Figure 6.
Temporal analysis of synaptotoxicity caused by Aβ1-42 and neuroprotection by blockade of adenosine A2A receptors. Hippocampal neurons were preincubated with the A2AR antagonist SCH58261 (50 nm) 15 min before addition of 500 nm Aβ1-42. Hippocampal neurons were double-labeled for MAP-2 (red) and synaptophysin (green) after 12 h (A), 24 h (B), and 48 h (C) of incubation and analyzed by confocal microscopy. Magnification, 400×. Aβ1-42 causes a decrease of MAP-2 and synaptophysin immunoreactivities at all type points, which is prevented by SCH58261 and is not mimicked by the nonamyloidogenic scrambled peptide Aβ42-1. D, Western blot analysis (15 μg of protein loaded in each lane) quantifying the loss of synaptophysin and SNAP-25 immunoreactivities in cultures treated with Aβ, which is prevented by SCH58261 (data are mean ± SEM of 6 independent cultures; *p < 0.05). E, Time course analysis of the extracellular levels of adenosine (quantified by HPLC) in hippocampal neurons incubated with Aβ (data are mean ± SEM of 5 independent cultures; *p < 0.05).