The Role of Excitotoxins by Amy Yasko good article

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http://www.autismanswer.com/articles/yasko/role_of_excitotoxins.html

The Role of Excitotoxins in Autistic Type Behavior

Dr. Amy A. Yasko

Introduction

I have been researching and working with inflammatory pathways in

the body since my doctoral work at Albany Medical College. I have

always felt that it is critical to understand why something is

happening in order to make informed choices directed at correcting

the imbalance. I believe very strongly that the pathway of

excitotoxin damage as described brilliantly by Dr. Blaylock,

definitely leads to neurological inflammation. In applying the

knowledge of this process to my work with individuals who have ALS,

Parkinson's, MS and Alzheimer's, I have had considerable success in

reversing symptoms of these diseases.

More recently, I have used and extended the concepts of excitotoxin

damage as they pertain to autism. I have found that by understanding

the process that leads to the type of neurological inflammation that

we know as " autism " , I am able to make significant strides in

helping these children. The following represents what I believe is

occurring thus far with respect to the process of neurological

inflammation that results in autistic like behavior. It is a work in

progress, and does not answer every question with regard to autistic

type neurological inflammation. It does however, provide an

explanation for many of the observed behaviors and symptoms that are

associated with autism, a framework from which to help reverse many

of these traits, and a rationale for why many of the currently

utilized therapies are effective.

Although I have never met, nor corresponded with Dr.

Blaylock, I thank him for his explanation and description of

excitotoxin damage. It is from using, and extending his insights

that I have been able to successfully touch and change many lives

that have been afflicted with neurological inflammation.

Overview

Through her consulting practice, Dr. Amy Arrow Yasko has worked with

a large number of individuals with neurological inflammation. This

includes individuals with ALS, MS, Parkinson's Disease, Alzheimer's

Disease, and autism.

Dr. Amy has found that the program she has implemented to

successfully break the cycle of neurological inflammation with other

types of neurological disorders is useful in helping to reverse the

neurological inflammation that manifests as autism. In addition, she

has had success in reversing symptoms of Crohn's disease, which has

been postulated to occur via chronic measles infection as is often

seen with autism.

Dr. Amy views autism as a subset of neurological inflammation, and

as such has applied a variation of the approach that she has

utilized with these other inflammatory disorders to the type of

neurological inflammation that results in autistic like behavior.

While autism has a variety of similarities to other forms of

neurological inflammation (Parkinson's, ALS, MS, and Alzheimer's),

it also has unique features that contribute to the autistic type of

inflammation.

Basically, Dr. Amy approaches neurological inflammation in general

with a three-step program which can be implemented simultaneously.

First, it is critical to remove excitotoxin triggers from the

system. This involves closely monitoring food and supplement intake

to avoid excitotoxins. Excitotoxins are neurotransmitters such as

glutamate or aspartate that can excite the nerves to death when

their levels are not regulated properly. Excess excitotoxins cause

an imbalance in the flow of calcium, which leads to activation of a

complex inflammatory cascade, release of inflammatory mediators, and

ultimately causes the death of neurons. Foods or supplements that

contain excitotoxins include MSG (monosodium glutamate), glutamic

acid, glutamine, nutrasweet, aspartate, aspartame, and cysteine.

Mercury and aluminum can also serve to trigger glutamate release.

Next, it is important to stop the inflammatory process created by

the excitotxin triggers. This is achieved with a number of

supplements known to mitigate inflammatory mediators.

Finally, the third stage is to repair the damage, generate new

neurons, and support the liver. This is accomplished with a number

of supplements, which serve as antioxidants as well as to help

increase glutathione levels, restore liver function, promote nerve

growth, restore vitamin K levels, decrease glutamate levels, and

balance GABA levels.

Dr. Amy has found that in working with autistic neurological

inflammation in particular, there are additional factors to

consider. These include dealing with potentially chronic viral,

bacterial, and yeast infections in the body (which can generate

release of additional inflammatory mediators), balancing the

acid/alkaline ratio and restoring normal flora to the GI tract, and

metal toxicity (which also generates excitotoxin damage).

There are several underlying factors that may predispose certain

individuals to autistic type neurological inflammation. These

include persons of blood type O, (and to a lesser extent blood type

A), early recurrent streptococcal infections, excess stomach acid,

predominantly male sex, early multiple vaccinations, and well above

normal intelligence. There may also be a correlation with a familial

history of liver dysfunction/disease, vitamin K deficiency, acid

reflux, and autoimmune problems.

Excitotoxins

Glutamate is the main excitatory neurotransmitter in the body. It is

essential for learning, and for both short-term and long-term

memory. It is also the precursor to the inhibitory neurotransmitter,

GABA. GABA is a calming neurotransmitter, and is essential for

speech.

Problems occur if the normal process of regulation of glutamate

malfunctions and if toxic levels of this excitatory neurotransmitter

build up in the synaptic junctions. The brain requires sufficient

levels of oxygen and energy to remove excess glutamate. However,

glutamate release leads to the release of insulin, which results in

decreased glucose levels. The amount of glucose in the brain

regulates the removal of excess glutamate from the synapses.

Therefore, a drop in blood glucose disrupts this removal process and

allows the build up of toxic glutamate. In fact, conditions of

hypoglycemia, or low calorie/starvation conditions induce the

release of glutamate and reduce the ability to remove excess levels

of glutamate from the brain. This excess glutamate depletes

glutathione. Glutathione is one of the most powerful antioxidants

found in the body and helps to protect neurons from damage.

Glutatione depletion consequently leads to the death of additional

neurons.

Glutamate has six different types of receptors to which it can bind

in the brain. One of these receptors, the NMDA receptors, is tied to

calcium transport as its mode of action. In the case of the NMDA

receptors, the release of excess glutamate triggers an inflammatory

cascade that results in the death of neurons by the major influx of

calcium into the nerve until it results in neural cell death. Normal

levels of calcium result in normal neuron functioning. However,

excessive levels of calcium make it impossible for the neuron to

rest; the neuron continues to fire without stopping, causing the

release of inflammatory mediators, the release of more glutamate,

thus resulting in more calcium influx. The high intracellular levels

of calcium also lead to high levels of nitric oxide and

peroxynitrite, causing damage to the energy producing apparatus of

the cells. Magnesium is able to modulate the calcium flow, as is

zinc. However, zinc is a double-edged sword as it is also able to

activate glutamate release via the non-NMDA glutamate receptors.

Although these receptors are called " glutamate receptors " , any of

the excitatory amino acids are able to bind to the receptors and

cause excitotoxin damage. The toxic potential of these excitatory

amino acids has been suggested to be proportional to their ability

to excite neurons. These excitatory amino acids include glutamate,

aspartate, and to a lesser extent cysteine and homocysteine.

Glutamate and aspartate are common as food additives as well as

naturally occurring components of a large number of foods. In cells,

glutamate and aspartate can be synthesized from each other. The two

main food additives that are sources for excitotoxins are MSG

(monosodium glutamate) and aspartame (nutrasweet).

High levels of glutamate and aspartate are found naturally in

protein rich foods, including very high levels in wheat gluten, and

milk casein. While these amino acids are necessary for normal brain

function, excess amounts of them create a wide range of bodily

damage.

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