Quantitative histoenzymologic characteristics of the submaxillary salivary glands of white rats during an ovarian cycle]

Ovarian cycle in albino rats was applied to ascertain the problem of the relationship between the salivary and endocrine glands, and also of the extent of participation of individual components of the salivary glands with different functional orientation in the endocrine regulation of individual components of the salivary glands. The content of protein, mucopolysaccharides, DNA, and RNA, the activity of NAD- and NADP-diaphorase, alkaline phosphatase, malate and isocitrate dehydrogenase, alpha-leucine-aminopeptidase was studied. Cytospectrophotometric analysis showed that synchronous changes in the activity of the enzymes under study occurred in all the portions of the salivary glands, depending on the ovarian cycle phases. Of the four successive phases of the cycle the greatest activity of the enzymes and of the protein and mucopolysaccharide content was noted during the proestrus and metaestrus. Different metabolic processes were observed in the salivary ducts in comparison with other parts of the gland; this was apparently connected with peculiarities of the secretion and hormone production.     

An electron microscopic study of the salivary gland of Rhynchosciara angelae

Summary The structure of the salivary gland of the dipteran insect Rhynchosciara angelae in a defined stage of the larval development, characterized by the synthesis and storage of secretion product, is described. Observations were made with both Nomarski optics and electron microscopy. Filiform projections extending into the lumen of the gland were observed in the apical portion of the cells. At the basal region junctions, characterized as hemidesmosomes, were observed between the membrane of the cell and the basal lamina. The plasma membrane presents numerous infoldings into the cell increasing considerably the surface area at this region. Throughout the cytoplasm of the gland cells numerous mitochondria, Golgi complexes, microtubules, profiles of endoplasmic reticulum, secretion granules and glycogen granules were observed. Carbohydrates were detected on ultrathin sections by using the periodic acid-silver methenamine and the periodic acid-thiosemicarbazide-silver proteinate techniques.     

Functional morphology of the submandibular salivary glands of white rats during aging involution]

Functional morphology of different zones of submandibular glands of albino rats was studied quantitatively with due regard for the stages of neuroendocrine system involution. It is shown that function of salivary glands during ageing is not altered; cyclic fluctuations with estral cycle phases are maintained similarly to those in young animals. But the basal level of proteins and mucopolysaccharides is reduced, their mean levels being equal to the minimal level in young animals. On the other hand, activation of enzymes responsible for energy and transport processes takes place and their relationships change. The data obtained prove the relationship between salivary and endocrine glands and confirm the viewpoint that in early age involution disintegration occurs between different parameters of the functional activity of salivary glands rather than there take place changes in their function.     

Secretory and immunocompetent functions of the parotid and submaxillary salivary glands after thymectomy]

The dynamics of morphological, enzymatic and immunologic salivary glands indices in pubertal rates was investigated after thymectomy. The data obtained analysis demonstrated the functional salivary glands reconstruction, having immunologic and secretory characteristics: stimulation of the humoral and cellular immunity factors; reduction of the albuminous and rise of the mucous salivary glands component represented the remote effect of thymectomy /3 months]. Activation of the salivary glands immune characteristics may be explained by their belonging to the thymic-peripharyngeal complex.     

Tolerance to heat of rats treated by beta-blocker. Role of submaxillary salivary glands

Effect of beta-adrenoceptor blockade on the changes in rectal temperature (RT), heat production (HP) and noradrenaline (NA) concentration in the submaxillary salivary glands (SMSG) of rats exposed to heat (45 degrees C) was studied. Propranolol (P) (15 mg/kg i.p.) decreased the tolerance to heat. The survival time of propranolol-treated (PT) rats was 30 min shorter. The temperature curve of control rats exposed to heat can be divided into three phases: a rapid rise in RT; a plateau (TP) and a prelethal increase. In PT animals, under identical conditions, TP disappears and RT further rises accelerating death. In the initial phase of heat exposure, HP was markedly decreased to the same extent in both experimental groups; but after 20 min HP increases in PT rats. The content of NA from SMSG both in the initial phase and in the TP phase is modified in PT rats.     

I. Ultrastructure of acinar cell granules in mammalian submaxillary glands

Summary Granules in acinar cells show considerable variations in size, shape, electron-density and molecular organisation of secretory material. Discrete organelles with an electron-dense homogenous matrix are seen in the guinea-pig and to some extent in the male hamster. Similar organelles with moderate electron-density are seen in the cat and dog. Acinar cells of the cat, hamster, guinea-pig and to a lesser extent the rat, contain discrete, pale granules and also confluent organelles arising from two to three of the pale particles. Composite, electron-pale secretory units are observed in the dog and rabbit.No correlation could be elicited between the histochemical reactivity of the acinar cells and the content of the secretory enzymes. The relationship between the histochemical reactivity and ultrastructural appearance of acinar cell granules and the organelles containing kallikrein, trypsin-like proteases and amylase seems much more important and functionally relevant. Morphological aspects of the intracellular transport and secretion of granules are discussed.We wish to thank The Wellcome Trust for a travel grant to attend the International Symposium on Vasopeptides (Florence, July, 1971) where this work was briefly reported.     

An electron microscopic study of retinal degeneration in Sprague-Dawley rats

Retinal degeneration in untreated, female Sprague-Dawley rats was studied by electron microscopy and horseradish peroxidase tracer technique. The degeneration appeared to have started at a very young age. The severity of the defect varied from a decrease of photoreceptor nuclei to total loss of receptor cells and the pigment epithelium. In mild degeneration some regions of the retinal pigment epithelium became bilayered and the basal plasma membrane became flattened or formed elaborate infoldings. Breaks in Bruch's membrane occurred in severe degeneration. Degeneration of the pigment epithelium allowed permeation of tracer material from the choroid into the retina.     

An electron microscopical study of the salivary glands of the tettigoniid, Homorochoryphus nitidulus

The fine structure of the salivary glands of the tettigoniid, Homorocoryphus nitidulus vicinus, has been studied by electron microscopy. Three main types of cell are present; the parietal cells, the zymogenic cells and the extracellular duct cells. Of these, the zymogenic cells are almost certainly the major secretory cells of the gland whereas the other two cell types exhibit features indicative of transporting epithelia, suggesting that they may be responsible for controlling the ion and water content of the saliva. This rôle in ion and water transport is further supported by the light histochemical demonstration of a ouabain-sensitive sodium-dependent ATPase in both the parietal cells and the cells of the extracellular ducts.     

Certain characteristic features of the lipolytic factor from rat submaxillary salivary glands

The aqueous extract of rat salivary submaxillary gland was found to contain three protein fractions activating the release of free fatty acids (FFA) and glycerol from rat epididymal adipose tissue in vitro. Physico-chemical investigations of these proteins demonstrated certain common features: all three fractions were albumins having a common isoelectric point, and their aqueous solutions absorbed light at the same wavelength. The use of lipolysis activators and inhibitors (theophylline, propranolol, insulin) for investigating their effects on FFA and glycerol release produced by these protein fractions explained the mechanism of the lipolytic action of the protein fractions from rat submaxillary glands.     

Supplemental studies on the method for electron microscopic demonstration of lipase in the pancreatic acinar cells of mice and rats

Summary The method for electron microscopic demonstration of lipase which was previously reported by the present authors was supplementally studied on the prefixation and substrate in normal animals as well as in animals with experimental pancreatitis.As for the fundamental techniques, no significant difference was observed between the concentrations of the glutaraldehyde for prefixation, neither the kinds of Tweens used, while a significant difference was observed between the duration of incubation. A longer incubation (16–18 hours) brought about larger end products, a shorter incubation (1–3 hours) smaller products.In the animals with experimental pancreatitis, the lipase activity observed in endoplasmic reticulum and Golgi apparatus was not changed as compared with the normal controls, while the activity in secretory granules and glandular lumen decreased. Furthermore, the lipase activity appeared in focal cytoplasmic degradation and around lipid droplets which were not found in the normal controls.