FIGURE 7.

Blockade of Aβ induced increases in intracellular calcium and synaptic transmission by a small peptide. A, effect of several calcium channel blockers on the increase in intracellular calcium, measured with Fluo-3, induced by the application of 500 nm Aβ with a puffer pipette (indicated by a horizontal line in Fig. 6A). The concentrations of the blockers were 1 μm CNQX, 50 μm d-AP5, 1 μm conotoxin, 1 μm agatoxin, 3 μm nifedipine, and 100 μm Na7. The effects were normalized with respect to control (p < 0.05). B, result of lowering calcium influx using a nominally Ca²⁺ free solution or 1 mm EGTA on the early and chronic effects of Aβ on miniature current frequency from three independent experiments (p < 0.05). For these experiments, the neurons were exposed to Aβ alone or in the presence of 100 μm Na7. C and D, effect of Aβ-induced reduction on SV2 in the presence and absence of Na7, Na13, and Na15. The bars are mean ± S.E. from nine different neurons (p < 0.05).