The distribution and secretion of kallikrein in some exocrine organs of the rat

ørstavik , T. B. The distribution and secretion of kallikrein in some exocrine organs of the rat. Acta physiol. scand. 1978. 104. 431–442. Extractable kallikrein was quantitated in the submandibular, sublingual, and parotid glands and in the pancreas. No kallikrein was detected in the exorbital lacrimal glands and tears. The highest kallikrein concentrations (EU/ml) were in all major salivary gland secretions seen after α-adrenergic stimulation, less after β-adrenergic and least after parasympathetic stimulation. When taking into account the large variations in salivary flow rate, α-adrenergic stimulation was in the parotid and particularly in the submandibular gland found to result in the highest kallikrein secretory activity measured by the kallikrein secretory rate (EU/ min). This shows that the kallikrein-rich granular tubular cells are selectively activated through α-adrenergic sympathetic receptors. The differences observed in the parotid saliva were small and not always statistically significant. However, when cervical nerve stimulation was superimposed upon parasympathetic stimulation, kallikrein secretory rate as well as kallikrein concentration increased. The large individual variations in salivary gland kallikrein content and secretion and the rather small differences observed in kallikrein secretory rate after nervous stimulation of the parotid and sublingual glands, may indicate that the kalli-krein-containing striated ducts are also influenced by factors other than the secretory nerves. The kallikrein concentration and secretory rate in urine was studied. A strong positive correlation between kallikrein secretory rate and fluid volume was found in urine but not in saliva.     

The cement apparatus of larval and adult Acanthocephalus anguillae (Acanthocephala), with notes on the copulatory cap and origin of gland secretion

Light and electron microscopy were used to investigate the ultrastructure of the cement apparatus, namely cement glands and cement ducts, of mature specimens of the parasite Acanthocephalus anguillae (Müller, 1780) Lühe, 1911 recovered from the alimentary canal of fish Leuciscus cephalus (Risso, 1826). In addition, the cement apparatus of immature A. anguillae found within the body cavity of the crustacean Asellus aquaticus (L.) was examined. In immature and mature males of Acanthocephalus anguillae, there are six round cement glands and each of them has an outer cytoplasmic layer containing nuclei and surrounds a space for storage of the cement. The cytoplasmic layer produces round, membrane-bound secretory granules approximately 1 μm in diameter. Nuclei and other cellular organelles surrounded by secretory granules were noticed inside the luminal part of the gland of adult males. In some female Acanthocephalus anguillae, within the attached copulatory cap, eggs and spermatozoa were observed. A protein of about 23 kDa appeared to be the major component of proteins of isolated cement glands, as well as in detached copulatory caps. Received: 7 October 2000 / Accepted: 20 October 2000     

Structure of the corpuscles of Stannius in the euryhaline teleost Takifugu niphobles (Tetraodontiformes, Teleostei), with special regard to vascularization and extravascular channel system

Summary Vascularization and the extravascular channel system of the corpuscles of Stannius in a euryhaline teleost, Takifugu niphobles, were studied by scanning electron microscopy of the vascular corrosion cast, and histochemistry of exogenously injected horseradish peroxidase as a macromolecular tracer. The corpuscles were apposed to the caudal part of the ureter, away from the mesonephric kidney, and were supplied with arterioles from the genital artery running ventrally as a ramus of the dorsal aorta. Elaborate capillary networks irrigating the glandular lobules were collected by the venules to drain into the posterior cardinal veins. Electron microscopic examination of the glands demonstrated two types of secretory cells, type-1 cells with large granules, and type-2 cells with smaller granules. The type-1 cells, predominating in the gland, occasionally showed exocytosis of the secretory granules, mainly into intercellular spaces between adjoining cells. Exocytosis was also evident in the type-2 cells. The tracer molecule injected was visualized histochemically within the capillary lumina and intercellular spaces throughout the gland. The labelled spaces intercommunicated with each other to form an extensive extravascular channel system as a diffusing pathway within the gland. The possible role of this system in hormone transport and/or storage was discussed.This paper is dedicated to the 60th anniversary of Professor Yoshiharu Honma, Director of Sado Marine Biological Station of Niigata University     

Skin of the Red Eye Tree Frog Agalychnis Callidryas (Hylidae,Phyllomedusinae) Contains Lipid Glands of the Type Described in the Genus Phyllomedusa

Several anuran species of the genus Phyllomedusa are known to possess specialized cutaneous glands producing lipids and exhibit a peculiar wiping behavior. This behavior is a stereotyped repertory of fore and hind limb movements distributing hydrophobic molecules onto the body surface and reducing evaporative water loss. No reports are presently available on the occurrence of lipid glands in other phyllomedusine genera, and data on the structure of the secretory units specialized for the production of cutaneous lipids are still unclear. The present report is aimed to answer both questions: it describes lipid glands of the Phyllomedusa type in Agalychnis callidryas and provides light and transmission electron microscope evidence of the syncytial structure of their secretory units, a typical feature of serous glands in anuran skin. This morphological trait supports the hypothesis that lipid glands are a specialized subset of the anuran serous glands, and underlines their flexible role in the skin adaption to sub‐aerial environments. Anat Rec, 300:503–506, 2017. © 2016 Wiley Periodicals, Inc.     

Salivary Glands of the Rat in a Hot Environment

Elmér , M. and P. Ohlin . Salivary glands of the rat in a hot environment. Acta physiol. scand. 1970. 79. 129–132. A marked hypertrophy of the normally innervated submaxillary gland was observed in rats subjected to heat (34°C) for 3 weeks. The increase in weight of parasympathetically de-xiervated glands was much less while that of sympathetically denervated glands was still pronounced. The size of both synipathetically and parasympathetically denervated glands was not affected in a hot environment. It seems likely that the hypertrophy of the submaxillary gland is to a large extent secondary to an increased secretory activity elicited by the para-sympathetic secretory fibres. A corresponding increase in weight of the sublingual gland was not seen.     

Neurokinin A in the parotid and submandibular glands of the rat: immunohistochemical localization and effect on protein and peroxidase secretion

An indirect immunofluorescence technique was used to study the distribution of neurokinin A immunoreactive (NKA-IR) nerve fibres in submandibular and parotid glands of the rat. The functional role of neurokinin A on protein and peroxidase secretion in these glands was evaluated by using in vitro methods. In the parotid gland neurokinin A immunoreactive fibres were mainly distributed around the secretory acini, but some were also in evidence around the stromal blood vessels and ducts. The number of the neurokinin A immunoreactive nerve fibres was lower in the submandibular gland than in the parotid gland. They were mainly distributed around the secretory acini and stromal blood vessels and ducts. In vitro, neurokinin A significantly stimulated the release of total amount of released proteins and peroxidase from parotid gland fragments, while in the submandibular gland only the release of peroxidase was increased. By using SDS polyacrylamide gel electrophoresis (SDS-PAGE) specific changes were found in the release of proteins after neurokinin A stimulation. The results of the present study demonstrate that neurokinin A immunoreactive nerve fibres are present in the rat parotid and submandibular glands. Their localization around the secretory elements of the glands and the effect of neurokinin A in vitro experiments indicates that neurokinin A might have a significant role in the regulation of salivary secretion.     

Differential distribution of salivary agglutinin and amylase in the Golgi apparatus and secretory granules of human salivary gland acinar cells

The secretory granules of salivary glands often display complex internal substructures, yet little is known of the molecular organization of their contents or the mechanisms involved in packaging of the secretory proteins. We used post-embedding immunogold labeling with antibodies to two secretory proteins, agglutinin and α-amylase, to determine their distribution in the Golgi apparatus and secretory granules of the human submandibular gland acinar cells. With monoclonal antibodies specific for carbohydrate epitopes of the agglutinin, reactivity was found in the trans Golgi saccules, trans Golgi network, and immature and mature secretory granules. In the granules, labeling was seen in regions of low and medium electron density, but not in the dense cores. Reactivity seen on the apical and basolateral membranes of acinar and duct cells was attributed to a shared epitope on a membrane glycoprotein. Labeling with a polyclonal antibody to amylase was found in the Golgi saccules, immature and mature secretory granules, but not in the trans Golgi network. In the granules, amylase was present in the dense cores and in areas of medium density, but not in the regions of low density. These results indicate that these two proteins are distributed differently within the secretory granules, and suggest that they follow separate pathways between the Golgi apparatus and forming secretory granules. Small vesicles and tubular structures that labeled only with the antibodies to the agglutinin were observed on both faces of the Golgi apparatus and in the vicinity of the cell membrane. These structures may represent constitutive secretion vesicles involved in transport of the putative membrane glycoprotein to the cell membrane.     

Characterization of the myoepithelial cells in the major salivary glands of the fruit bat Artibeus jamaicensis

Bats constitute one of the most numerous mammalian species. Bats have a wide range of dietary habits and include carnivorous, haematophagous, insectivorous, frugivorous and nectivorous species. The salivary glands of these species have been of particular research interest due to their structural variability among chiropterans with different types of diets. Myoepithelial cells (MECs), which support and facilitate the expulsion of saliva from the secretory portions of salivary glands, are very important for their function; however, this cell type has not been extensively studied in the salivary glands of bats. In this study, we characterized the MECs in the major salivary glands of the fruit bat Artibeus jamaicensis. Herein, we describe the morphology of the parotid, submandibular and sublingual glands of A. jamaicensis at the light‐ and electro‐microscopic level and the distribution of MECs in these glands, as defined by their expression of smooth‐muscle markers such as α‐smooth muscle actin (SMAα) and desmin, and of epithelial cell markers, such as KRT14. We found that the anatomical locations of the major salivary glands in this bat species are similar to those of humans, except that the bat sublingual gland appears to be unique, extending to join the contralateral homologous gland. Morphologically, the parotid gland has the characteristics of a mixed‐secretory gland, whereas the submandibular and sublingual glands were identified as mucous‐secretory glands. MECs positive for SMAα, KRT14 and desmin were found in all of the structural components of the three glands, except in their excretory ducts. Desmin is expressed at a lower level in the parotid gland than in the other glands. Our results suggest that the major salivary glands of A. jamaicensis, although anatomically and structurally similar to those of humans, play different physiological roles that can be attributed to the dietary habits of this species.     

The dynamic behaviour of Hassall's corpuscles and the transport of particulate matter in the thymus of the guinea-pig

Young immature guinea-pigs, 7–10 weeks old, were exposed to X-rays directed solely to the thymus gland which received a tissue dose of 300 r. An equal number of animals were not irradiated. All the animals had an intracardiac injection of 0.3 ml of Indian ink containing 10 per cent carbon of uniform particle diameter. An increase in number and size of Hassall's corpuscles was noted in irradiated thymus glands. Simultaneously, there was an increase in the uptake of carbon in the walls of blood vessels and in perivascular macrophages. Within 12 hours of irradiation Hassall's corpuscles contained carbon, at first in a finely stippled form in polymorphonuclear leucocytes and, later, in larger aggregates in macrophages. After an interval of 14 days Hassall's corpuscles disappeared and the lobules were re-populated with thymocytes. Migration outwards of carbon laden macrophages occurred between the 14th and 21st days. By contrast the entry of carbon in control glands took place more slowly but retention of particulate matter in Hassall's corpuscles was still present at the end of the experimental period of 56 days.

It is suggested that Hassall's corpuscles are a `graveyard' for dead thymocytes, possibly for some effete circulating lymphocytes and in some circumstances for polymorphonuclear leucocytes. It is also suggested that antigens localize in Hassall's corpuscles. Furthermore, since γ-globulin is known to localize there, these antibodies may be mobilized and returned to the circulation by macrophage activity.

     

Comparative anatomy and phylogeny of the cloacae of salamanders (Amphibia: Caudata) IV. Salamandridae

Cloacae were examined from male and female salamanders representing 12 genera and 22 species in the Salamandridae. All female salamandrids possess numerous sperm storage glands, spermathecae, in the roof of the cloaca, but intergeneric variation exists in the occurrence of additional cloacal glands. Pleurodeles and Tylototriton possess both vent and anterior ventral glands, and secondary loss has occurred of vent glands in all other genera and anterior ventral glands in Chioglossa, Cynops, Paramesotriton, and Triturus The most highly derived cloaca occurs in Euproctus asper, in which the cloacal tube extends through a conical projection, and ventral glands secrete onto the dorsolateral surface of the projection rather than into the cloaca. Marked intergeneric variation occurs in males in conformation of the cloacal cavities and in extent of the dorsal gland. In Cynops, Euproctus, Pachytriton, Paramesotriton, Taricha, and Triturus, the pseudopenis (a broad, posteriorly projecting evagination of the dorsal roof) fills much of the cavity of the anterior cloacal chamber. In most salamandrids, distal ends of the dorsal glands occur lateral to pelvic glands in the anterior end of the cloaca, and dorsal gland tubules descend to secretory sites at the posterior end of the vent. Salamandra and Mertensiella possess a unique, bifurcated dorsal gland in which distal ends of tubules lie dorsal to the other cloacal glands, and proximal ends curve ventrally in the anterior end of the cloaca to secretory sites along the cloacal orifice. Cladistic analyses indicate that the variation in presence of anterior ventral glands is due to homoplasy. The occurrence of female vent glands, bifurcated dorsal glands, and the pseudopenis supports a phylogeny based upon noncloacal characters. © 1992 Wiley-Liss, Inc.     

Morphology of the exocrine glands of the frog skin

Frog skin contains three distinct types of exocrine glands: granular (poison), mucous, and seromucous. The granular gland forms a syncytial secretory compartment within the acinus, which is surrounded by smooth muscle cells. The mucous and seromucous glands are easily identifiable as distinct glands. The serous and mucous secretory cells are arranged in a semilunar configuration opposite the ductal end and are filled with granules. Within the acinus, located at the ductal pole of the gland, are distinct groups of cells with few or no granules in the cytoplasm. In both the mucous and seromucous gland there is a cell type with abundant mitochondria; the one in the mucous gland is located in the region adjacent to the secretory cells. The duct of these glands is two-layered, with the individual cells appearing morphologically similar to the layers of the skin epithelium as the duct traverses the skin. The duct appears to be patent throughout its length. The morphological heterogeneity and distinct distribution of the cell types within the gland acinus may be indicative of a functional heterogeneity that allows the production of distinctly different types of secretion from the same gland type, depending on the type of stimulus.     

Phenotype of mononuclear leucocytes resident in rat major salivary and lacrimal glands.

The phenotypic distribution of lymphocytes and mononuclear phagocytes resident in rat secretory glands was examined. Isolated exocrine gland mononuclear leucocyte populations contained 50-61% W3/13+ T cells and greater proportions of W3/25+ T helper cells relative to OX8+ T suppressor cells. Surface Ig+ cells (sIg) constituted from 32% to 34% of the cells and their distribution was sIgM greater than sIgA greater than sIgG. The macrophage populations comprised from 0.02% to 0.1% of the unfractionated gland cells. Fractionated secretory gland-adherent cells consisted primarily of non-specific esterase+, phagocytic and Fc receptor-bearing cells. From 35% to 79% of the macrophages in exocrine glands expressed I-A molecules. The results suggest that exocrine glands have the ability to respond locally to an antigenic challenge independently of a central mucosal immune response.     

Changes in glycoconjugates revealed by lectin staining and stage-specific embryonic antigen-1 immunostaining in hamster submandibular glands during the postnatal period

Lectin binding and stage-specific embryonic antigen-1 (SSEA-1) immunoreactivity were studied in the developing submandibular glands of young Syrian golden hamsters (Mesocricetus auratus) from postnatal day 1 (the day of birth) to day 28. The submandibular glands were fixed in a solution containing 6% mercuric chloride, 1% sodium acetate, and 0.1% glutaraldehyde (HgCl₂-G) or 4% paraformaldehyde (4P), and embedded in paraffin. Sections from HgCl₂-G fixation were stained with three lectin-peroxidase conjugates: peanut agglutinin (PNA), Ulex europeus I agglutinin (UEA I), and wheat germ agglutinin (WGA). Sections from the 4P-fixed tissues were immunostained with monoclonal antibodies against SSEA-1, sialyl SSEA-1 and fucosyl SSEA-1. On the day of birth, the terminal unit of the submandibular gland was composed of fetal type secretory cells and proacinar cells. The secretory cells were PNA, UEA I, and WGA positive. The number of secretory terminal tubule cells decreased rapidly, and lectin-positive secretory cells were replaced by adult secretory cells that did not show PNA or UEA I stainings but were weakly positive for WGA. Fetal secretory cells were positively immunostained for SSEA-1 and sialyl SSEA-1, and immature ductal cells were stained for fucosyl SSEA-1. The positive stainings disappeared with regression of the fetal epithelial cells. Hence, modulation of glycoconjugate expression in the submandibular glands, which reflects changes in secretory cells from the fetal type to adult type during postnatal development, is revealed by lectin staining and immunostaining for SSEA-1 and related antigens.     

Histophysiological evidence for the secretion of polypeptides by the pineal gland

Histophysiological examinations of the bovine and monkey pineal gland indicate that this organ may be involved in the secretion of polypeptides. Using various histochemical procedures designed to identify peptidesecreting cells, granules and/or droplets of presumptive secretory product were identified within cellular processes, within the walls of blood vessels and associated with multilayered corpuscles (corpora arenacea). In bovine pineal tissue, the stained material was found most often in what appeared to be pinealocyte processes, as perivascular granules and associated with multilayered corpuscles. In the monkey pineal the stainable material was more distinct; this was probably due to the earlier fixation of the glands after death of the animals. In this species, the presumptive secretory material was found in nerve fibers, occasionally in glial cell and pinealocyte processes and within and around the walls of capillaries. In nerve fibers, the stained material sometimes resembled Herring bodies of the posterior pituitary gland. Similar material appeared to be located in capillary endothelial cells and within multilayered corpuscles. In pineal tissue of both species, calcium was detectable histochemically within multilayered corpuscles. Although tinctorially different, the presumptive neurosecretory material was similar to that found in the posterior pituitary gland. As a working hypothesis, we propose that polypeptides may be released from cells in conjunction with a carrier protein and that the mechanism of secretion of the polypeptide into the vascular system may involve its exchange for calcium. The calcium is then theoretically deposited in the multilayered corpuscles.     

Ultrastructure of the human anogenital “sweat” gland

A newly described type of cutaneous gland occurring in the human anogenital region was investigated in specimens from the vulva by electron microscopy. This gland, which is characterized by a long excretory duct opening at the skin surface, by a wide coiled secretory part with multiple lateral extensions in the form of diverticula and branches lined by a two-layered pseudostratified of myoepithelium, and by a luminal layer of tall columnar cells with conspicuous “snouts”, could not be categorized as an eccrine, apocrine, or mammary gland. Electron microscopy confirmed its separate position by showing that the luminal layer of secretory cells with prominent cytoplasmic caps had elaborately folded lateral membranes, occasional canaliculi, and a large number of uniform electron-lucent to moderately electron-dense secretory granules as part of a probable merocrine secretion. The excetory duct showed a poorly developed cuticular border. This combination of ultra-structural features is alien to the other tubular cutaneous glands. The function of this anogenital “sweat” gland remains obscure, but the presence of these granules suggests a secretion product that is different from that of other cutaneous glands. © 1993 Wiley-Liss, Inc.     

Sensory Innervation of the Female Human Umbilical Skin: Morphological Studies

Background: Sensory stimuli are conducted by several cutaneous sensory nerves and tactile corpuscles. The latter are specialized sensory organs that represent the starting point of many afferent sensory pathways. To date, our knowledge about the distribution of the sensory innervation in the umbilical skin of females is incomplete.

Aim of the study: To elucidate the morphology of the cutaneous innervation of the normal female umbilical skin.

Materials and methods: Biopsies of normal umbilical skin were obtained from female patients undergoing umbilical hernial repair. The specimens were processed for both immunohistological (antibodies against PGP9.5, pan-neuronal marker, and S-100 protein, marker of Schwann cells) and ultrastructural (transmission electron microscopy) examinations.

Results: The authors found abundant genital end-bulb-like structures, numerous epidermal and dermal Merkel cells, Meissner and Ruffini corpuscles, intraepidermal nerve terminals, and multiple free nerve endings surrounding the ducts and acini of the sweat glands.

Conclusions: The umbilical skin of females has abundant sensory innervation similar to that of the glans penis.     

The uptake and localization of proteins, Evans Blue and carbon black in the normal and pathological thymus of the guinea-pig

Radioiodine-labelled homologous serum albumin and heterologous γ-globulin reached the extravascular space of the guinea-pig thymus in concentrations comparable with those in the spleen and in lymph-nodes. The uptake of proteins in a locally X-irradiated involuting thymus gland was approximately doubled at 6, 12, 24 and 48 hours compared with non-irradiated controls. At 7 days the concentration was greater than in the other lymphoid tissues examined, namely spleen, cervical and mesenteric lymph-nodes, and was greater than in control glands by a factor of two to four.

Localization of foreign material was studied with Evans Blue and carbon black which were found in macrophages of the capsule, cortex and medulla, and in Hassall's corpuscles. The foreign material showed a marked increase in the parenchyma of glands during involution whether produced by X-irradiation, cortisone or corticotrophin.

The significance of these findings in relation to the formation of germinal centres in the thymus in pathological conditions is discussed.

     

Ultrastructure of the principal and accessory submandibular glands of the common vampire bat

The principal and accessory submandibular glands of the common vampire bat, Desmodus rotundus, were examined by electron microscopy. The secretory endpieces of the principal gland consist of serous tubules capped at their blind ends by mucous acini. The substructure of the mucous droplets and of the serous granules varies according to the mode of specimen preparation. With ferrocyanide-reduced osmium postfixation, the mucous droplets are moderately dense and homogeneous; the serous granules often have a polygonal outline and their matrix shows clefts in which bundles of wavy filaments may be present. With conventional osmium postifixation, the mucous droplets have a finely fibrillogranular matrix; the serous granules are homogeneously dense. Mucous cells additionally contain many small, dense granules that may be small peroxisomes, as well as aggregates of 10-nm cytofilaments. Intercalated duct cells are relatively unspecialized. Striated ducts are characterized by highly folded basal membranes and vertically oriented mitochondria. Luminal surfaces of all of the secretory and duct cells have numerous microvilli, culminating in a brush borderlike affair in the striated ducts. The accessory gland has secretory endpieces consisting of mucous acini with small mucous demilunes. The acinar mucous droplets contain a large dense region; the lucent portion has punctate densities. Demilune mucous droplets lack a dense region and consist of a light matrix in which fine fibrillogranular material is suspended. A ring of junctional cells, identifiable by their complex secretory granules, separates the mucous acini from the intercalated ducts. The intercalated ducts lack specialized structure. Striated ducts resemble their counterparts in the principal gland. As in the principal gland, all luminal surfaces are covered by an array of microvilli. At least some of the features of the principal and accessory submandibular glands of the vampire bat may be structural adaptations to the exigencies posed by the exclusively sanguivorous diet of these animals and its attendant extremely high intake of sodium chloride.     

Secretory effects of 5-hydroxytryptamine following neonatal sympathectomy in rat parotid gland

Unilateral sympathetic denervation of rat parotid glands was performed within 4 h after birth. Nine weeks later the glands were used for in-vitro studies of amylase secretion, and ⁸⁶Rb+ was used as a marker for potassium efflux. The non-denervated contralateral glands served as controls. The tissue concentrations of 5-hydroxytryptamine and its metabolite 5-hydroxyindole acetic acid were also measured. 5-Hydroxytryptamine caused a significant dose-dependent increase in amylase secretion, which was inhibited by methysergide. There was no difference between controls and denervated glands. 5-Hydroxytryptamine was without effect on potassium efflux from either denervated or control glands. The sympathectomy caused increased levels of 5-hydroxytryptamine and 5-hydroxyindole acetic acid as compared with contralateral controls. The results suggest that 5-hydroxytryptamine influences the two main secretory processes in rat parotid gland differently. A significant amylase discharge was seen following 5-hydroxytryptamine stimulation, whereas no effect was seen on ⁸⁶Rb+ efflux. Although it is also proposed that there are no 5-hydroxytryptamine-associated nerves in the superior cervical ganglion innervating parotid tissue, it seems that there is a complex connection between the sympathetic pathway and the serotoninergic system.