and Aspartate appear to work by opening calcium channels on certain subtypes of receptors. When these neurotransmitters are allowed to come into contact with the receptor in too high of a concentration or for too long a period of time, the calcium channel gets stuck in the open position, allowing calcium to pour into the cell in large amounts. When this happens the protective mechanisms are triggered. But as with the glutamate pumps, the calcium pumps also require large amounts of energy as ATP. This energy must be supplied continuously, especially if the calcium continues to enter in large amounts and for a prolonged period of time. Again, it’s like bailing out a boat that has a large hole in the bottom. To keep from sinking you must bail the water out faster than it flows into the boat. If you have ever been in this position you’ll know that it takes a lot of energy to do this.
So how does calcium actually kill the cell? This is an area of intense research and interest because these calcium channels appear to play an important part in a multitude of seemingly unrelated diseases, such as strokes, heart attacks, arthritis, brain injury, migraine headaches and cancer.
In a nutshell: MSG enters the brain past the blood-brain barrier, triggers neurons to open their calcium channel, the glutamate causes the cell to remain stuck in the open position then calcium floods into the cell in large amounts. This triggers the cell to react in emergency mode and starts it’s special pump that will start pumping out the excess calcium using up large amounts of energy (ATP), the cell swells up with excess calcium and eventually the cell is depleted of energy and dies within two hours. The pump couldn’t pump out the excess calcium fast enough. (It’s like trying to bail water out of a boat with a large hole in the bottom. You use up a ton of energy and eventually the boat is filled and sinks). The cell shrivels up and the body’s defense mechanism sweeps away the dead cell debris.
Excerpts from: Excitoxins: The Taste that Kills. Russell Blaylock M.D.