Sakakibara Y
Jpn J Physiol. 1978;28(6):721-35. doi: 10.2170/jjphysiol.28.721.
CO2 sensitivity in the airways and the general skin surface of the bullfrog under urethane anesthesia or without anesthesia was investigated. Pressure in the buccal cavity as well as blood pressure in the sciatic artery were measured with a differential or a straingauge transducer. Air containing 2--14% CO2 was introduced into the regions as given below. (1) The nose and the body surface, both regions were separated from each other and independently exposed to CO2. (2) The larynx-lungs, the buccal cavity-lungs, the naso-buccal cavity separated from the airways at the glottis, and the internal or external nares, respectively. By analyzing the CO2 sensitivity of the respective regions mentioned above, both the nasal mucosa and the skin surface were found to be responsible for the respiratory inhibition by CO2. Sectioning both the olfactory and the trigeminal nerves abolished the CO2-induced inhibition mediated by the nasal mucosa and electrical stimulation of the proximal cut end of these nerves inhibited respiration. These findings suggested the existence of afferent reflex pathways from the nasal mucosa by these cranial nerves. Significance of this CO2-induced reflex was discussed.
研究了在氨基甲酸乙酯麻醉或无麻醉情况下牛蛙气道和体表对二氧化碳的敏感性。用差压式或应变式传感器测量口腔压力以及坐骨动脉血压。将含2%-14%二氧化碳的空气通入以下区域。（1）鼻子和体表，这两个区域相互分开，分别独立暴露于二氧化碳中。（2）喉-肺、口腔-肺、在声门处与气道分离的鼻-口腔以及内鼻孔或外鼻孔。通过分析上述各区域对二氧化碳的敏感性，发现鼻粘膜和皮肤表面均对二氧化碳引起的呼吸抑制起作用。切断嗅觉神经和三叉神经均消除了由鼻粘膜介导的二氧化碳诱导的抑制作用，对这些神经近端切断端进行电刺激会抑制呼吸。这些发现提示存在通过这些颅神经从鼻粘膜传入的反射通路。讨论了这种二氧化碳诱导反射的意义。
