大鼠氣道負壓對上呼吸道運動神經活動之影響

蔡欣曄

指導教授 ： 蔡欣曄

國立臺灣師範大學/理學院/生命科學研究所/碩士(2007年)

摘要

本實驗以Wistar品系大白鼠為材料，動物經麻醉後，進行氣管與股動靜脈插管，以gallamine triethiodide麻痺，接人工呼吸器。分離膈神經，舌下神經、喉返神經以及喉返神經內收支與外展支。將人工呼吸器的呼氣端，藉由PE管安置於水面下3公分，使呼氣末壓力（positive end-expired pressure; PEEP）為 3 cmH2O作為對照，實驗時，以所測氣管壓力代表氣道壓力變化，將氣道壓力從對照降低到PEEP= 0 cmH2O，再進一步降低到連續氣道負壓（continuous negative airway pressure; CNAP）或呼氣末負壓（negative end-expired pressure; NEEP）為 -1與 -3 cmH2O，然後，升高氣道壓力為PEEP= 6 cmH2O，研究這些不同氣道壓力（6、0、-1、-3 cmH2O）對喉返神經與舌下神經活動的影響。結果顯示，氣道負壓會引起血壓升高，呼吸頻率加快，膈神經立即反應沒有明顯變化，喉返神經內收支活動增強、活動時間延長，因而轉變為連續性活動，相對地，喉返神經外展支活動高度沒有明顯變化，但是活動開始時間延後，這種反應雖然與興奮C纖維所引起的反應相似但卻無關，舌下神經活動高度降低，且活動開始時間延後。PEEP等於 6 cmH2O時，血壓降低，呼吸頻率降低，膈神經立即反應也是沒有明顯變化，喉返神經內收支與外展支活動降低，舌下神經活動高度無明顯改變，僅活動開始時間提前。喉返神經內收支與舌下神經活動的反應，可能是增強上呼吸道的阻力，以留住肺裡的氣體，顯示可能與防禦機制以維持肺體積的大小有關。

關鍵字

氣道負壓 ； 喉返神經 ； 舌下神經 ； 肺體積 ； 反射 ； 快適應接受器

並列摘要

To study the effect of changes in airway pressure on upper airway motor nerve activities, adult rats of Wistar were used. The rat was anesthetized with urethane, paralyzed, and artificially ventilated. Catheterization was performed in the trachea, femoral artery and vein. The phrenic, recurrent laryngeal (RLN), and hypoglossal nerves, as well as the abducent (Abd) and adducent (Add) branches of the RLN were separated and their activities were recorded under normocapnia in hyperoxia. The outlet of the ventilator was placed under water surface with a deep of 3 cm such that a 3-cmH2O positive end-expired pressure (PEEP) was obtained to be used as the control. The airway pressure measured by the tracheal pressure (TP) was decreased to a level of continuous negative airway pressure (CNAP) and of negative end-expired pressure (NEEP) at -1 and -3 cmH2O with a water trap system, and then increased to PEEP at 6 cmH2O. The observed results showed that blood pressure and respiratory frequency were increased, and phrenic burst was not changed in immediate response to CNAP and PEEP, and that activity of the entire RLN was significantly increased during inspiratory and expiratory period. Data from the recording of the intralaryngeal branches showed that activity of the Add RLN was increased and also extended to the inspiratory duration such that it transformed into a tonic discharge pattern with CNAP and NEEP. Activity of the hypoglossal nerve was significantly and immediately decreased with CNAP and NEEP. Increase in PEEP at 6 cmH2O produced a decrease of blood pressure and respiratory frequency without conspicuous change in phrenic burst. Activity of the Add RLN and Abd RLN was decreased. There was no change in hypoglossal activity but displayed an advancement in onset. All these reflexive responses were totally abolished after bilateral vagotomy. These results showed that airway resistance may be increased due to the increase of activity of the Add RLN and the decrease of hypoglossal discharge and that this increase in airway resistance may benefit for the maintenance of lung volume.

並列關鍵字

negative airway pressure ； recurrent laryngeal nerve ； hypoglossal nerve ； lung volume ； reflex ； rapidly adapting receptors

參考文獻

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