Nosaka S, Yasunaga K, Tamai S
Am J Physiol. 1982 Jul;243(1):R92-8. doi: 10.1152/ajpregu.1982.243.1.R92.
In chloralose- and urethan-anesthetized rats, the cardiac branch (CB) of the vagus nerve was electrically stimulated, and antidromic responses of medullary cells were recorded. The cells identified as the vagal cardiac preganglionic neurons (VCPN) were localized in the dorsal motor nucleus (ND group, 8 cells), a region in and around the nucleus ambiguus (NA group, 7 cells) and an intermediary zone (IM group, 2 cells) lying in between. Latencies of the antidromic responses were distinctly different among the three groups, and calculated conduction velocities indicated that the VCPN of the ND group possess C-fiber axons whereas those of the NA group and probably of the IM group, B-fiber axons. In another series of experiments, the right carotid sinus nerve (CSN) or the left cervical vagus nerve was stimulated, and efferent fiber group(s) mediating reflexly evoked discharges to the CB was determined by means of two-point recordings. Among reflex discharges evoked by stimulation of the CSN the shortest latency reflex was proved to be mediated by B-efferent fibers. In contrast, among reflex discharges evoked by stimulation of the vagus nerve, the greatest reflex component was found to be conveyed by C-efferent fibers. It was concluded that the VCPN consist of two types of cells, each located in a different region of the medulla oblongata and contributing to vagal cardiac reflex mechanisms in a different manner.
在水合氯醛和乌拉坦麻醉的大鼠中，对迷走神经的心支（CB）进行电刺激，并记录延髓细胞的逆向反应。被鉴定为迷走神经心脏节前神经元（VCPN）的细胞定位于背运动核（ND组，8个细胞）、疑核及其周围区域（NA组，7个细胞）以及位于两者之间的中间带（IM组，2个细胞）。三组之间逆向反应的潜伏期明显不同，计算得出的传导速度表明，ND组的VCPN具有C纤维轴突，而NA组以及可能的IM组的VCPN具有B纤维轴突。在另一系列实验中，刺激右侧颈窦神经（CSN）或左侧颈迷走神经，并通过两点记录法确定介导反射性诱发向CB放电的传出纤维组。在刺激CSN诱发的反射放电中，最短潜伏期反射被证明是由B类传出纤维介导的。相反，在刺激迷走神经诱发的反射放电中，最大的反射成分是由C类传出纤维传导的。得出的结论是，VCPN由两种类型的细胞组成，每种细胞位于延髓的不同区域，并以不同的方式参与迷走神经心脏反射机制。
