炭酸ガス負荷時の肺迷走神経による呼吸調節—J-receptorの関与

Respiratory regulations of pulmonary vagal nerves under hypercapnic conditions:Effects of J-receptor

　気道系には3つの神経受容体が存在し，主に反射を介して呼吸運動に影響を与えている。^1,2）しかし，これらの神経反射機構が呼吸運動にどのような影響を与えているかは明確でない。そこで各神経の伝導遮断温度が異なることを利用し，炭酸ガス負荷時の呼吸運動にこれら肺末梢神経受容体がどのような影響を与えているかを明らかにすることを目的として実験を行った。

We studied ventilatory responses under hyperca-pnic condition in 9 lightly anesthetized dogs, using a vagal nerve cooling technique. One side of the cervical vagosympathetic trunks of dogs were pre-viously severed, and a copper cooler was attached to the other side. When the cervical nerve was cooled below 7℃, the Hering-Breuer inflation reflex ceased. We found that when the vagal nerve was not cooled or cooled to 7℃, the respiratory frequency increased significantly in relation to hypercapnic gas inhala-tion. However, the increment of respiratory fre-quency was reduced by bilateral cervical vagotomy. We concluded that the J-receptor is responsible for the increase in respiratory frequency under hyper-capnic gas inhalation.