title: Uremia-caused changes of ghrelin system in hippocampus may be associated with impaired cognitive function of hippocampus.
abstract: OBJECTIVE
  Hippocampus plays an important role in spatial learning and memory. Ghrelin, a brain-gut peptide, participates in the mnestic functions of hippocampus through its receptor growth hormone secretagogue receptor (GHS-R) distributed in hippocampus. This study was to investigate whether there was a correlation between the changes of ghrelin system in hippocampus and the spatial cognitive impairment caused by chronic renal failure (CRF).
  
  
  METHODS
  Sprague-Dawley rats (male, 180 ± 10 g, 7-8 weeks old) were randomly classified into CRF group and control group (n = 18 per group). The CRF model was constructed by 5/6 nephrectomy and the controls treated with sham operation. By the 8th week after the surgery, the spatial cognitive function of rats was assessed by Morris water-maze test (MWM), the protein expression of ghrelin and GHS-R in the hippocampus by immunohistochemistry, and the mRNA expression by real-time PCR. Statistical analysis was performed using ANOVA, Student-Newman-Keuls-q test and Pearson correlation analysis, and P < 0.05 was considered significant.
  
  
  RESULTS
  Compared with the controls, the time spent in "platform" quadrant (TSPQ) of rats with CRF was decreased, but the escape latency (EL) was increased significantly in MWM, and meanwhile the protein and mRNA expression of ghrelin and GHS-R in hippocampus was also increased significantly (P < 0.05 or P < 0.01). Correlation analysis suggested that the TSPQ was negatively but the EL was positively correlated with the mRNA expression of ghrelin and GHS-R (P < 0.01).
  
  
  CONCLUSIONS
  The CRF-caused changes of ghrelin system in hippocampus might be correlated with the CRF-caused cognitive function impairment.
authors: Department of Nephrology, Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, 710004, Shaanxi Province, People's Republic of China.
authors: Zhian
authors: Z
authors: Lv
authors: Department of Nephrology, Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, 710004, Shaanxi Province, People's Republic of China.
authors: Jie
authors: J
authors: Gao
authors: Department of Nephrology, Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, 710004, Shaanxi Province, People's Republic of China.
authors: Li
authors: L
authors: Wang
authors: Department of Nephrology, Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, 710004, Shaanxi Province, People's Republic of China.
authors: Zhao
authors: Z
authors: Chen
authors: Department of Anesthesia, Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, 710004, Shaanxi Province, People's Republic of China.
authors: Haozheng
authors: H
authors: Yuan
authors: Department of Nephrology, Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, 710004, Shaanxi Province, People's Republic of China.
authors: Xiaoqin
authors: X
authors: Ma
authors: Department of Nephrology, Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, 710004, Shaanxi Province, People's Republic of China.
authors: Jiamei
authors: J
authors: Lu
authors: Department of Anesthesia, Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, 710004, Shaanxi Province, People's Republic of China.
authors: Jianrui
authors: J
authors: Lv
authors: Department of Integrated Chinese Traditional and Western Medicine, Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, 710004, Shaanxi Province, People's Republic of China.
authors: Xili
authors: X
authors: Wu
authors: Medical Laboratory, Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, 710004, Shaanxi Province, People's Republic of China.
authors: Lei
authors: L
authors: Zhang
authors: Department of Nephrology, Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, 710004, Shaanxi Province, People's Republic of China.
authors: Linting
authors: L
authors: Wei
authors: Department of Anesthesia, Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, 710004, Shaanxi Province, People's Republic of China.
authors: Rongliang
authors: R
authors: Xue
authors: Department of Nephrology, Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, 710004, Shaanxi Province, People's Republic of China. pipifu@126.com.
authors: Rongguo
authors: R
authors: Fu
authors: Department of Nephrology, Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, 710004, Shaanxi Province, People's Republic of China. maliqun-doctor@tom.com.
authors: Liqun
authors: L
authors: Ma
mesh_terms: D000818:Animals; D060825:Cognitive Dysfunction / Q000209:etiology / Q000378:metabolism*; D054439:Ghrelin / Q000235:genetics / Q000378:metabolism*; D006624:Hippocampus / Q000378:metabolism*; D007676:Kidney Failure, Chronic / Q000150:complications*; D008297:Male; D012333:RNA, Messenger / Q000378:metabolism; D017207:Rats, Sprague-Dawley; D054440:Receptors, Ghrelin / Q000235:genetics / Q000378:metabolism*; D065854:Spatial Navigation; D014511:Uremia / Q000150:complications / Q000378:metabolism*
chemical_list: D054439:Ghrelin; D012333:RNA, Messenger; D054440:Receptors, Ghrelin
keywords: Chronic renal failure; Ghrelin; Hippocampus; Spatial cognitive function impairment