本研究目的在探討大白鼠延腦背側 (dorsal medulla﹔DM) 升壓區對顏面神經呼吸活動的影響。大白鼠以戊巴比妥鈉 (sodium pentobarbital; 35 mg/kg， i.p) 麻醉，切斷兩側迷走神經，以肌肉痲痹劑 (gallamine triethiodide；5 mg/kg，i.v.) 痲痹大白鼠後，進行氣管切開術，接上人工呼吸器，呼氣末二氧化碳濃度維持 0.04。在高氧二氧化碳濃度正常和高氧二氧化碳濃度增加下，微量注射麩胺酸鈉 (50 mM，20-30 nl) 到DM 以興奮這裡的神經細胞，觀察膈神經和顏面神經呼吸活動的反應。 注射 1.0 nmole 和1.5 nmole劑量的麩胺酸鈉興奮 DM 升壓區的神經細胞﹐對膈神經和顏面神經所引起的呼吸活動的影響可分為兩種類型︰第一類型反應(typeⅠ)，膈神經和顏面神經吸氣活動均降低，使得平均膈神經活動高度分別降低為刺激前 (對照組) 的百分之 79.49 ± 2.09 (降幅達20.51%，p < 0.05) 和76.53 ±3.31 (降幅達23.47%，p < 0.05) ﹐平均顏面神經吸氣活動高度分別降低為刺激前的百分之63.53±4.14 (降幅達36.47％﹐p < 0.05) 和69.38±3.96(降幅達30.62％﹐p < 0.05) 。 第二類型反應 (typeⅡ），膈神經活動不受影響，但顏面神經吸氣活動降低，平均顏面神經吸氣活動高度分別降低為刺激前的百分之72.08±4.14 (降幅達27.92％﹐p < 0.05) 和63.33 ± 7.55 (降幅達36.67％﹐p < 0.05) ﹐不論是第一類型反應或第二類型反應﹐顏面神經的呼氣活動都會因DM神經細胞被興奮而增強。這些結果暗示DM升壓區可藉著影響顏面神經的呼吸活動，而能進一步調控上呼吸道的通暢。

The aim of the present study was to examine respiratory-modulatedfacial nerve activity (Fac) in response to activation of the dorsalmedulla (DM) in rats. The animal was anesthetized with sodium pento-barbital (35 mg/kg, i.p.) and then vagotomized bilaterally, paralyzedand ventilated artificially. End-tidal fractional concentration of CO2was maintained at normocapnia (FETCO2 = 0.04) and hypercapnia in hyper-oxia. Microinjection of the sodium glutamate (50 mM, 20-30 nl) into theDM was performed to evaluate the responses of the phrenic nerve and thefacial nerve. There are two types of responses of the phrenic and facial nervesto the activition of the DM with 1.0 nmole and 1.5 nmloe sodiumglutamate injection. In type I response, phrenic activity andinspiratory facial discharges were all decreased as the DM wasactivated. Mean phrenic activities were 79.49 ± 2.09 and 76.53 ±3.31(p < 0.05) percent of control which was designate as mean nerveactivities prior to glutamate treatment. Mean inspiratory facial nervedischarge were reduced to 63.53±4.14 and 69.38±3.96 percent ofcontrol (p < 0.05). In type II response, reduction in phrenic nerveactivity in response to DM activition was not discernible. Only theinspiratory facial discharge were decreased to 72.08±4.14 and63.33 ± 7.55 percent of control (p < 0.05). In adition, expiratoryfacial discharge was excited as the DM was activated. These resultssuggest that the DM may play a role in modulating the resistance toairflow in the upper airway by controling the respiratory-modulatedfacical nerve activities.