Effect And Mechanism Of Aβ On Ampa Receptor Subunits In Rat Hippocampal Neurons

Background: In recent years, many evidences indicated that beta-amyloid is one of the most important factors in AD. However, it is unclear that whether beta-amyloid affects AMPA receptor subunits of the cultured rat hippocampal neurons. The aim of this experiment is to examine the effects of beta-amyloid on AMPA receptor subunits expression.Methods: First, the immunofluorescence method was adopted to identify the toxicity of Aβ_25-35 on hippocampal neurons. Then, immunofluorescence method and Western blotting were used to examine the effects of AMPA receptor subunits on the rat cultured hippocampal neurons.Results: Immunofluorescence method showed that Aβ_25-35 increased apoptosis of rat cultured hippocampal neurons. Western blotting indicated that total protein level of AMPA receptor subunits GluR1, GluR2, GluR3 decreased and GluR2 membrane protein level also decreased but the expression of GluR1 on the membrane increased.Conclusion: Aβ_25-35 concentration of 25μM has a cytotoxicity of rat cultured hippocampal neurons. Aβinduced total protein level of AMPA receptor subunits decreased, facilitated GluR2 subunit removal from the synaptic site, and increased the expression of GluR1 subunit on the surface of neurons. Background: The aim of this part is to exam the mechanism of Aβ_25-35 modulation on AMPA subunits expression in rat hippocampal neurons.Methods: We first treated hippocampal neurons with hypertonic sucrose to disrupt formation of clathrin cages and block clathrin-mediated AMPA receptor endocytosis. Then western blotting was adopted to investigate membrane protein level of GluR2 subunit.Results: Hypertonic sucrose (0.45M, applied for 20 min before Aβ_25-35) abolished Aβ_25-35 induced reduction in surface and synaptic GluR2 subunit expression.Conclusion: Aβ_25-35 elicited GluR2 reduction at synapses is mediated by clathrin-dependent endocytosis.