| Project/Area Number |
01480120
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Neurophysiology and muscle physiology
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| Research Institution | Tokyo Medical and Dental University |
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Principal Investigator |
KAMINO Kohtaro Tokyo Medical and Dental University, School of Medicine, Professor., 医学部, 教授 (40025630)
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| Co-Investigator(Kenkyū-buntansha) |
KOMURO Hitoshi Tokyo Medical and Dental University, School of Medicine, Instructor., 医学部, 助手 (40195863)
SAKAI Tetsuro Tokyo Medical and Dental University, School of Medicine, Lecturer., 医学部, 講師 (40153845)
HIROTA Akihiko Tokyo Medical and Dental University, School of Medicine, Assistant Professor., 医学部, 助教授 (50156717)
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| Project Period (FY) |
1989 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥7,600,000 (Direct Cost: ¥7,600,000)
Fiscal Year 1991: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1990: ¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 1989: ¥3,700,000 (Direct Cost: ¥3,700,000)
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| Keywords | voltage-sensitive dye / optical recording / embryonic brain stem / functional organization / vagus nerve / neural activity / glutaminergic EPSP / mapping / ダルタミン酸 / メロシアニンロ-ダニン |
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| Research Abstract |
In intact and slice preparations of the vagus/brain stem isolated from 3-to 8-day old chick embryos, the spatial pattern of neural responses to vagal stimulation and its development were assessed by using multiple-site optical recording of electrical activity, with a voltage-sensitive merocyanine-rhodanine dye (NK2761) and a 12 x 12-element photodiode array. Voltage-related optical (absorbance) changes evoked by vagus nerve stimulation with depolarizing (positive) square current pulses using a suction electrode were recorded simultaneously from 127 contiguous loci in the preparation. The measurements were made by successive displacements of the photodiode array over the image of the preparation.
The first neural responses, viz., fast optical signals related to the action potentials were recorded in the 4-day old brain stem preparations, and the slow optical signals were detected from late 7- and 8-day old brain stem preparations. The size of the slow signal was decreased by continuous s
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timulation, reduced by low external calcium ion concentrations and eliminated in the presence of manganese or cadmium ion. The slow signals were eliminated in the presence of kynurenic acid, and they were reduced by 2-APV (DL-2-amino-5-phosphono-valeric acid) and by CNQX (6-cyano-7nitroquinoxaline-2, 3-dione). We concluded that the slow signals correspond to excitatory postsynaptic potentials which are glutamate-mediated.
The evoked optical signals appeared to be concentrated longitudinally in the central region on the stimulated side of the intact brain stem preparations and in a limited dorsal area in the slice preparations. The signal size gradually increased and the response area expanded as development proceeded. Based on the above results, we have constructed developmental maps of spatial patterns of the fast and slow responses. In the maps, the positions of the peak-size area of the fast and slow signals were assessed, and we have found that there were differences in the relative locations of the peak-size regions between the fast and slow signals in the late 7- and 8-day old embryonic brain stem preparations. The fast signal response area seems to correspond to the dorsal motor nucleus of the vagus nerve and the slow signal response area to the nucleus tractus solitarii. Less
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