Intracellular Zn2+ levels are decreased in brain sections from AD cases. A) Zinc ions were visualized by Zinpyr-1 and the fluorescence of intracellular Zn2+ staining measured in AD patient and control sections (see Table 1). The mean Zinpyr-1 grey values of cells of 10 optical fields of view from AD and Control cases are shown (a, right panel). The intracellular Zn2+ concentration is significantly decreased in sections of AD patients. B) Although the intracellular Zn2+ concentration is decreased in AD, an enrichment of Zn2+-ions can be found colocalizing with extracellular Aβ plaques (arrow) in AD patient brain sections.