2006 Fiscal Year Final Research Report Summary
Study for stress-induced morphological alterations of neural dendrites in Fisher344 rats, an animal model for stress-vulnerability
| Project/Area Number |
17591215
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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 |
Psychiatric science
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| Research Institution | Yamaguchi University |
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Principal Investigator |
WATANABE Yoshifumi Yamaguchi University, Graduate School of Medicine, Professor, 大学院医学系研究科, 教授 (90182964)
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| Co-Investigator(Kenkyū-buntansha) |
NISHIDA Akira Yamaguchi University, Hospital, Assistant Professor, 医学部附属病院, 講師 (20372708)
SUETSUGI Masatomo Yamaguchi University, Hospital, Assistant Professor, 医学部附属病院, 講師 (40294631)
UCHIDA Shusaku Yamaguchi University, Graduate School of Medicine, Research Associate, 大学院医学系研究科, 助手 (10403669)
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| Project Period (FY) |
2005 – 2006
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| Keywords | stress-vulnerability / neural plasticity / animal model for depression / spine / neural dendrite / hippocampus / amygdala |
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| Research Abstract |
Early studies have reported that chronic severe stress induced dendritic atrophy and neural loss of CA3 pyramidal neurons in the hippocampus. It is hypothesized that mood disorder patients would have the genetically determined vulnerability to stress and aberrant neural plasticity. It is considered that the stress-induced neural damages in the hippocampus described above would occur during a depressive state leading to loss of hippoccampal volume in mood disorders. Our question regarding to this hypothesis is whether Fisher 344 rats, an animal model with the vulnerability to chronic stress for mood disorders, will show morphological alterations of hippoccampal pyramidal neurons by weak chronic stress. Fisher 344 rats were subjected to 6 hours restraint stress daily for 7 or 14 consecutive days, since Sprague-Dawley rats were reported to show the dendritic atrophy of CA3 neurons by 6 hours restraint stress for 21 days, but not for 14 days. Fisher 344 rats were deeply anesthetized and perfused 24 hours after the last restraint stress. Blocks of tissue containing the hippocampus or amygdala were dissected and processed for Golgi impregnation technique. Dendritic length, branch point numbers, and spine density of CA1, CA3 pyramidal neurons in the hippocampus, and spine density of pyramidal and stellate neurons in the basolateral nucleus of amygdala were determined. 7 day-and 14 day-restraint stress did not show any effects on the parameters of dendritic morphology in both CA1 and CA3 pyramidal neurons. However, 14 days-restraint stress decreased the spine density of the stellate neurons in the basolateral nucleus of the amygdala.
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