2000 Fiscal Year Final Research Report Summary
Analysis of mechanisms of pheromonal memory formation
| Project/Area Number |
10460133
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Basic veterinary science/Basic zootechnical science
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| Research Institution | Kochi Medical School |
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Principal Investigator |
KABA Hideto Kochi Medical School, Faculty of Medicine, Professor, 医学部, 教授 (50136371)
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| Co-Investigator(Kenkyū-buntansha) |
TANIGUCHI Mutsuo Kochi Medical School, Faculty of Medicine, Instructor, 医学部, 助手 (10304677)
OKUTANI Fumino Kochi Medical School, Faculty of Medicine, Instructor, 医学部, 助手 (10194490)
TAKAHASHI Seiichi Kochi Medical School, Faculty of Medicine, Associate Professor, 医学部, 助教授 (40271093)
MORI Yuji University of Tokyo, Faculty of Agriculture, Professor, 農学部, 教授 (40157871)
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| Project Period (FY) |
1998 – 2000
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| Keywords | pheromonal memory / accessory olfactory bulb / primary culture / slice / glutamate receptor / noradrenaline / vaginal stimulation / glia |
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| Research Abstract |
When female mice were mated, they form an olfactory memory to the pheromones of the mating male. The neural changes underlying this memory occur in the accessory olfactory bulb (AOB), depend upon mating-induced release of noradrenaline (NA) in the AOB and involve changes at the reciprocal synapses between mitral and granule cells. In this study we have obtained the following results.
1. In situ hybridization experiments suggest that there is a pheromone-specific activation of neuronal nitric oxide synthase mRNA in the AOB during memory formation which may regulate intermediate synaptic processes.
2. Using slices of the mouse AOB, we demonstrated opposite roles for N-methyl-D-aspartate receptors and group II metabotropic glutamate receptors in the dendrodendritic feedback inhibition of AOB mitral cells.
3. In vivo electrophysiological experiments showed that vaginocervical stimulation enhances the activity of AOB mitral cells through a reduction in reciprocal dendrodendritic inhibition.
4. Behavioural and immunohistochemical analyses demonstrated an important role for glial cells in the formation of pheromonal memory. In addition, we showed immunohistochemical expression patterns of glutamine synthetase and microglia-specific ionized calcium binding adaptor protein (Iba 1) in the mouse olfactory bulb.
5. As a further step in exploring the detailed mechanisms underlying the pheromonal memory, we have simplified the analysis of neuronal circuit by reconstituting the dendrodendritic synapse between mitral and granule cells in primary dissociated cultures of AOB neurons. Using this in vitro system, we demonstrated that NA reduces GABAergic inhibitory postsynaptic currents in mitral cells by a presynaptic mechanism.
6. In vivo and in vitro electrophysiological experiments demonstrated modulatory actions of the neurosteroid dehydroepiandrosterone and oxytocin on synaptic transmission between mitral and granule cells in the olfactory bulb.
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