各種動物の口腔組織神経分布に関する研究 : (その VI)白鼠唾液腺の神経分布に関する研究

Abstract

Nerve distribution in the salivary glands of adult rats and possible relation between the patterns of distribution in successive stages of the growing glands were investigated histologically. For the initial phase of study, three major glands from adult albino rats, and for the second, the parotid gland specimens successively taken from infant animals directly after birth, were respectively used. The results were summarized as follows. Nerve Distribution in Adult Salivary Glands : 1. Submandibular and sublingual glands in the albino rats were enclosed in the same integument and had a hilus in common. There were in the connective tissus of the hilus numerous nerve cells forming ganglia of varying sizes. In the parotid gland, however, similar nerve cells were found neither in the hilus region nor in the glandular body. 2. The majority of nerve fibers entering in the salivary glands assume the appearance of socalled terminalreticulum which is known as normal terminal form of the vegetative nervous system, and in this form were they distributed in the terminal acini, over the entire duct systems and the wall of blood vessels nourishing the glandular body. since anastomosis was observed to occur everywhere between each terminalreticulum, it was thought improbable that it exerted some sort of autonomous nervous regulation on its limited region. In fact, all these terminalreticulums formed together an integrated system of network. Microscopic differentiation of the reticulums as to whether they were of sympathetic or parasympathetic origin could not be determined. 3. Coming out of these terminalreticulums, there were seen fibers of more finer structure distributed in the terminal acini, granular ducts and striated ducts, entering as far as into individual acinus, between individual cells of the acinus and into the duct cells and their periphery. The ways in which these fibers were distributed in those parts of the organ could be by appearance divided into two types. In the one type the fibers were seen as a single strand thickly stained with silver, and in another they run in varicose fibrils forming broom or network structure. The former type was mainly seen in the striated ducts and granular ducts, the latter type mainly in the terminal acini. 4. As the ways in which nerves distributed themselves differed with each individual parts of the organ, so the amounts of nerve supply also differed from one locus to another of the same organ and from one gland to another. In the parotid and sublingual glands, the most abundant nerve supply was seen in the terminal acini, followed by the striated and intercalated ducts in this order, and it was poorest in the glandular duct where hardly any sign of nerve supply was observed. In the submandibular gland, however, extremely abundant supply of nerve fibers was found in the granular ducts having the anatomical feature characteristic of this gland. The nerve supply for the remaining parts of the gland followed the patterns similar to that described for parotid and sublingual glands. Amounts of nerve supply were not homogeneous even within each section of the same organ through every glands. 5. In the hilus part there were observed a few instances of a simple, sharply tapered free endings usually encountered in the terminal form of sensory nerve and another terminal form resembling the glomerate ending, through every glands examined. Relation between Growth of Parotid Gland and Its Nerve Supply : In the parotid glands of the post-natal animals, there was seen a multitude of clusters of immature cells, dispersed in the loose fabric of connective fibers. At this earliest stage, around the clusters of immature cells which still lacked basilar membrane, the nerves distributed themselves in the form of the terminalreticulum consisting of extremely fine fibrils. These terminal apparatus were also seen distributed in the connective tissue binding the