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2001 Fiscal Year Final Research Report Summary

Circadian Variation of GABAergic Action in the Supracgiasmatic Nucleus Neurons.

Research Project

Project/Area Number 12670056
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Environmental physiology (including Physical medicine and Nutritional physiology)
Research InstitutionHamamatsu University School of Medicine

Principal Investigator

SAMEJIMA Michikazu  Department of Physiology, Hamamatsu Univ Sch of Med, Associate Professor, 医学部, 助教授 (80135251)

Co-Investigator(Kenkyū-buntansha) OKABA Akihito  Department of Physiology, Hamamatsu Univ Sch of Med, Research Associate, 医学部, 助手 (10313941)
UCHIDA Katsuhisa  Department of Physiology, Hamamatsu Univ Sch of Med, Research Associate, 医学部, 助手 (10168693)
FUKUDA Atsuo  Department of Physiology, Hamamatsu Univ Sch of Med, Professor, 医学部, 教授 (50254272)
Project Period (FY) 2000 – 2001
KeywordsINTRACELLULAR Cl^- CONCENTRATION / SUPRACHIASMATIC NUCLEUS / INHIBITORY SYNAPTIC TRANSMISSION / Cl^-IMAGIN / MEQ / GABA
Research Abstract

In this project, change of intracellular Cl^- concentration was directly measured by imaging method. Cl^- sensitive fluorescent dye, MEQ (6-methoxy-N-ethylquinolinium iodide), was loaded to the rat brain slices. The neurons in rat suprachiasmatic nucleus showed blue fluorescence by excitation light of 355 nm. The fluorescence intensity was changed by the bath application of 100 um GABA. In some cases, the fluorescence change of MEQ indicated the increase of [Cl^-]_i, and in other cases, the decrease of [Cl^-]_i. To obtain the final result, it is necessary to measure many neurons. Second, we evaluated if the change in MEQ fluorescence actually indicated the change in [Cl^-]_i, because there was a question that MEQ fluorescence would also changed according to the cellular volume change accompanied with Cl^- or other ion influx and/or eflux. To answer this question, we loaded calcein to the slices so that we could measure the cell volume change simultaneously to [Cl^-]_i change. Calcein is insensitive to any intracellular ionic concentration change or pH change. It is sensitive only to cell volume change. The results indicates that pseudo-ratiometric measurement of [Cl^-]_i is feasible by taking the ratio of MEQ fluorescence change to calcein fluorescence change (F_<MEQ>/F_<calcein>). Finally, we improved the method to obtain the absolute intracellular Cl^- concentration by using MEQ fluorescence. In this case, extracellular Cl^- should be substituted by other anions to take the calibration curve to culculate [Cl^-]_i. For this purpose, the anion which least quenches the intracellular MEQ should be used. Metylsulfric acid potassium salt was found to be the best anion for this purpose.

  • Research Products

    (10 results)

All Other

All Publications (10 results)

  • [Publications] Yamada, Y. et al.: "Optical imaging reveals cation-Cl^-cotransporter-mediated transient rapid decrease in intracellular Cl^-concentration induced by oxygen-glucose deprivation in immature rat neocortical slices"Neuroscience Research. 39. 269-280 (2001)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Uchida, K. et al.: "Effects of cGMP and cAMP on light responses of the photosensory pineal neurons in the lamprey, Lampetra japonica"Biological Signals and Receptors. 10. 389-398 (2001)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 福田敦夫: "脳における細胞内Cl^-の調節と神経機能"脳の科学. 22. 219-223 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Samejima, M. et al.: "Light and temperature-dependence of the melatonin secretion rhythm in the pineal organ of the lamprey, Lampetra japonica"Jpn. J. Phyisiol.. 50. 437-442 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Yamada, Y. et al.: "Immature stage of intracellular Cl^-homeostasis regulated by cation-Cl^-cotransporters in rat neocortical neurons"Nagoya Medical Journal. 43. 179-190 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Yamada, Y. et al.: "Optical imaging reveals cation-Cl^- cotransporter-mediated transient rapid decrease in intracellular Cl concentration induced by oxygen-glucose deprivation ir immature rat neocortical slices"Neuroscience Research. 39. 269-280 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Uchida, K. et al: "Effects of cGMP and cAMP on light responses of the photosensory pineal neurons in the lamprey, Lampetrc, japonica"Biological Signals and Receptors. 10. 389-398 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Fukuda, A.: "Intracelullar Cl^- homeostasys and neural mechanism ir the brain"NOUNO KAGAKU. 22. 219-223 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Samejima, M. et al.: "Light- and temperature-dependence of the melatonir secretion rhythm in the pineal organ of the lamprey Lampetra japonica"Japanese Journal of Physiology. 50. 437-442 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Yamada, Y. et al.: "Immature stage of intracellular Cl^- homeostasis regulated by cation-Cl- cotransporters in rat neocortical neurons"Nagoya Medical Journal. 43. 179-190 (2000)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 2003-09-17  

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