咽喉頭の嚥下誘発神経に関する研究  [in Japanese] Sensory nerves for initiation of reflex swallowing from the pharynx and larynx  [in Japanese]

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Abstract

咽頭・喉頭領域の機械刺激および喉頭領域を神経支配している上喉頭神経の電気刺激は, 嚥下誘発に有効である.しかしながら咽頭領域を神経支配している舌咽神経の電気刺激は, 上喉頭神経に比べ嚥下誘発が困難であるといわれている.このことは嚥下に関するパラドックスと呼ばれており, 未だに解決していない.今回の研究の目的は, このパラドックスを解明することである.<BR>咽頭・喉頭領域の嚥下誘発部位および神経支配を調べたところ, 機械刺激による嚥下誘発の高感受性部位は, 口蓋咽頭弓, 軟口蓋の後縁, 喉頭蓋の咽頭側外縁, 披裂喉頭蓋ヒダなどであり, これらの部位のうち, 口蓋咽頭弓, 軟口蓋の後縁は, 舌咽神経咽頭枝の切断の後, 嚥下誘発がなくなることから, 舌咽神経咽頭枝支配であることが判った.電気生理学的実験の結果は, 舌咽神経咽頭枝の電気刺激は, 上喉頭神経の電気刺激と同程度の嚥下誘発効果であったが, 舌咽神経舌枝の電気刺激は嚥下誘発に効果がなかった.また, 舌咽神経咽頭枝と上喉頭神経の同時刺激は嚥下誘発の促通を生じ, 舌咽神経舌枝と上喉頭神経の同時電気刺激は嚥下誘発を抑制した.これらの結果より, 舌咽神経のうち咽頭枝が嚥下誘発に重要な役割を果たしており, 舌枝は嚥下誘発に重要でないことが判った.パラドックスが生じた理由として, 過去の研究では舌咽神経舌枝のみ, あるいは舌咽神経舌枝と咽頭枝を同時に刺激していたのではないかと考えられる.

It is well known that mechanical stimulation of the pharyngeal areas innervated by the glossopharyngeal nerve (GPN) or the laryngeal areas innervated by the superior laryngeal nerve (SLN) readily elicits reflex swallowing. However, electrical stimulation of the SLN elicits reflex swallowing more readily than does stimulation of the GPN. This paradox remains unexplained; hence, the purpose of this study was to solve it.<BR>Mechanical stimulation with light pressure easily elicited reflex swallowing from the pharynx in the rat. The most effective reflexogenic regions were the palatopharyngeal arch, the edge of the pharyngeal surface of the epiglottis, the soft palate (extending region of the palatopharyngeal arch) and the aryepiglottic fold. Sectioning the pharyngeal branch of the GPN (GPN-ph) abolished the reflex swallowing from the palatopharyngeal arch and the soft palate out of these regions. The relationship between the frequency of electrical stimulation and the latency of swallowing for the GPN-ph was quite similar to that for the SLN. Electrical stimulation of the lingual branch of the GPN (GPN-li) was not effective in elicitation of swallowing. When electrical stimulation was applied simultaneously to both the GPN-ph and SLN, the latency of swallowing became shorter as compared with those for stimulation of each nerve. On the contrary, when electrical stimulation of the GPN-li was applied in addition to the stimulation of the SLN, reflex swallowing was delayed or inhibited.<BR>These results indicate that the GPN-ph plays a major role in initiation of reflex swallowing from the pharynx and that the electrophysiological properties of the GPN-ph for initiating swallowing are almost the same as those of the SLN, whereas the GPN-li plays a minor role and contains the inhibitory fibers for initiation of swallowing. Our findings provide a solution for the paradox regarding the initiation of swallowing.

Journal

  • The Journal of Japanese Society of Stomatognathic Function

    The Journal of Japanese Society of Stomatognathic Function 7(1), 47-52, 2001-01-31

    Japanese Society of Stomatognathic Function

References:  13

Cited by:  2

Codes

  • NII Article ID (NAID)
    110001091991
  • NII NACSIS-CAT ID (NCID)
    AN1047134X
  • Text Lang
    JPN
  • Article Type
    Journal Article
  • ISSN
    13409085
  • Data Source
    CJP  CJPref  NII-ELS  IR  J-STAGE 
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