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2010-07-05 - Colloque/Abstract - Anglais - 1 page(s)

Villers Agnès , Godaux Emile, Ris Laurence , "Proteins synthesized in dendrites can sustain local long-lasting long term potentiation (L-LTP) but cannot be captured by other synapses" in 7th Forum of Neuroscience, vol.5, 103.67, Amsterdam, The Netherlands, 2010

  • Codes CREF : Neurophysiologie (DI3224)
  • Unités de recherche UMONS : Neurosciences (M119)
  • Instituts UMONS : Institut des Biosciences (Biosciences)

Abstract(s) :

(Anglais) Long-term potentiation (LTP) is a lasting increase in synaptic strength induced by high frequency stimulation (HFS) of the related presynaptic fibers. In the CA1 region of mice hippocampal slices, a strong tetanic stimulation triggers a long-lasting long-term potentiation (L-LTP), which requires protein synthesis for the development of its late phase. It was first believed that all these proteins were synthesized in the soma. However, more recently, it was proved that translation of mRNAs could also take place in dendrites. Hence the first question asked here: is dendritic protein synthesis able to sustain an LTP lasting more than 2-3 hours? Here, L-LTP was elicited in hippocampal slices by delivering 4 trains of HFS to the Schaffer's collaterals while monitoring the resulting excitatory postsynaptic potential field (fEPSP) every 15 min for 8 hrs in the CA1 region. We took advantage of the fact that, in CA1 pyramidal cells, it is possible to sever the dendrites from their somas. So we were able to compare the LTP obtained on isolated dendrites to that observed on intact dendrites. We report that, in CA1 dendrites separated from their cellular bodies, a strong stimulation induces an L-LTP lasting as long as 8 hours and requiring dendritic protein synthesis. In intact slices, the late LTP elicited in one pathway by a strong stimulation can be captured by another pathway activated only by a weak stimulation. The current hypothesis is that a weak stimulation creates a synaptic tag which is able to capture plasticity-related proteins synthesized in the soma. The second question asked: can L-LTP induced in isolated dendrites be transferred to weakly activated synapses? We report that synaptic capture-mediated L-LTP cannot happen in isolated dendrites. Taken together, these results suggest that synaptic capture observed in intact slices is dependent on proteins produced through transcription and/or somatic translation.