title: Impairment of long-term potentiation induction is essential for the disruption of spatial memory after microwave exposure.
abstract: OBJECTIVE
  To assess the impact of microwave exposure on learning and memory and to explore the underlying mechanisms.
  
  
  METHODS
  100 Wistar rats were exposed to a 2.856 GHz pulsed microwave field at average power densities of 0 mW/cm(2), 5 mW/cm(2), 10 mW/cm(2) and 50 mW/cm(2) for 6 min. The spatial memory was assessed by the Morris Water Maze (MWM) task. An in vivo study was conducted soon after microwave exposure to evaluate the changes of population spike (PS) amplitudes of long-term potentiation (LTP) in the medial perforant path (MPP)-dentate gyrus (DG) pathway. The structure of the hippocampus was observed by the light microscopy and the transmission electron microscopy (TEM) at 7 d after microwave exposure.
  
  
  RESULTS
  Our results showed that the rats exposed in 10 mW/cm(2) and 50 mW/cm(2) microwave displayed significant deficits in spatial learning and memory at 6 h, 1 d and 3 d after exposure. Decreased PS amplitudes were also found after 10 mW/cm(2) and 50 mW/cm(2) microwave exposure. In addition, varying degrees of degeneration of hippocampal neurons, decreased synaptic vesicles and blurred synaptic clefts were observed in the rats exposed in 10 mW/cm(2) and 50 mW/cm(2) microwave. Compared with the sham group, the rats exposed in 5 mW/cm(2) microwave showed no difference in the above experiments.
  
  
  CONCLUSIONS
  This study suggested that impairment of LTP induction and the damages of hippocampal structure, especially changes of synapses, might contribute to cognitive impairment after microwave exposure.
authors.affiliation: Department of Experimental Pathology.
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.forename: Ruiyun
authors.initials: R
authors.lastname: Peng
authors.forename: Hongmei
authors.initials: H
authors.lastname: Zhou
authors.forename: Shuiming
authors.initials: S
authors.lastname: Wang
authors.forename: Yabing
authors.initials: Y
authors.lastname: Gao
authors.forename: Lifeng
authors.initials: L
authors.lastname: Wang
authors.forename: Zheng
authors.initials: Z
authors.lastname: Yong
authors.forename: Hongyan
authors.initials: H
authors.lastname: Zuo
authors.forename: Li
authors.initials: L
authors.lastname: Zhao
authors.forename: Ji
authors.initials: J
authors.lastname: Dong
authors.forename: Xinping
authors.initials: X
authors.lastname: Xu
authors.forename: Zhentao
authors.initials: Z
authors.lastname: Su
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D001831:Body Temperature; D018891:Dentate Gyrus / Q000502:physiology; D006624:Hippocampus / Q000473:pathology; D017774:Long-Term Potentiation / Q000528:radiation effects*; D008297:Male; D018782:Maze Learning / Q000528:radiation effects; D008568:Memory / Q000528:radiation effects*; D046529:Microscopy, Electron, Transmission; D008872:Microwaves / Q000009:adverse effects*; D011874:Radiometry; D051381:Rats; D017208:Rats, Wistar