2000 Fiscal Year Final Research Report Summary
Plasticity of Respiration and Central Nervous System after Spinal Hemisection
| Project/Area Number |
11835028
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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 Institution | Ibaraki Prefectural University of Health Sciences |
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Principal Investigator |
SASAKI Sei-ichi Ibaraki Prefectural University of Health Sciences, Center for Medical Sciences, Professor, 保健医療学部, 教授 (50153987)
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| Co-Investigator(Kenkyū-buntansha) |
NIWA Masatoshi Department of Occupational Therapy, Instructor, 保健医療学部, 講師 (90274985)
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| Project Period (FY) |
1999 – 2000
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| Keywords | Spinal cord / Plasticity / Phrenic nerve / Respiration / Motoneuron / Spinal hemisection |
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| Research Abstract |
In the present study, a recovery of phrenic nerve activities after the cervical hemisection of the spinal cord was examined. Experiments were performed on anesthetized cats. Spinal segments were exposed at C3-C4. Spinal cord was hemisected at the junction of C3/C4. All surgery was done using aseptic techniques. The phrenic nerve discharges of the hemisected side were recorded 3 months after the hemisection and compared with that of the intact side. The phrenic nerve of the hemisected side have shown the functional recovery of inspiratory activities, although inspiratory activities were weaker than that of the intact side. When end-expiratory CO2 level was increased by adjusting ventilator, the phrenic nerve discharges of both side increased. Intracellular recording was made in order to elucidate respiratory synaptic events in phrenic motoneurons after spinal hemisection. Experiments were performed on anesthetized cats. The microelectrode for intracellular recording from phrenic motoneurons was filled with 3 M KCl solution. The excitatory postsynaptic potential (EPSP) is produced in the phrenic motoneurons at inspiratory phase and the inhibitory postsynaptic potentials (IPSP) at expiratory phase. This study led to the conclusion that the respiratory activities of phrenic nerves are attributable not only a recovery of excitatory neural circuit, but also a recovery of inhibitory nerual circuit to the phrenic motoneurons.
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