<原著>交感神経の肺内分布に関する研究 Falck-Hillarp の螢光法を応用して

Abstract

By means of Falck-Hillarp's fluorescence method and Staub's rapid freezing method, the distribution of fluorescent, sympathetic postganglionic fibers was studied in the lungs of the rabbit, guinea-pig and man under conditions as physiological as possible. No great differences were found in the intrapulmonary pulmonary arteries and bronchi of these three species. In pulmonary arteries and bronchi, nerve plexuses appeared, morphologically, to be separate, but physiologically, they seemed unified to form a single "broncho-pulmonary arterial" plexus, because of the abundance of communicating twigs between the two. In the walls of the pulmonary arteries, almost all fluorescent fibers were found in the border between the adventitia and media. Finer fibers branched off from thicker ones to form a meshwork. The smaller the arteries, the less dense was the fluorescence. No fluorescence was seen in arteries with an inside diameter less than 100μ, and in precapillaries or capillaries. Very few fluorescent fibers entered the medial smooth muscle layer, and the intima showed no specific fluorescence. In the intrapulmonary bronchi with cartilaginous tissues, fluorescence was more dense inside this tissue (subchondrial plexus) than outside (extrachondrial plexus). Fluorescence was most marked in the bronchial vessels, which exhibited it when they were even as small as 20μ in diameter. The bronchial smooth muscle layers and submucosa showed much fluorescence almost equally. However, the submucosal fluorescence appeared to originate from the peribronchial arterial plexus. The submucosal plexus decreased in quantity with the size of the bronchi, and the bronchi with no cartilage had only a peribronchial nerve plexus. In the periphery, the bronchi showed less fluorescence than the pulmonary arteries. Rabbit lungs showed no fluorescence of intrapulmonary pulmonary veins, while in guinea-pigs and man there was some in the veins but much less than in the pulmonary arteries. Since there were no fluorescence in the lung parenchyma and no communicating branches between the perivenous plexuses and those around the bronchi and pulmonary arteries, the previous plexus seems to be a separate, independent nerve plexus.