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NDMA Agonist

>>NMDA antagoinst>>

There's your answer (well in the sense that is pertinent to this thread).
So who wants to be next to confuse agonism and antagonism? :)

ebola
 
it seems that it doesn't matter whether NMDAR antagonists or agonists are used, both seem to be able to kick the brain out of a depressive state, it might be all that is required is a change in the activity level,all that is required if this is the case is a thorough hit to the glutamate system : 'pharmaceutical ECT', and the beneficial effects are due to the rewiring resulting from the wallop rather than any lasting chemical effects.

not all NMDAR agonists are bad D-cycloserine a glycine/serine site NMDA agonist is anxiolytic and allegedly nootropic as well as sometimes beng an antidepressant. it has been widely used as a tuberculostatic. I believe it was this drug that lead to the recent interest in ketamine as an antidepressant.

I really don't think MSG is addictive, there is already plent of glutamate in the brain, any excess would rapidly. The taste sensation of umami is the reason for MSG's popularity, some diets are lacking in this flavour.
 
Umame.

Is one of you MSG-ites confusing monosodiumglutamate with L-theanine (the latter of which, I believe, is a weak NMDA antagonist?).

I was under then influence that L-theanine is umame.

As a side note - I find pure L-theanine to be slightly anti-depressant, and definitely VERY sedative (on par with Lorazepam).

For the sake of science, next time I'm in the bulk food store I'll grab a gram of MSG and experiment with little ammounts. Its on YOUR head if I get a depressive episode ;)
 
No, it's conjugated glutamates (otherwise green tea would taste like shit). The flavour was originally found in dried shiitake mushrooms.

edit: Ah, nm, I looked it up in google (umami rather than umame) and it says it is the same sort of flavour.. Which is strange because green tea and MSG taste nothing alike.
 
MSG isn't addictive. It can't cross the BBB unless you're BBB is damaged.
MSG doesn't make everything taste nice, it's just got that umami flavor that some people like.

I add MSG to lots of things I cook; soups, gravy, fried rice.
 
>>The flavour was originally found in dried shiitake mushrooms.>>

I thought it was kombu (kelp).
Ah well...doesn't matter. Each have those free glutamates that do the trick.

ebola
 
Jamshyd said:
I still all you people are talking about is L-Theanine, not MSG or any glutamate.

http://pdrhealth.com/drug_info/nmdrugprofiles/nutsupdrugs/lth_0296.shtml

or

http://en.wikipedia.org/wiki/L-theanine

for example.

It is L-Theanine that defines the Umame taste, and it is L-Theanine that is found in tea and in Shiitake.
Click to expand...

my understanding is that both l-threonine and glutamate (and several other compounds too) bind to the same taste receptor, structurally they are only a gnats apart, which is a G-coupled receptor very very similar to the brain glutamate receptors but rather less sensitive, (leads to the thought would tasting umami lead to a bioassay for glutamate agonism in NCE's.) I also believe that this receptor is sensitive to certain metal ions, in particular zinc ions.
t makes sense that humans have a sensor for glutamate as this is one of the most common AA's and therefore is likely to be present in most proteins which themselves are mostly insoluble and therefore tasteless, so it acts as a marker for protein taste.
the original isolation of the taste was from kombu seaweed and the active agent there is most certainly glutamate. MSG is the cheapest and easiest way of achieving this flavour, hence its popularity.
there also appear to be indications of genetic variance in the prevalence or sensitivity of the receptor between races, with asiatic people beng able to detect lower concentrations of glutamate than caucasians.
 
Ah, thanks for the explanation :).

Your point about zinc is very interesting, since zinc is an important cofactor (or whatever you wanna call it. Sidekick?) of the NMDA-receptor complex.
 
Pirictiram: I was given that in The Netherlands, I had terrible nightmares.
 
Do you mean Piracetam?

I have tried its analogues, Oxiracetam and Nefiracetam. Both blocked the effects of Ketamine (ex. 100mg iv produced a little rush that lasted 5 or so mins whereas this dose would have knocked me out for at least 30mins without the -racetam's blocking effect).

I did mention in many other threads that both -racetams make me very, very depressed after max. 4 days of use.

And btw, in its typical ambiguous terms, most research on -racetam drugs says something to the effect of these drugs "increasing NMDA currents" - whatever that means. I doubt the authors even know what it means!
 
Jamshyd said:
Ah, thanks for the explanation :).

Your point about zinc is very interesting, since zinc is an important cofactor (or whatever you wanna call it. Sidekick?) of the NMDA-receptor complex.
Click to expand...

indeed it seems that zinc can modify the activity of many GPCR's including NMDA receptors, I think that zinc acts as anti sodium but I cannot remember whether it increases or decreases receptor activity, it might vary depending on the receptor type?
the effect of zinc on taste receptors was suggested as a reason for the strange taste of aqueous zinc solutions, for me it is sour metallic and rather familiar. soluble calcium as calcium chloride has a similar taste.
zinc is also crucial to the olefactory receptors, I vaguely remember experiments where chelating the zinc out or perhaps it was simply not supplied in food caused loss of the sense of smell.
 
There is no way you're tasting glutamate in a protein, 2/3 of the functionality is in covalent linkages and what little there is in the mass of the protein, a significant portion is buried.
 
Jamshyd said:
Do you mean Piracetam?

I have tried its analogues, Oxiracetam and Nefiracetam. Both blocked the effects of Ketamine (ex. 100mg iv produced a little rush that lasted 5 or so mins whereas this dose would have knocked me out for at least 30mins without the -racetam's blocking effect).

I did mention in many other threads that both -racetams make me very, very depressed after max. 4 days of use.

And btw, in its typical ambiguous terms, most research on -racetam drugs says something to the effect of these drugs "increasing NMDA currents" - whatever that means. I doubt the authors even know what it means!
Click to expand...

the blocking of ketamine effects is interesting and difficult to explain, as ketamine is a non competitive antagonist, a channel blocker wheras the racetams, if indeed they do act NMDA receptors, due to their similarity to the gluatamate apartate structure are acting at the glutamate (NMDA) site, unless of course the racetams bind to the high affinity PCP site in the channel that ketamine binds to but do not elicit any effect other than preventing ketamine from binding.
I think some thnking about this is needed!
V
 
kidamnesiac said:
There is no way you're tasting glutamate in a protein, 2/3 of the functionality is in covalent linkages and what little there is in the mass of the protein, a significant portion is buried.
Click to expand...

there are free amino acids in most crude protein preparations, such as you eat every day, due to hydrolysis. I said that proteins themselves are tasteless but they contain free AA's that are used as taste cues for protein. glutamate is one of the most common AA's ergo it is likely to be found free in partially hydrolysed proteins.
 
Perhaps the action of the -racetams on NMDA channels is through allosteric modulation?

I really have a hard time figuring out what "increasing NMDA currents" means.

Btw, I am not the first person to report a sharp reduction of the effects of NMDA-antagonists with the use of -racetams.

Neither am I the first person to report depression after continued use of -racetams.

And most importantly, I am not the only person who claims that NMDA-antagonists, especially Ketamine, have a positive effect on melancholic mood ;)

[yes, I like to push pro-Ketamine statements like that! haha]



If I remember correctly, the pressence of zinc in NMDA channels has a similar role to Mg+ which is the same as, in the way you put it ("Anti-sodium") :)
 
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