Long term potentiation and long term depression

[Marc Gillespie]

Hi All,

See comments below.

On Mar 23, 2006, at 1:02 PM, Doug howe wrote:

> Erika,
>  You are correct that LTP (Long Term Potentiation) and LTD (Long  
> Term Depression) both reflect changes in synaptic activity (at the  
> level of individual synapses) over the long term (at least  
> hours...ranging up to weeks or more).  So a GO term like GO:0048172  
> (regulation of short-term neuronal synaptic plasticity) will not be  
> useful for LTD or LTP.  Further, LTP and LTD are the results of  
> synaptic plasticity...they are not the plasticity itself, so terms  
> like "positive regulation of synaptic plasticity" will not be  
> useful either I don't think.
>
> It looks to me like new terms would be needed to represent LTP and  
> LTD specifically.
>
> I propose the following...open for discussion...
>
> positive regulation of synaptic transmission (GO:0050806)
> ---[i]long term potentiation (GO:new)
>
> negative regulation of synaptic transmission (GO:0050805)
> ---[i]long term depression (GO:new)

I am not sure I understand. Are these terms describing:

1) a specific type of regulation encompassed by (children of)  "GO: 
0048169 regulation of long-term neuronal synaptic plasticity"

or

2) are they meant to describe something other than plasticity?

I am ok with 1, but disagree with 2. I would not want to classify LTP  
and LTD without implying plasticity. Seems like plasticity is to  
amorphous a term, though I did like "neuroadaptation". Though I  
probably like it not because it is any-less amorphous, but rather it  
carries less historical baggage.

Marc

Marc Gillespie
Cold Spring Harbor Laboratory
Stein Lab
1 Bungtown Road
Cold Spring Harbor, NY 11724

email: gillespm at cshl.edu
telephone: (718) 990-5249

http://www.reactome.org



>
>
>
> Thoughts from anyone else?
>
> -Doug
>
>
> erika wrote:
>> Dear all,
>> I am annotating ionotropic gluatamate receptor and I would like to  
>> insert terms about long term potentiation (LTP) and long term  
>> depression (LTD).
>> I know that there are these two terms that described two form of  
>> synaptic plasticity.
>>  GO:0048169 regulation of long-term neuronal synaptic plasticity:  
>> A process that modulates long-term neuronal synaptic plasticity,  
>> the ability of neuronal synapses to change long-term as  
>> circumstances require. Long-term neuronal synaptic plasticity  
>> generally involves increase or decrease in actual synapse numbers.
>>
>> GO:0048172 regulation of short-term neuronal synaptic plasticity:  
>> A process that modulates short-term neuronal synaptic plasticity,  
>> the ability of neuronal synapses to change in the short-term as  
>> circumstances require. Short-term neuronal synaptic plasticity  
>> generally involves increasing or decreasing synaptic sensitivity.
>>
>> So I can not understand if we should add new terms about LTP and  
>> LTD or we could use GO:0048172 (regulation of short-term neuronal  
>> synaptic plasticity) and GO:0048169 (regulation of long-term  
>> neuronal synaptic plasticity) for LTP and for LTD
>> This is a new topic for me so any help will be appreciated.
>> I have read that LTD is a weakening of a synapse that lasts from  
>> hours to days. So I am not sure that short term plasticity could  
>> be the correct term for LTD because GO:0048172 (regulation of  
>> short-term neuronal synaptic plasticity) describes changes in the  
>> short time. LTD results from either strong synaptic stimulation  
>> (as occurs in the cerebellum Purkinje cells) to persistent weak  
>> synaptic stimulation (as in the hippocampus).
>> In addiction, LTD refers only to a weakening of a synapse and not  
>> to an increasing of it.
>> LTD is thought to result from changes in postsynaptic receptor  
>> density, although changes in presynaptic release may also play a  
>> role. Slow, weak stimulation of CA1 neurons also brings about long- 
>> term changes in the synapses, in this case, a reduction in the  
>> sensitivity. It involves Glu binding to a different type of NMDA  
>> receptor.
>> Instead, long-term potentiation (LTP) is the long-lasting  
>> strengthening of the connection between two nerve cells.  
>> Experimentally, a series of short, high-frequency electric  
>> stimulations to a nerve cell synapse can strengthen, or  
>> potentiate, that synapse for minutes to hours. In living cells,  
>> LTP occurs naturally and can last from hours to days, months, and  
>> years. The biological mechanisms of LTP, largely via the interplay  
>> of protein kinases, phosphatases, and gene expression, give rise  
>> to synaptic plasticity and provide the foundation for a highly  
>> adaptable nervous system.
>> Researches in Geneva, Switzerland have demonstrated that formation  
>> of LTP in rat brains coincides with the formation of additional  
>> synapses (at least one more) between the presynaptic axon terminal  
>> and the dendrite it synapses with. (Report by Toni, N., et al,  
>> Nature, 25 Nov 99). Presumably this, too, increases the efficiency  
>> of synaptic transmission.
>> I am confused because both LTP and LTD refer to changes in the  
>> long term.
>> So are they part of process of regulation of ONLY long term  
>> synaptic plasticity regulation GO:0048169?
>>  Thanks very much
>> Erika
>> Erika Feltrin, PhD student
>>
>> Bioinformatics Lab-CRIBI
>>
>> Padua University
>>
>> erika at cribi.unipd.it <mailto:erika at cribi.unipd.it>
>>
>>
>> c/o EMBL-European Bioinformatics Institute
>>
>> Wellcome Trust Genome Campus
>>
>> Cambridge CB10 1SD
>>
>> United Kingdom
>>
>>
>>  erika at ebi.ac.uk <mailto:erika at ebi.ac.uk>
>>
>> +44 (0) 1223 492600 (work)
>>
>>
>>
>>

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