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excitotoxic substances affect dendrites and neurons more than It is also important to note that neonatal exposure to MSG has axons, but axon demyelination has been demonstrated. During been shown to cause significant alterations in neuroendocrine the myelination process, each fibre tract has its own spatiotempo- function that can be prolonged.” By acting on the hypothala- ral pattern of development, accompanied by significant biochemi- mus and its connections to the remainder of the limbic connec- cal changes especially in lipid metabolism. tions, excitotoxins can profoundly affect behaviour. More recent studies have shown an even more complicated pat- tern of CNS myelination than previously thought. This is of | CONCLUSION: PREVENTING EXCITOTOXIC INJURY importance, especially as regards the widespread use of aspartame In this brief discussion of a most complicated and evolving sub- because of this triple toxin's effects on neuronal proteins and ject, I have had to omit several important pieces of the puzzle. DNA. Of special concern is aspartame's methanol component and For example, I have said little about the functional components of its breakdown product, formalde- the receptor systems, the glutamate hyde.*! Also, it is known that the transporter and its relation to ALS aspartate moiety undergoes sponta- and Alzheimer's dementia, receptor neous racemisation in hot liquids to decay with ageing and disease, mem- form D-aspartate, which has been | have also only briefly brane effects of lipid peroxidation associated with tau proteins in products, membrane fluidity, effects Alzheimer's disease.’ ** alluded to the toxicity of of chronic inflammation on the gluta- As you can see, the development of aspartame and omitted its mate/free-radical cycle, stress hor- the brain is a very complex process . mones and excitotoxicity, the role of that occurs in a spatial and temporal strong connection to insulin excess on the eicosanoid sys- sequence that is carefully controlled brain tumour induction tem, and the detailed physiology of by biochemical, structural as well as neurophysiological events. Even sub- tle changes in these parameters can produce ultimate changes in brain function that may vary from subtle the glutamatergic system. Ihave also only briefly alluded to the toxicity of aspartame and omitted its strong connection to brain tumour induction. alteration in behaviour and learning to autism, attention deficit T have tried to show the reader that there is a strong connection disorder and violence dyscontrol.™*** between dietary and endogenous excitotoxin excess and neurolog- Experiments in which infant animals were exposed to MSG have ical dysfunction and disease. Many of the arguments by the food demonstrated significant neurobehavioural defi *S Other stud- processing industry have been shown to be false. For example, ies have shown that when pregnant female animals were fed MSG, that dietary glutamate does not enter the brain because of exclu- their offspring demonstrated normal, simple learning but showed sion by the blood-brain barrier has been shown to be wrong, since significant deficits in complex learning, accompanied by profound glutamate can enter by way of the unprotected areas of the brain, reductions in several forebrain neurotransmitters.*’” In humans, such as the circumventricular organs. Also, as we have seen, this would mean that during infancy and early adolescence, learn- chronic elevations of blood glutamate can breach the intact blood- ing would appear normal; but with entry into a more advanced brain barrier. In addition, there are numerous conditions under education level, learning would be significantly impaired. In sev- which the barrier is made incompetent. eral ways, this animal model resembles ADD and ADHD in As our knowledge of the pathophysiology and biochemistry of humans. Kubo and co-workers found that neonatal glutamate the neurodegenerative diseases increases, the connection to could severely injure hippocampal CA1 neurons and dendrites and, excitotoxicity has become stronger.* This is especially so with as a result, impair discriminative learning in rats.”' the interrelationship between excitotoxicity and free radical It is also important to note that neonatal exposure to MSG has been shown to cause significant alterations in neuroendocrine function that can be prolonged.” By acting on the hypothala- mus and its connections to the remainder of the limbic connec- tions, excitotoxins can profoundly affect behaviour. | have also only briefly alluded to the toxicity of aspartame and omitted its strong connection to brain tumour induction. 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