title: Effects of subchronic aluminum exposure on spatial memory, ultrastructure and L-LTP of hippocampus in rats.
abstract: Epidemiological investigations have indicated that aluminum (Al), as an important environmental neurotoxicant, could cause damage to the cognitive function which was closely related with neurodegenerative diseases. Long-term potentiation (LTP) is one form of synaptic plasticity in association with cognitive function. Previous studies have demonstrated that Al impaired early phase long-term potentiation (E-LTP) in vivo and in vitro. However, Al-induced damage to late phase long-term potentiation (L-LTP) has poorly been studied. The present study was designed to observe the effects of subchronic Al exposure on the spatial memory, hippocampus ultrastructure and L-LTP in rats. Pregnant Wistar rats were assigned to four groups. Neonatal rats were exposed to Al by parental lactation from parturition to weaning for 3 weeks and then fed with the distilled water containing 0, 0.2%, 0.4% and 0.6% aluminum chloride (AlCl3) respectively from weaning to postnatal 3 months. The levels of Al in blood and hippocampus were quantitated by atomic absorption spectrophotometer. Morris water maze test was performed to study spatial memory. The induction and maintenance of L-LTP in area of Schaffer collateral- CA1 synapse was recorded by extracellular microelectrode recording technology in hippocampus of experimental rats. Hippocampus was collected for transmission electron microscopy observation. The results showed that the Al concentrations in blood and hippocampus of Al-exposed rats were higher than those of the control rats. Al could impair spatial memory ability of rats. Neuronal and synaptic ultrastructure from Al-exposed rats presented pathological changes; the incidence of L-LTP has a decrease trend while population spike (PS) amplitude was much smaller significantly stimulated by high-frequency stimulation (HFS) in Al-exposed rats. Our findings showed that Al exposure caused spatial memory damage, under which the neuronal and synaptic ultrastructure changes maybe were their morphological basis and the impaired L-LTP of hippocampus could be their electrophysiological basis.
authors.affiliation: Department of Toxicology, School of Public Health, China Medical University, China.
authors.forename: Lifeng
authors.initials: L
authors.lastname: Zhang
authors.forename: Cuihong
authors.initials: C
authors.lastname: Jin
authors.forename: Qiufang
authors.initials: Q
authors.lastname: Liu
authors.forename: Xiaobo
authors.initials: X
authors.lastname: Lu
authors.forename: Shengwen
authors.initials: S
authors.lastname: Wu
authors.forename: Jinghua
authors.initials: J
authors.lastname: Yang
authors.forename: Yanqiu
authors.initials: Y
authors.lastname: Du
authors.forename: Linlin
authors.initials: L
authors.lastname: Zheng
authors.forename: Yuan
authors.initials: Y
authors.lastname: Cai
mesh_terms: D000077410:Aluminum Chloride; D017607:Aluminum Compounds / Q000378:metabolism / Q000633:toxicity*; D000818:Animals; D002712:Chlorides / Q000378:metabolism / Q000633:toxicity*; D003071:Cognition / Q000187:drug effects*; D004195:Disease Models, Animal; D005260:Female; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology / Q000648:ultrastructure*; D017774:Long-Term Potentiation / Q000187:drug effects*; D008297:Male; D008568:Memory / Q000187:drug effects*; D008569:Memory Disorders / Q000139:chemically induced* / Q000473:pathology* / Q000503:physiopathology; D046529:Microscopy, Electron, Transmission; D009473:Neuronal Plasticity / Q000187:drug effects; D011247:Pregnancy; D051381:Rats; D017208:Rats, Wistar; D013569:Synapses / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure
chemical_list: D017607:Aluminum Compounds; D002712:Chlorides; D000077410:Aluminum Chloride