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Long term potentiation and long term depression

Doug howe dhowe at cs.uoregon.edu
Thu Mar 23 10:02:22 PST 2006


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)



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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