title: Reduction of phosphorylated synapsin I (ser-553) leads to spatial memory impairment by attenuating GABA release after microwave exposure in Wistar rats.
abstract: BACKGROUND
  Abnormal release of neurotransmitters after microwave exposure can cause learning and memory deficits. This study investigated the mechanism of this effect by exploring the potential role of phosphorylated synapsin I (p-Syn I).
  
  
  METHODS
  Wistar rats, rat hippocampal synaptosomes, and differentiated (neuronal) PC12 cells were exposed to microwave radiation for 5 min at a mean power density of 30 mW/cm2. Sham group rats, synaptosomes, and cells were otherwise identically treated and acted as controls for all of the following post-exposure analyses. Spatial learning and memory in rats was assessed using the Morris Water Maze (MWM) navigation task. The protein expression and presynaptic distribution of p-Syn I and neurotransmitter transporters were examined via western blotting and immunoelectron microscopy, respectively. Levels amino acid neurotransmitter release from rat hippocampal synaptosomes and PC12 cells were measured using high performance liquid chromatograph (HPLC) at 6 hours after exposure, with or without synapsin I silencing via shRNA transfection.
  
  
  RESULTS
  In the rat experiments, there was a decrease in spatial memory performance after microwave exposure. The expression of p-Syn I (ser-553) was decreased at 3 days post-exposure and elevated at later time points. Vesicular GABA transporter (VGAT) was significantly elevated after exposure. The GABA release from synaptosomes was attenuated and p-Syn I (ser-553) and VGAT were both enriched in small clear synaptic vesicles, which abnormally assembled in the presynaptic terminal after exposure. In the PC12 cell experiments, the expression of p-Syn I (ser-553) and GABA release were both attenuated at 6 hours after exposure. Both microwave exposure and p-Syn I silencing reduced GABA release and maximal reduction was found for the combination of the two, indicating a synergetic effect.
  
  
  CONCLUSIONS
  p-Syn I (ser-553) was found to play a key role in the impaired GABA release and cognitive dysfunction that was induced by microwave exposure.
authors.affiliation: Department of Experimental Pathology, Beijing Institute of Radiation Medicine, Beijing, People's Republic of China.
authors.forename: Simo
authors.initials: S
authors.lastname: Qiao
authors.affiliation: Department of Experimental Pathology, Beijing Institute of Radiation Medicine, Beijing, People's Republic of China.
authors.forename: Ruiyun
authors.initials: R
authors.lastname: Peng
authors.affiliation: Department of Biochemical Pharmacology, Beijing Institute of Pharmacology and Toxicology, Beijing, People's Republic of China.
authors.forename: Haitao
authors.initials: H
authors.lastname: Yan
authors.affiliation: Department of Experimental Pathology, Beijing Institute of Radiation Medicine, Beijing, People's Republic of China.
authors.forename: Yabing
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Department of Experimental Pathology, Beijing Institute of Radiation Medicine, Beijing, People's Republic of China.
authors.forename: Changzhen
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Experimental Pathology, Beijing Institute of Radiation Medicine, Beijing, People's Republic of China.
authors.forename: Shuiming
authors.initials: S
authors.lastname: Wang
authors.affiliation: Department of Experimental Pathology, Beijing Institute of Radiation Medicine, Beijing, People's Republic of China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zou
authors.affiliation: Department of Experimental Pathology, Beijing Institute of Radiation Medicine, Beijing, People's Republic of China.
authors.forename: Xinping
authors.initials: X
authors.lastname: Xu
authors.affiliation: Department of Experimental Pathology, Beijing Institute of Radiation Medicine, Beijing, People's Republic of China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Department of Experimental Pathology, Beijing Institute of Radiation Medicine, Beijing, People's Republic of China.
authors.forename: Ji
authors.initials: J
authors.lastname: Dong
authors.affiliation: Department of Radiation Protection and Health Physics, Beijing Institute of Radiation Medicine, Beijing, People's Republic of China.
authors.forename: Zhentao
authors.initials: Z
authors.lastname: Su
authors.affiliation: Endocrine and Cardiovascular Center, Cardiovascular Institute and Fuwai Hospital of Chinese Academy of Medical Sciences, Beijing, People's Republic of China.
authors.forename: Xinxin
authors.initials: X
authors.lastname: Feng
authors.affiliation: Department of Experimental Pathology, Beijing Institute of Radiation Medicine, Beijing, People's Republic of China.
authors.forename: Lifeng
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Experimental Pathology, Beijing Institute of Radiation Medicine, Beijing, People's Republic of China.
authors.forename: Xiangjun
authors.initials: X
authors.lastname: Hu
mesh_terms: D000818:Animals; D008297:Male; D008569:Memory Disorders / Q000235:genetics / Q000378:metabolism*; D008872:Microwaves / Q000009:adverse effects*; D016716:PC12 Cells; D010766:Phosphorylation; D051381:Rats; D017208:Rats, Wistar; D065852:Spatial Memory / Q000502:physiology*; D016704:Synapsins / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
chemical_list: D016704:Synapsins; D005680:gamma-Aminobutyric Acid
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