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Does theanine inhibit memory and synaptic plasticity?

theanine ampa memory plasticity

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#1 michaelh

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Posted 30 January 2013 - 10:31 AM


Theanine has a low, micromolar affinity for AMPA & nmda antagonism? Nmda blockade has been linked with memory impairment, schizophrenia, cognitive impairment and synaptic plasticity inhibition. Also, long term depression is linked with lower ampa.


Here ares some qoutes from wiki:

In the regulated pathway, GluR1-containing AMPA receptors are trafficked to the synapse in an activity-dependent manner, stimulated by NMDA receptor activation. Under basal conditions, the regulated pathway is essentially inactive, being transiently activated only upon the induction of long-term potentiation.This pathway is responsible for synaptic strengthening and the initial formation of new memories.


Both GluR1 and GluR2 play an important role in synaptic plasticity. It is now known that the underlying physiological correlate for the increase in EPSP size is a postsynaptic upregulation of AMPARs at the membrane, which is accomplished through the interactions of AMPARs with many cellular proteins.



It inhibits MAPK. MAPK improves synaptic plasticity and memory.

On the flipside, Theanine increases LTP in the ca1 region.

Would homeostasis prevent some of these negative effects?

Edited by michaelh, 30 January 2013 - 10:38 AM.


#2 michaelh

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Posted 30 January 2013 - 03:32 PM

I would imagine the MAPK, AMPA & NMDA are upregulated after chronic theanine. Meaning theanine actually is positive for memory, cognition and plasticity.

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#3 peakplasma

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Posted 30 January 2013 - 07:19 PM

No, not necessarily. Synaptic Plasticity requires at least two things: LTP and LTD. You need both!

Long-term depression (LTD) is like Schumpeter's Gale - creative destruction. Our brains must clear some dentritic spines so that new ones can emerge and grow. A recent study I posted suggests that LTP is limited without some ratio of LTD.

Also, keep in mind not all Synaptic Plasticity is positive. For example, higher cases of epilepsy in urban populations can be attributed to air pollution-induced LTP.

Edited by peakplasma, 30 January 2013 - 07:20 PM.


#4 michaelh

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Posted 30 January 2013 - 07:26 PM

thanks.

Theanine has a low, micromolar affinity for AMPA & NMDA antagonism. NMDA blockade has been linked with memory impairment, schizophrenia, cognitive impairment. Also, depression is linked with lower ampa.

It inhibits MAPK. MAPK improves memory.

I would imagine the MAPK, AMPA & NMDA are upregulated after chronic theanine. Meaning theanine actually is positive for memory and cognition.

Edited by michaelh, 30 January 2013 - 07:26 PM.


#5 peakplasma

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Posted 30 January 2013 - 08:43 PM

Theanine has a low, micromolar affinity for AMPA & nmda antagonism? Nmda blockade has been linked with memory impairment, schizophrenia, cognitive impairment and synaptic plasticity inhibition. Also, long term depression is linked with lower ampa.

Theanine has a low, micromolar affinity for AMPA & NMDA antagonism. NMDA blockade has been linked with memory impairment, schizophrenia, cognitive impairment. Also, depression is linked with lower ampa.


Are you talking about long-term depression like being depressed? Or Long-Term Depression (LTD) in the context of synaptic plasticity. By definition, LTD is a relative decrease in AMPA relative to NMDA.

LTP involves the insertion of AMPA receptors at the synaptic membrane. LTD involves removing AMPA receptors from the synapse.The NMDA receptor number remains relatively constant, so it is the ratio of AMPA to NMDA receptors at the synapse that produces LTP or LDP (Lee, 2012)


So AMPA/NMDA antagonism itself is not relevant; what matters is the change in AMPAR relative to the NMDAR and the relative effects of the cascade on each. On top of that you would have to unravel the MAPK cascade and its relative effects.

#6 michaelh

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Posted 30 January 2013 - 10:49 PM

I mean't depressed depression (the miserable sort). How do I "unravel the MAPK cascade". Are you suggesting I need to do research, or that it hasn't been researched yet?

If theanine did have a negative effect, would the body not try and reverse it via homeostasis.

Aside from LTP or LDP, NMDA blockade has been linked with memory impairment, schizophrenia, cognitive impairment. Also, depression is linked with lower AMPA

Edited by michaelh, 30 January 2013 - 10:49 PM.


#7 Joe Cohen

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Posted 08 July 2013 - 03:14 AM

It's possible MAPK can be inhibited in the liver and activated in the brain. Theanine can work in different parts of the body in different ways.

#8 telight

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Posted 10 July 2013 - 03:57 PM

OP are you trying to say that taking theanine can lead to memory/cognitive impairment? There are studies such as this one: http://www.ncbi.nlm....pubmed/21303262 , that suggest that this is not the case. It is definitely not the case when taking theanine and caffeine

#9 Raptor87

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Posted 11 July 2013 - 01:58 AM

Remember to take inositol if you are going on beverages containing caffeine, I forgot this and my OCD is flaring up again.

http://www.ncbi.nlm....cles/PMC301012/
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#10 BobbyDick

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Posted 03 February 2016 - 09:53 PM

Does LTP make tolerance to positive effects (euphoria, stimulation, better cognition) of drugs (NDRI) and behavioral sensitization (stereotypies)?







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