title: Low pH of interstitial fluid around hippocampus of the brain in diabetic OLETF rats.
abstract: BACKGROUND
  We have reported that pH values of ascites and interstitial fluids around the liver in Otsuka Long-Evans Tokushima Fatty (OLETF) rats are significantly lower than normal pH, 7.40, of mammalian body fluids (Biochem Biophys Res Commun 2013, 432:650), and that this lowered pH of interstitial fluid causes the insulin resistance in diabetic patients by decreasing insulin-binding to its receptors (J Physiol Sci 2013, 63:S199). In the preset study, we tried to measure the interstitial fluid pH in diabetic OLETF rats, since the interstitial fluid pH plays key factors in the brain function from a viewpoint of the binding affinity of neurotransmitters to their receptors.
  
  
  RESULTS
  We found that the pH value of interstitial fluids around hippocampus, the most important area for memory, in diabetic OLETF rats was lower than that in normal rats by measuring pH with antimony pH electrodes.
  
  
  CONCLUSIONS
  The lowered pH of interstitial fluid around hippocampus of the brain in diabetic rats observed in the present study suggests that the function of hippocampus of the brain would be diminished due to low affinity of various types of neurotransmitters, playing key roles in the hippocampus function, to their receptors. Therefore, we indicate that maintenance of the interstitial fluid pH at the normal level would be one of the most important key factors for molecular and cellular therapies in various types of diseases including diabetes mellitus.
authors.affiliation: Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, 602-8566 Japan ; Department of Bio-Ionomics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, 602-8566 Japan ; Japan Institute for Food Education and Health, St. Agnes' University, Kyoto, 602-8013 Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Marunaka
authors.affiliation: Department of Forensic Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, 602-8566 Japan ; Departments of Food Sciences and Biotechnology, and Health, Faculty of Life Sciences, Hiroshima Institute of Technology, Hiroshima, 731-5193 Japan.
authors.forename: Kanji
authors.initials: K
authors.lastname: Yoshimoto
authors.affiliation: Laboratory of Health Science, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, 606-8522 Japan.
authors.forename: Wataru
authors.initials: W
authors.lastname: Aoi
authors.affiliation: Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, 602-8566 Japan ; Japan Institute for Food Education and Health, St. Agnes' University, Kyoto, 602-8013 Japan.
authors.forename: Shigekuni
authors.initials: S
authors.lastname: Hosogi
authors.affiliation: Department of Forensic Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, 602-8566 Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ikegaya
keywords: Antimony pH electrode; Diabetes mellitus; Hippocampus; OLETF rat; pH