Talk:Excitotoxicity

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Contents 1 MSG 2 IF YOU ARE HEALTH CONSCIOUS, READ THIS: 3 Food Additives 4 List of excitotoxins 5 Controversies? 6 Source specificity 7 Major edit 8 Food additives 9 Why?

[edit] MSG

I don't know very much about this subject, so I apologize for any inaccuracies. I removed statements about the toxicity of MSG which lack mainstream scientific support, and which are adequately covered in that article. Molybdenumblue 14:12, 14 Apr 2005 (UTC)

[edit] IF YOU ARE HEALTH CONSCIOUS, READ THIS:

MSG as well as Aspartame are excitoxins. Look into research concerning aspartame in particular. If one looks on the sugar packets, one will find that there is a warning that this substance was found to cause cancer in tests. To be more specific about the effects, rats and monkeys that took aspartame in tests developed microscopic holes in their brains. Connect this to the concept of excitoxicity and you should come to the conclusion that Aspartame is in fact an excitoxin.

I apologize, i do not have much information about MSG but i do know it is an excitoxin. After all, glutamate is (in high concentrations) and MSG is "Monosodium GLUTAMATE". - Left unsigned by Musciotto

• Cancer and excitotoxicity are two very different things, so the logical leap between Aspartame causing cancer and being an excitotoxin makes no sense. Furthermore, if you are going to cite studies about "microscopic holes" please cite your references and be more specific. As far as MSG, yes in fact MSG is gutamate, however the majority of your brain cells also produce glutamate naturally and use it as a way to communicate amongst themselves. There is very little, if any, credible scientific evidence that the glutamate you ingest actually crosses over into your brain. Nrets 14:56, 5 December 2005 (UTC)

• • • Please read: Interview with Dr. Russell Blaylock on devastating health effects of MSG, aspartame and excitotoxins. This article and his expertise on this subject, and the article links should answer questions about this issue thoroughly. User:Nrets|Nrets needs to do alot more research before making such blanket,uninformed cause-and-effect statements. Left unsigned. —Preceding unsigned comment added by 64.230.233.197 (talk • contribs) 21:21, February 1, 2008

[edit] Food Additives

I removed the material related to the possible role of some food additives as neurotoxins. First, because it was copied directly from an article in a copyrighted journal. Second, because this wikipedia article is about the specific neurobiological process of excitotoxicity, not about neurotoxins (not all the toxins mentioned in the journal article are believed to work via excitotoxicity). If the editor wishes to expand on this material I would suggest starting a new article on that topic. Nrets 15:29, 12 December 2005 (UTC)

[edit] List of excitotoxins

I know the Aspartic Acid in aspartame is an excitotoxin. Shouldn't there be some sort of list of known excitotoxins on this page? Or is that on a different page? jess523s 00:43, 1 January 2006 (PST)

Maybe a cursory list would be appropriate, but the focus of the article should be on the process of excitotoxicity. In my opinion, for a comprehensive list of excitotoxins (and mechanisms of action) might be better suited for a separate article. Nrets 18:22, 1 January 2006 (UTC)

[edit] Controversies?

I would find it helpful if someone familiar with the field could identify current controversies surrounding excitotoxicity (e.g., is the cause of Delayed Calcium Deregulation still controversial, or has that been figured out?). Can anyone list some of these controversies? Or help me figure out where I can find out? Thanks much, delldot | talk 21:19, 21 March 2006 (UTC)

[edit] Source specificity

Should the source specificity controversy be addressed? It was sparked by papers in the early 90's by Tymianski et al. that showed that calcium influx through NMDARs, not calcium load itself, was what was harmful to the cell. Since then molecules linking nmdars to mediators of excitotoxicity such as nNOS have been found. I think it's interesting because it conflicts with the traditionally widely held belief that calcium load alone is what's harmful to the cell. But is this too obscure? Thanks, delldot | talk 20:00, 7 May 2006 (UTC)

[edit] Major edit

I've just finished a large edit, converting refs to the current <ref> style, mostly. I hope this is ok with everyone. I don't expect anyone will have any problems with it, but if you do, let me know. delldot | talk 06:25, 31 January 2007 (UTC)

[edit] Food additives

I'm a little concerned about the food aditive section. I think that this is a fairly marginal view. I don't believe that it is commonly accepted that excitotoxicity is involved in autism, though I admit I don't know. All of the stuff I find sketchy is from this one guy, Blaylock and his website DORway.com.

The argument that food additives such as MSG and aspartame are dangerous seems based around the idea that they can raise your blood plasma level of those amino acids in this article. But as I understand it, amino acids don't usually cross the blood brain barrier, so this doesn't produce a neurotoxic threat. These amino acids already exist in the bloodstream in much higher concentrations than the brain could handle; thus when the BBB is breached, e.g. in head trauma, this has been thought to be a possible contributing factor to the glutamate rise found in that condition. So anyway, I feel like this info might be misleading. I'd like to add content to the article about how amino acids don't cross the bbb and how increased blood plasma level of these amino acids is not necessarily harmful. I have some sources (e.g. Tsuchioka T, Fujiwara T, and Sunagawa M. Effects of glutamic acid and taurine on total parenteral nutrition. Journal of Pediatric Surgery. 2006 Sep;41(9):1566-1572. PMID 16952593. Retrieved on January 31, 2007) and will find others. I just wanted to put a note here so I could work with the other folks who maybe originally put this info in or have the opposite POV. I'm going to go ahead and add the info in when I have it all, but if there's any problem we can discuss it here. I'd also like to discuss removing the category:food safety, since I think it's at best tangentially related, and it's controversial (since you can't qualify something's membership in a category the way you can in a list, it has to be obvious and noncontroversial). Let me know if you want to discuss this further. Thanks, delldot | talk 17:21, 31 January 2007 (UTC)

The belief that excitotoxins can't cross the blood-brain barrier is the official position by the "scientific establishment" and the government regulatory agencies that have declared aspartame and msg safe. However, there are quite a lot of studies that are hard to explain without assuming BBB-leaks. Look at the references I mentioned in the section below for a more nuanced view. MaxPont 08:02, 24 July 2007 (UTC)

I have removed the following unsourced nonsense regarding soy protein excitotoxicity:

"Soy proteins are also increasingly suspected of being excitotoxins as more evidence makes clearer their effect on the body's hormones.^{[citation needed]} This has been studied with rats. Soy lecithin is likely the worst of all the soy proteins.^{[citation needed]}"

First of all, I can find no reliable sources to back the claim that soy is excitotoxic, although Dr. Russell Blaylock seems to be leading the specious crusade against hydrolyzed soy protein isolate without letting that pesky fact get in his way! It's possible he mentions some sources to back his claims in his reports...but these extremist, self-published documents are only available to paying subscribers. Second, not even Dr. Blaylock claims that soy excitotoxicity would be related to hormonal alterations. Finally, soy lecithin is not a protein at all, but rather a collection of lipids, some of which actually exhibit neuroprotective effects (see Aabdallah DM, Eid NI. "Possible neuroprotective effects of lecithin and alpha-tocopherol alone or in combination against ischemia/reperfusion insult in rat brain." J Biochem Mol Toxicol. 2004;18(5):273-8. PMID 15549708). I would be very interested to see any good evidence supporting the original claims, so by all means, let me know if some exists. St3vo (talk) 20:35, 18 January 2008 (UTC)

[edit] Why?

What evolutionary/physiological advantage would there be to have a neurotransmitter itself be a degenerative substance? It surely must be possible to have another neurotransmitter in its place (or deactivate the signal-trandsuction pathways which cause apoptosis). Correct me if I'm mistaken, but this makes no sense to me. - 2-16 15:10, 30 May 2007 (UTC)

This academic article could add insight here. If anyone can access the article it would be helpful to integrate the findings in the WP article:

REVIEW ARTICLE The role of excitotoxicity in neurodegeneration

Folia Neuropathol 2005; 43 (4): 322-339

authors: Elżbieta Salińska, Wojciech Danysz, Jerzy W. Łazarewicz,

Abstract:

A body of evidence suggests that the mechanisms of excitotoxic neuronal damage evoked by excessive or prolonged activation of the excitatory amino acid receptors may be involved in pathogenesis of brain damage in acute insults and in chronic neurodegenerative diseases. In this review we briefly discuss several selected mechanisms of the excitotoxicity, focusing attention on the role of ionotropic glutamate receptors, calcium transients and calcium-mediated cell injury. In the second part of this paper we provide information on elements of excitotoxicity in brain diseases.

keywords: calcium, excitatory amino acid receptors, neurodegeneration, NO, oxidative stress MaxPont 10:19, 23 June 2007 (UTC)

Here is the article: [1] MaxPont 10:32, 23 June 2007 (UTC)

Other references can be found from NIDAs Glutamate Cascade conference [2] [3]. A bit old but still useful.

Glutamate and the processes that lead to excitotoxicity are involved in a very important "learning" process, the "long term potentiation". Neurons respond to more input in a way that they become either more or less sensitive to incoming signals. By doing so the neural net is adjusted. That this process can also lead to cell death when it is disregulated due to pathological events has no evolutionary or physiological benefits. But in the healthy brain there should be no cells dying because of excitotoxicity. —Preceding unsigned comment added by 89.59.65.31 (talk) 14:09, 9 September 2007 (UTC)