Excitotoxins: The Taste That Kills by Blaylock Russell L

Author:Blaylock, Russell L. [Blaylock, Russell L.]
Language: eng
Format: mobi
ISBN: 9780929173252
Publisher: Health Press NA Inc.
Published: 1996-11-30T16:00:00+00:00

Another interesting discovery is that as our nervous system ages our neurons (NMDA type glutamate neurons) have more difficulty controlling the influx of calcium into the cel1.[338] This would mean that as we age our brain would become more vulnerable to excitotoxin damage. This is why the older we get the more cautious we should become about eating foods containing excitotoxins such as MSG and aspartate (NutraSweet®).

ENERGY: THE KEY TO BRAIN PROTECTION

In review, we now know that glutamate, if given in large doses, can kill neurons containing glutamate receptors. For this reason the brain must have some mechanism to protect itself from high concentrations of glutamate in the blood. It does this by the blood-brain barrier. Previously, it was thought that when this barrier system was working properly it could protect the brain from even massive concentrations of glutamate and aspartate in the blood. To some extent this is true.

The brain normally contains relatively low concentrations of glutamate and aspartate, which are used as metabolic fuels and as neurotransmitters. (Glutamate is the most common neurotransmitter in the brain.) But the concentration of these excitatory amino acids within the brain must be carefully regulated so as to prevent toxic amounts from building up around the neurons. To prevent this from happening, the brain possesses an elaborate system to prevent glutamate accumulation. It does this by using an energy dependent pump system that literally pumps excess glutamate found in the fluid circulating around the neuron into surrounding glia cells. Once in the glia cell the glutamate is deactivated by special enzymes. By carefully controlling the amount of glutamate near the neuron’s glutamate receptor, the protective pumps prevent excess stimulation of the neuron. It works sort of like a thermostat in a tropical fish tank. If the water gets too cold or too hot, the fish will die. The thermostat keeps the amount of heat just right. But the thermostat in the fish tank requires electricity to operate. If the power fails, the thermostat also fails and the fish die. The energy driven pumps in the glia do the same thing; they keep the concentration of glutamate at just the right level, so that the neurons won’t die.

If this protective system fails because of a lack of energy, glutamate will began to accumulate and stimulate the receptors on the surface of the cell membrane allowing calcium to pour into the cell. As a result the neuron will become overexcited. Also, excess calcium triggers a cascade of destructive reactions that can lead to cell death. Normally this protective mechanism is very efficient in keeping this from happening, but it requires large amounts of energy to operate efficiently. Fortunately, the neuron has a back-up or “fail safe” system should excess calcium enter the neuron. Once excess calcium is detected within the neuron, it will begin to pump this excess calcium back out of the cell. Normally this is a very efficient process, but it too requires large amounts of cellular energy for its operation.

So what

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