Figure 4.
The enhancement of synaptic plasticity and memory by picomolar concentrations of Aβ42 involves α7-nAChRs. A, Hippocampal slices perfused with MCL (3 μm) concurrent with human Aβ42 (200 pm) and d-APV (50 μm) no longer display the Aβ-induced PTP enhancement. The horizontal bars indicate the period of perfusion with MCL, Aβ, and APV. B, Hippocampal slices perfused with α-BgTx (0.1 μm) concurrent with human Aβ42 (200 pm) and D-APV (50 μm) no longer display the Aβ-induced PTP enhancement. The enhancement is still present after washout of α-BgTx if slices are perfused again with Aβ42 (200 pm). The horizontal bars indicate the period of perfusion with α-BgTx, Aβ, and APV. C, Perfusion of hippocampal slices with human Aβ42 (200 pm) for 20 min before tetanus does not increase LTP in slices from α7-KO mice, whereas it still enhances potentiation in slices from WT littermates. BST was normal in the α7-KO mice (data not shown). The horizontal bar indicates the period of perfusion with Aβ. D, E, Bilateral injections of human Aβ42 (200 pm) into dorsal hippocampi, 15 min before training, do not enhance reference or contextual memory in α7-KO mice, whereas they still enhance memory in WT littermates.