カエル舌咽神経の再生後の形態的、機能的変化に関する研究

概要

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The purpose of the present study is to investigate morphologically and physiologically the connection through collateral branches between fungiform papillae, conduction velocities and diameters of fibers in regenerated glossopharyngeal nerve. The experiments were carried out with bullfrogs (Rana catesbiana) at room temperature, about 25℃. First, glossopharyngeal nerve of the left side was cut off at proximal portion in maxilla. These frogs were raised from 212 to 452 days after operation. In this period, the connection by collateral branches between a fungiform papilla and other papillae was investigated with suction electrode sucking a papilla (Rapuzzi, 1956). Conduction velocities, numbers and diameters of fibers including in regenerated nerves were measured with several preparations after 212 to 452 days of operation. Conduction velocities of several fibers in regenerated nerve were measured by recording impulses conducted most early to papillae after stimulus to nerve trunk. Number of myelinated fibers in regenerated nerve was counted with many micrographs of crossed section of this nerve in the vicinity of tongue. Areas, circumferences, diameters and shape factor (indicate circle or not) of myelinated fibers in the same trunk were measured at inside of myelin sheath with a microcomputor-based system for morphometric analysis to many electron micrographs enlarged (magnification : 660 or 1000). The controls of these experiments were employed intact glossopharyngeal nerves in the right sides. The main findings were summerized as follows. 1. In control preparations of 35 cases, number of connected fungiform papillae which generated action potentials after stimulus to a fungiform papilla was from 10 to 46 (mean 22.6). Connected papillae were almost in the neighborhood of a stimulated papilla. 2. After cutting of nerve, impulses of collateral fibers connected between some papillae were disappeared. After 1 or 2 months of operation, small impulses generated in small number of papillae by stimulus of a papilla. These impulses increased in amplitude and frequency with the lapse of time, and number of papillae connected with collateral branches increased also, but in almost preparation at 212 to 452 days after operation, both amplitude, frequency of impulse and number of connected papillae did not return to those of control nerve. The connected papillae after regeneration were in area existed them before operation. 3. In 5 of 6 cases, conduction velocities of regenerated fibers were smaller than those of intact nerve. 4. In 5 of 6 cases, number of myelinated fibers in regenerated nerve was smaller than that of intact one. 5. In all 5 cases, areas, circumferences and diameters of regenerated fibers were smaller than those fo intact ones and these values of 4 cases were recognized significant difference (α=0.01). Shape factors did not indicate definite correlation.
九州歯科学会の論文
1983-02-25

著者

友松俊之
九州歯科大学口腔治療学教室

カエル舌咽神経の再生後の形態的、機能的変化に関する研究

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