Dysregulation of Ca2+ homeostasis in Alzheimer's disease: role in acetylcholinesterase production and AMPA receptor internalization

Amyloid-β (Aβ)-induced Ca²⁺ influx into neurons has been well described since it was first reported almost 20 years ago. Ca²⁺ influx can disrupt mechanisms of long-term potentiation and long-term depression and increase neuronal susceptibility to excitotoxicity. Our studies show that Aβ also causes an increase in acetylcholinesterase (AChE) levels and induces AMPA receptor internalization through Ca²⁺-dependent mechanisms. As Aβ-induced Ca²⁺ entry may increase neuronal excitability, the increase in AChE and the downregulation of cell surface AMPA receptors may be part of a homeostatic mechanism which maintains normal levels of cholinergic and glutamatergic signaling.