| Project/Area Number |
60480112
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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 | Asahikawa Medical College |
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Principal Investigator |
MORI Shigemi Asahikawa Medical College, Professor, 医学部, 教授 (80001907)
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| Co-Investigator(Kenkyū-buntansha) |
ATSUTA Yuji Asahikawa Medical College, Instructor, 医学部, 助手 (90167924)
SUGAYA Kimio Asahikawa Medical College, Instructor, 医学部, 助手 (20179120)
OHTA Yoshihiro Asahikawa Medical College, Instructor, 医学部, 助手 (00142802)
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| Project Period (FY) |
1985 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥6,200,000 (Direct Cost: ¥6,200,000)
Fiscal Year 1986: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1985: ¥5,100,000 (Direct Cost: ¥5,100,000)
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| Keywords | Postural suppression / Nucleus reticularis pontis oralis / Nucleus reticularis Gigantocellularis / Carbachol / Focal injection / Spike-triggered averaging / Carbachol / 化学刺激 |
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| Research Abstract |
A ponto-medullary and spinal system, that is involved in postural suppression, has been identified by means of axonal flow techniques for both retro- and antero-grade tracing. It originated from cells in the nucleus reticularis pontis oralis (Po0) and the descending axons coursed through the dorsal portion of the caudal tegmental field (DTF) in the pons along its midline. They terminated on somata of cells in the nucleus reticularis gigantocellularis (Gc), and these cells projected their descending axons to the lumbar spinal cord. The cells in the nucleus Gc also projected their ascending axons to the nucleus Po0 suggesting an existence of "reverberating neuronal circuits" between the nucleus Po0 and the nucleus Gc. A single stimulation delivered to the DTF area activated antidromically cells in the nucleus Po0. Cells in the nucleus Gc were activated orthodromically by the same stimulation and were activated antidromically by stimulating the spinal cord. In reflexively standing decerebrate cats, focal injection of carbachol (long-acting cholinomimetic agent resistant to acethylcholinesterases) into the nucleus Po0 resulted in the suppression of extensor muscle tone in the hindlimbs. With this injection, cells both in the nucleus Po0 and the nucleus Gc started to fire tonically, and the membrane potential of alpha-motoneurons (MNs) innervating extensor muscles were hyperpolarized. The effects exerted upon alpha-MNs were quite similar to those induced upon them by a train pulse stimulation delivered to the DTF area. Averaging of intracellularly recorded membrane potentials of alpha-MNs, triggered by the extracellularly recorded action potentials of the cells in the nucleus Gc, revealed postsynaptic inhibitory potentials both in extensor and flexor alpha-MNs innervating hindlimbs. All these results clearly demonstrated that cells in the nucleus Po0 and those in the nucleus Gc play the roles of "trigger neurons" and "relay neuron", respectively, in postural suppression.
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