| Project/Area Number |
17591647
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Anesthesiology/Resuscitation studies
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| Research Institution | Yokohama City University |
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Principal Investigator |
KIKUCHI Tatsuaki Yokohama City University, University Hospital, Associate Professor, 附属病院, 準教授 (70285138)
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| Co-Investigator(Kenkyū-buntansha) |
INAGAWA Gaku Yokohama City University, School of Medicine, Lecturer, 医学部, 助手 (60336584)
安藤 富男 山梨大学, 大学院・医学工学工学総合研究部, 教授 (00193110)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2006: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2005: ¥2,700,000 (Direct Cost: ¥2,700,000)
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| Keywords | acetylcholine / hippocampus / circadian rhythm / microdialysis / イソフルラン / 海馬 |
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| Research Abstract |
Background : Hippocampal acetylcholine (ACh) release, accepted as being responsible for cognition, learning and memory functions displays a circadian rhythm in rats, i.e. increases during the dark (active) phase, and decreases during the light (inactive) phase. The aim of the present experiment was to investigate the effect of isoflurane anesthesia on the circadian rhythm of hippocampal extracellular ACh level in rats using microdialysis technique, and compare this effect of isoflurane anesthesia administered during the light phase and that during the dark phase.
Methods : Young male rats were used in microdialysis studies. The dialysate was collected from the dorsal hippocampus at 20-min intervals under freely moving conditions for more than 60 h. Acetylcholine in the dialysate was measured by high performance liquid chromatography. The young male rats were divided into three groups (n=6 in each group) : Group Control : isoflurane anesthesia was not administered ; Group DA : 1.4% isoflurane was administered during dark (active) phase ; Group LA : 1.4% isoflurane was administered during light (rest) phase. In vivo microdialysis studies were performed in free moving conditions. The dialysate was collected from the dorsal hippocampus at 20-min intervals for more than 60 h. Acetylcholine in the dialysate was measured by high performance liquid chromatography.
Results : The hippocampal acetylcholine release showed clear diurnal change in Group Control. In Group DA, the diurnal change of ACh release was significantly disrupted after isoflurane anesthesia, while isoflurane anesthesia coused no effect in Group LA.
Conclusions : The influence of isoflurane anesthesia on the hippocampal ACh circadian rhythm was pronounced when administered during the active phase than that administered during the rest phase. Our finding suggested that anesthesia during different phase might cause different effect on circadian rhythm.
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