1989 Fiscal Year Final Research Report Summary
Morphological and physiological investigation of the neuromuscular junction in the recurrent laryngeal nerve palsy
| Project/Area Number |
62570781
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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 |
Otorhinolaryngology
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| Research Institution | Saga Medical School |
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Principal Investigator |
TAKEMOTO Shin Saga Medical School, Professor, 医学部, 教授 (70080869)
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| Co-Investigator(Kenkyū-buntansha) |
WADA Shigeru Saga Medical School, Instructor, 医学部, 助手 (50175147)
MORIKAWA Ikuro Saga Medical School, Lecture, 医学部, 講師 (60140696)
MAEYAMA Tadatsugu Saga Medical School, Lecture, 医学部, 講師 (20145189)
WATANABE Hiroshi Saga Medical School, Assistant Professor, 医学部, 助教授 (50109394)
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| Project Period (FY) |
1987 – 1989
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| Keywords | recurrent laryngeal nerve / misdirected reinnervation / freezing injury / neurorrhaphy / vocal fold / electromyogram / motoneuron / movement of vocal fold |
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| Research Abstract |
The purpose of this investigation was to clarify misdirected reinnervation after injury of the recurrent laryngeal nerve(RLN).
1. Degeneration and regeneration processes, and reorganization of the motoneurons reinnervating the posterior cricoarytenoid muscle(PCA) after freezing injury of the unilateral RLN of the guinea-pig were observed. Most axons degenerated within 3 days and regenerative sprouting with growth cones was observed after 7 days. From between 2 to 6 months, the number of the motoneuron in the PCA gradually increased and the area occupied by regenerated neurons gradually expanded. Regenerated PCA motoneurons were found outside the PCA motoneuron area of the control. Target specific regeneration was incomplete even after freezing injury in which neurites were damaged but the basal lamina was not affected.
2. The movement of the vocal fold, electromyogram of the internal laryngeal muscles and reorganization of the PCA motoneurons were observed after neurorrhaphy or freezing injury of the unilateral RLN of the cat. In neurorrhaphy cases, the vocal fold on the damaged side was fixed in the paramedian position and the activity pattern of the vocalis muscle and PCA differed from those of the normal side even after 9 months. Many regenerated PCA motoneurons existed outside the PCA motoneuron area of the control. These results suggested that the dysfunction of the vocal fold in the affected side was caused by misdirected reinnervation in the internal laryngeal muscles. In freezing injury cases, movement of the vocal fold and electromyogram returned to normal after 4 months, and a few regenerated motoneurons were found outside the normal PCA motoneuron area. It is suggested that the functions of the internal laryngeal muscles were practically normal, although a slightly misdirected reinnervation occurred.
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Research Products
(6 results)
