It has been suggested that oligomers of Amyloid-beta (oAβ)42 are responsible for the impairment of synaptic plasticity and memory, whereas monomeric forms of Aβ42 (mAβ42) or Aβ40 are involved in physiological functions. However, our previous works have demonstrated that both mAβ42 and oAβ42 were able to exert a positive effect on synaptic plasticity and memory. Here, we aimed to clarify whether different effects of Aβ on long-term potentiation (LTP) are mediated by Aβ42 or Aβ40 in monomeric or oligomeric forms. We performed electrophysiological experiments on hippocampal mouse slices in vitro. LTP was recorded at CA3-CA1 connections after a treatment with different solution enriched in monomers or oligomers of Aβ42 or Aβ40 at low (200 pM) or high (200 nM) concentrations. We demonstrated that only administration of 200 pM oAβ42 was able to induce an increase of hippocampal LTP, whereas 200 nM oAβ42, mAβ42 or oAβ40 impaired it. An ultrastructural characterization of the 200 nM and 200 pM oAβ42 solutions by Transmission Electron Microscopy showed that both preparations contained monomers as well as oligomers, but with a different ratio. This structural and functional characterization of the peptide suggests that oAβ42 is able to exert a physiological or pathological effect depending upon the dose and the relative concentration of Aβ species, and that oligomers play a role also in physiological conditions.
|Titolo:||Both monomers and oligomers of Amyloid-β peptide are involved in synaptic plasticity in physiological and pathological conditions|
|Data di pubblicazione:||2017|
|Appare nelle tipologie:||4.2 Abstract in Atti di convegno|