Amyloid β-Mediated Zn2+ Influx into Dentate Granule Cells Transiently Induces a Short-Term Cognitive Deficit
Figure 6
Increase in Aβ-mediated Zn2+ influx.
(A) Brain slices were prepared 15 min after injection of saline containing ZnAF-2DA (100 pmol) and Aβ (25 pmol) in saline containing ZnAF-2DA (100 pmol) (1 µl) via an injection cannula and stained with calcium orange AM. Note that intracellular ZnAF-2 fluorescence was observed only in a few slices including the injected area in the dentate gyrus and not observed in the CA3 and CA1. G, dentate granule cell layer. H, hilus. Bars, 100 µm. (B) The data represent the ratios (%) of the fluorescence intensity after Aβ injection to that after saline injection that was expressed as 100% (n = 4). *, p<0.05 (t-test). (C) Hippocampal slices doubly stained with ZnAF-2DA and Calcium Orange AM were immersed in 400 µl ACSF containing 1500 nM ZnCl2. After measuring each baseline fluorescence for 10 sec, 100 µl of saline (n = 13), 50 µM Aβ in saline (n = 15), 50 µM Aβ +200 µM CNQX in saline (n = 8), and 50 µM Aβ +5 mM CaEDTA in saline (n = 8) was added to hippocampal slices in ACSF and both fluorescence was measured for 160 sec. The images of the dentate gyrus were obtained 160 s after addition. Bars; 50 µm. (D) The data represent the ratios (%) of the fluorescence after the addition (150–160 sec) to the baseline fluorescence (0–10 sec) that was expressed as 100%. *, p<0.05, vs. saline, #, p<0.05 (Tukey's test). No significant difference in calcium orange intensity, vs. saline (Dunnett's test).