| Project/Area Number |
03650289
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
情報工学
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| Research Institution | Akita University |
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Principal Investigator |
TAKIMORI Tohru Akita University Mining College, Department of Information Engineering, Lecturers, 鉱山学部, 講師 (50006730)
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| Co-Investigator(Kenkyū-buntansha) |
OGAWA Tetsuro Akita University School of Medicine, Department of First Physiology, Professor, 医学部, 教授 (80004555)
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| Project Period (FY) |
1991 – 1992
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| Project Status |
Completed (Fiscal Year 1992)
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| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1992: ¥200,000 (Direct Cost: ¥200,000)
Fiscal Year 1991: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | Cat Visual Cortex / Excitatory Amino Acids / NMDA Receptors / Layer 5 Neurons / 視覚野 / MNDA / 5層ニュ-ロン |
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| Research Abstract |
We studied electropysiological and pharmachological properties of EPSP evoked in layer 5 neurons by electrical stimulation of layer 2/3 in vitro slices of kitten (2-3M old) visual cortex. The EPSP showed the following properties.
1) The mean latency of the EPSP was 3.4msec and latencies to different stimulus intensities remained same.
2) It consisted of two components ; the fast one showed a rapidly rising phase and the slow one a slowly rising phase. The fast component was abolished by bath application of CNQX(10-20muM), a selective antagonist of non-NMDA receptors, but was unaffected by bath application of APV (50muM), a specific antagonist of NMDA receptors. In contrast, the slow component was not affected by CNQX, but depressed by APV. In Mg^<++> free medium only the slow component was augmented in size and prolonged in duration but this was blocked by APV.
3) In a low Ca^<++>- high Mg^<++> bathing medium which blocked synaptic transmission, the layer 5 neurons were strongly depolarized by iontophoresis of NMDA. This effect was blocked by APV.
4) Using a single electrode voltage-clamp method, the slow EPSC was recorded in the medium containing CNQX, the amplitude of which increased with a deporalization of the membrane potential.
5) Pressure injection of Cd^<++>ion to the vicinity of the cell body abolished both the fast and slow components simultanously.
6) The effective site of electrical stimulation for the fast component was within 250mum directly over the layer 5 cells and for the slow component it extended over 750mum.
These results suggest that the afferent inputs from 2/3 layer to layer 5 neurons were monosynaptically transmitted via both non-NMDA receptors and NMDA receptors located at proximal dendrites or the soma and that the inputs responsible for the slow component of EPSP were distributed over wider region in layer 2/3 than those for the fast component.
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