Abstract: ObjectiveTo go deep into the mechanism of chronically aluminum-induced impairments to memory through observing the effects of chronic aluminum exposure on long-term potentiation(LTP)and studying the changes of Ca²⁺ concentration in hippocampus and protein kinase C.MethodsThe ablactated Wistar rats were used to establish the chronic-aluminium exposed models by the gavage of AlCl₃ of different concentrations in the drinking water to determine the levels of Al in brain,blood and intracellular calcium individually,and to measure the LTP in hippocampi of the rats three months later,and then determine the activity of protein kinase C(PKC)with modified Takai method.Results(1)The calcium concentration of AlCl₃ exposed groups was lower than that of control groups(P<0.01),but there was no distinctive difference between the AlCl₃ exposed groups.(2)The PKC activity of AlCl₃ exposed groups was obviously lower than that of control groups (P<0.01).ConclusionChronic aluminium exposure can decline the concentration of calcium in hippocampus and reduce the activity of PKC,thus affect the activity of its downstream kinases,damaging the formation of LTP and consequently impairing the ability of learning and memory.