Immunohistochemical study of the lymphatic vessels in major salivary glands of the rat.

This study was designed to examine whether lymphatic vessels are present in the lobules of major salivary glands in the rat. Immunostaining with an antibody against podoplanin, a lymphatic endothelial cell marker, was performed on sections of the submandibular, sublingual and parotid glands. Light microscopy demonstrated podoplanin-positive lymphatic vessels around the interlobular ducts and the interlobular arteries and veins in the interlobular connective tissue in all of the major salivary glands.

Changes in the properties of secretory granules in the palatine gland acinar cells of the postnatally developing rat.

This study was designed to examine whether or not phospholipid is contained in the secretory granules of the rat palatine gland acinar cells, and if present, to examine the movements of phospholipid in the secretory granules during postnatal development. The palatine glands of male Wistar rats aged 0 to 56 days were used. Acid-hematin staining showed a few positive acinar cells with a faint reaction in the acini on day 0, numerous positive cells with an intense reaction on day 7, a weakening reaction in the cells on day 14, and almost no reactivity on day 35 and after.

Strain-specific and endocrine control of granular convoluted tubule cells and epidermal growth factor expression in the mouse submandibular gland.

Submandibular glands (SMGs) of 11-week-old mice from four strains, ICR, C57BL/6J, BALB/c, and C3H/HeN were examined by immunohistochemistry for epidermal growth factor (EGF). In addition to sex-related differences in granular convoluted tubules (GCTs), the GCT cells were significantly larger in ICR mice than in other three strains. In males from each of the strains, almost all the GCT cells were strongly positive for EGF.

Effects of exogenous thyroid hormone on the postnatal morphogenesis of the rat parotid gland.

Administration of thyroid hormone has been shown to accelerate the early postnatal development of the rat parotid gland, but these studies have dwelt almost entirely on biochemical changes. The objective of this study was to describe the effects of exogenous thyroid hormone on morphologic aspects of the developing parotid gland, in particular the transient appearance of scattered mucous cells in this otherwise serous gland. Pups were given a daily subcutaneous injection of thyroxine (T(4)) of 0.

Effect of glucocorticoid on the differentiation and development of terminal tubules in the fetal rat submandibular gland.

Glucocorticoids (CORT) are known to promote branching of the epithelial cords during the development of the rat submandibular gland. The aim of this study was to examine the effect of CORT (triamcinolone) on the differentiation of cells forming the terminal tubules in the developing fetal rat submandibular gland and the properties of the secretory granules. Light and electron microscopy showed that the terminal tubules of the glands in the experimental group contained more type III cells, which have been identified as proacinar cells, than those in the control group, whereas the relative number of type I cells, which have been identified as terminal tubule cells, was reduced.

Histological analysis of the sublingual gland in rats with streptozotocin-induced diabetes.

This study was designed to examine whether the sublingual gland parenchyma is influenced by the development of insulin-dependent diabetes mellitus. The sublingual glands of rats with streptozotocin-induced diabetes were examined by light and electron microscopy. In order to define the limiting membrane of mucous granules in more detail, samples processed by rapid freezing following by freeze-substitution in addition to chemical fixation were also prepared for electron microscopy.

Morphological changes in the rat sublingual gland parenchyma with aging.

Background: The characteristics of mucous cells in the aging rat sublingual gland were investigated in this study. Particular attention was paid to accumulated amyloid protein and changes of the properties of the secretory granules at the histochemical and ultrastructural level.

Objective: This study was designed to examine age-related morphological changes in the sublingual gland of male Wistar rats from 12 to 27 months.

Changes in the number and distribution of myoepithelial cells in the rat parotid gland during postnatal development.

The mature rat parotid gland shows hardly any cell bodies of myoepithelial cells around the acini, only a few cell processes being visible. However, in the early postnatal period, the rat parotid gland shows many myoepithelial cell bodies around the acini, including the intercalated ducts. In order to clarify the reason for the disappearance of myoepithelial cells from the area around the acinus during postnatal development, changes in the number and distribution of myoepithelial cells in the rat parotid gland were examined histochemically and chronologically, with particular reference to cell proliferation and cell death.

Three-dimensional observation of blood vessels supplying the gland proper and capsule of the mouse submandibular gland.

Previous studies have shown that submandibular glands suffering interruption of the blood circulation from the main supplying artery have more surviving parenchymal cells in their peripheral portion than in their central portion. Although the reason for this difference between the peripheral and central portions has not yet been clarified, the existence of collateral circulation has been suspected. The present study was designed to examine whether or not the vessels binding the gland proper to the capsule provide such collateral circulation.

Changes in the distribution and fine structure of the intralobular blood vessels of the submandibular gland in the postnatally developing mouse.

Previous studies have shown that the blood vessels supplying the endocrine organs and the mucosa of the intestinal canals change in terms of not only their distribution but also their structure with the development and growth of each organ. We examined changes in the distribution and structure of intralobular blood vessels, including capillaries, throughout the postnatal development of the submandibular gland, an exocrine organ. The mouse submandibular gland from days 0 (birth) to 49 was investigated chronologically and ultrastructurally.

Role of thyroid hormone in the initiation of EGF (epidermal growth factor) expression in the sublingual gland of the postnatal mouse.

The effect of triiodo-L-thyronine (T3) and propylthiouracil (PTU) on the initiation of epidermal growth factor (EGF) expression in the sublingual glands (SLGs) of postnatal mice was investigated by indirect enzyme-labeled and immunogold antibody methods for light and electron microscopy, respectively. In normal males, EGF immunoreactivity first appeared in a few scattered granular cells of striated ducts (SDs) at 5 weeks of age, and the immunoreactive cells had increased in number at 6 weeks of age. No EGF expression was observed in the glands of females at any ages examined.

Lateral expansion of the rat lower dental arch by applying an active plate model to the mandibular first molar region: observation of histological changes in the lower alveolar bone over a 2-week period.

Lateral expansion of the lower dental arch has rarely been conducted clinically because the structure of the lower jaw is considered to be unsuitable for this type of treatment. However, successful lateral expansion of the lower dental arch using SCHWALZ, an orthopedic appliance has been reported in recent years. Therefore, an experimental study was performed to examine the histological changes in the lower alveolar bone when lateral expansion is applied to the lower dental arch for periods of up to 2 weeks.

Granule types and their morphological changes in terminal cluster and acinar cells in the late pre- and early postnatal rat sublingual gland.

The developmental characteristics of serous cells appearing in the rat sublingual gland from the late prenatal to the early postnatal period were investigated in this study. Particular attention was paid to the morphological changes observed in the secretory granules at the histochemical and ultrastructural level. On prenatal day 18, granules with homogeneous high electron density (Type I granules), and mottled granules (Type II granules) with heterogeneous electron density appeared in the narrow luminar cytoplasm of cells constituting the terminal clusters.

Effects of gadolinium and tetrodotoxin on the response of slowly adapting type I mechanoreceptors to mechanical stimulation in frog dorsal skin.

To elucidate the excitatory mechanism of mechanoreceptors innervating the frog skin, we examined the effects of gadolinium (Gd3+) and tetrodotoxin (TTX) on the response of single-unit activity of slowly adapting type I mechanoreceptors to mechanical stimulation topically applied to the receptive field (RF). Recordings were made from 46 fibers responding to mechanical stimulation with von Frey hairs, which caused an irregular firing pattern with slow adaptation. Application of a mechanically gated channel blocker, Gd3+ (30 microM), and a Na+ channel blocker, TTX (3 microM), caused the suppression of discharge rates, which was characterized by the conversion of a slowly adapting to a rapidly adapting discharge pattern.

Morphological changes in mouse sublingual gland parenchyma subjected to chorda tympani resection.

Morphological changes in the mouse sublingual gland parenchyma subjected to parasympathetic nerve block were investigated. Mice were subjected to unilateral resection of the chorda tympani, near its point of joining with the lingual nerve. After 1, 2, 3, 5, 10 or 20 weeks, the mice were killed and their sublingual glands were removed and processed for light and electron microscopy.