Effects of the neurotrophic agent T-817MA on oligomeric amyloid-β-induced deficits in long-term potentiation in the hippocampal CA1 subfield

Formation of oligomeric amyloid-β (oAβ) is 1 of the most likely causes of Alzheimer's disease (AD). We hypothesized that in the early phase of AD, cognitive impairments observed before marked neuronal loss and brain atrophy might be associated with oAβ-induced synaptic dysfunction. T-817MA [1-{3-[2-(1-benzothiophen-5-yl)ethoxy]propyl}azetidin-3-ol maleate] has both neuroprotective and neurotrophic effects and is used to treat AD. Although T-817MA has been shown to ameliorate amyloid-induced learning deficits in experimental AD models, it remains unclear whether this drug would be able to prevent oAβ-induced synaptotoxicity. In the present study, we investigated the effects of T-817MA on the disturbances in synaptic plasticity induced by oAβ42 and oligomeric photo-cross-linked Aβ42 (oXLAβ42) in a slice preparation of the CA1 subfield of mouse hippocampus. Both oAβ42 and oXLAβ42 treatments significantly reduced the induction of long-term potentiation (LTP). In addition, oAβ42 treatment significantly facilitated long-term depression (LTD). Treatment with T-817MA ameliorated the LTP reduction; however, T-817MA treatment did not inhibit the facilitation of LTD induction by oAβ42. These results suggest that T-817MA reverses oAβ-induced LTP reduction as it may occur in the early phase of AD.