Figure 1.
Spontaneous synchronous calcium oscillations are abolished by hAPP expression. A, B, F, G, Simultaneous traces of [Ca2+]i in three cells of a coverslip, measured with Fura-2 AM expressed as R/Rmean, were R is the ratio of F340/F380 and Rmean is the mean ratio value after 2 min recording. A, At 7 DIV, rat cortical neurons do not present calcium oscillations. B, After 13 DIV, neurons show spontaneous, synchronized calcium oscillations. C, In a neuronal network labeled by an anti-MAP-2 antibody (red), infection by AdAPPGFP allows APP and GFP (green) expression in a subset of neurons. D, Primary cortical neuron infected by AdAPPGFP, coexpressing GFP (green) and hAPP, labeled with hAPP specific monoclonal antibody, WO-2 (red). Scale bar, 20 μm. E, Western blot analysis of cell lysates (top panel) or culture media (bottom panel), from rat cortical neurons infected or not (NI) by Adβgal (βgal), AdAPPGFP (APP), or AdAPPswe (APPswe). Protein loading was controlled using rabbit actin antiserum. F, Neuronal network infected by Adβgal show spontaneous calcium oscillations, whereas in a network infected by AdAPPGFP or AdAPPswe, calcium oscillations are abolished (G, H).