喉頭からの知覚衝撃とその発生機構

緒言

　さきに^11），著者は上喉頭神経単一線維における自発性知覚衝撃を記録し，とくにこれらの衝撃の放射が呼吸の律動と如何なる関係をもつているかという点について詳細に検討し各種の典型に類別した。

　それによると，ramus internusの衝撃は呼吸律動に同調してその頻数を変えるもの，およびこれと全く無関係のものに大別される。前者はさらに呼吸のphaseとの関係から多くの小典型が区別される。また，ramus externusにおいては呼息末期から呼吸間歇期にかけて頻数増加をしめす衝撃典型が証明されることから，本神経枝がM．cricothyreoideusに対する純運動神経であると見做していた従来の見解の誤りを指摘した。しかしこの論文においては上述した各衝撃群が如何なる機構によつて生起されるかについては明かにされていない。

　With the indication of unitary afferent spike discharges of the superior laryngeal nerve fibers, the location and the mechanism of their generation have been studied in adult cats. The courses and the results are summarized just as follows.

　1. A group of laryngeal afferent fiber units in the ramus internus changes their discha-rge frequency of impulses corresponding with the respiratory rhythm. These units are classified into two subgroups whether their impulses are ceased to discharge or not when the passage of respiratory air through the larynx is completely interrupted.

　2. The units belonging to the former group exhibit a remarkable discharge of impulses when the laryngeal mucous membrane is stimulated mechanically with air stream as well as touching-hair. On the other hand, those of the latter respond when the thyreoepiglottic joint and the aryepiglottic muscle are stretched by pulling the apex of the epiglottis ven-tro-caudally.

　3. In the units of the former the impulses produced spontaneously and those evoked by mechanical stimulation rapidly decrease their number when 4% solution of xylocaine is sprayed over the surface of laryngeal mucous membrane. On the contrary, there observed no change in the course of discharge of the units belonging to the latter group by applica-tion of xylocaine solution.

　4. Histologicaliy, the presence of nerve endings resembled to Meissner's corpuscles or so-called genital corpuscles have been confirmed in the epithelial layer of laryngeal mucosa situated orally to the glottis.

　5. From these experimental results, it may be concluded that the impulses observed in the former group of nerve fibers originated in the mucosal touch receptors above described, and those in the latter in the proprioceptors in the thyreoepiglottic joint, being already reported by Andrew, as well as in in the aryepiglottic muscle.

　6. The unitary laryngeal afferent impulses in the ramus externus exhibit the increaseof their number, being slowly adapting, when the cricothyroid muscle is excessively stre-tched from its normal position. The origin of impulses above described may be conseque-ntly ascribed to the proprioceptors in the muscle.