Biomedical subjects
Publications and source records attributed to K Unsicker.
Actin and myosin were located in astrocytes, marginal glial and ependymal cells in rat diencephalon by using antibodies against highly purified chicken gizzard actin and myosin. On the basis of these findings it is suggested that glial cell motility in vovo and in vitro is due to the presence of an intracellular actin/myosin system.
Antibodies against actin and myosin from smooth muscle, which may react with contractile elements from both muscular and muscle-like cells, were applied to fresh frozen sections of adult guinea-pig testis. Sections stained with an antibody against pectoralis (striated) muscle myosin or with non-immune globulin were used for controls. Peritubular cells of the lamina propria surrounding seminiferous tubulus contained large amounts of actin and myosin as judged by the intensity of immunofluorescence. Sertoli cells did not stain with the antibodies. Our results support the concept of peritubular cells being the critical force for the contractility of seminiferous tubules.
The interactions between nerve fibres from para- and orthosympathetic ganglia and adreno-cortical and -medullary cells were studied in joint cultures using explanted guinea-pig ciliary and sympathetic chain ganglia and enzyme-dispersed rat adrenal gland cells. Nerve fibres from both para- and orthosympathetic ganglia made only transitory contact with cortical cells, but consistently formed associations with isolated chromaffin cells which lasted for up to 10 days. Contacts between axons and chromaffin cells often showed particularly large varicosities and frequently withstood severe tests of durability from pulls of the fibre or the cell or both. By correlating phase contrast and catecholamine histochemistry (Falck-Hillarp method) it was shown that sympathetic fibres forming long-lasting contacts with chromaffin cells were adrenergic. The functional implications of the ability of autonomic nerves to distinguish between adreno-cortical and -medullary cells and the lack of specificity shown by the para- and orthosympathetic neurons during formation of long-lasting associations with chromaffin cells are discussed.
Explants and enzyme-dispersed cells of adrenal medulla from 10-12 day old rats were studied in culture for up to 3 weeks. Adrenomedullary chromaffin cells, nerve cells and satellite cells were clearly discernible. The nerve cells were few in number and did not show catecholaminespecific fluorescence. Chromaffin cells stored catecholamines, as judged by the Falck and Hillarp method, in varying amounts decreasing with age of the cultures and the distance from the explants. Exocytosis profiles observed with the electron microscope suggested that cultured chromaffin cells also released catecholamines. Moreover, the cells formed processes and frequently migrated into the outgrowth. After 6 days in culture, the great majority of chromaffin cells stored noradrenaline as revealed by electron microscopy with few adrenaline-storing cells being visible. Granular vesicles (approximately 80-240 nm in diameter) with cores of different electron densities were occasionally present in the same cell suggesting the occurrence of mixtures of primary and secondary amines. Apart from "chromaffin" granules, small clear and dense-cored vesicles (approximately 40-60 nm) were found both in the somata and cell processes. Chromaffin cells and their processes were often closely apposed and occasionally formed specialized attachment zones. As a whole, chromaffin cells in culture resembled small granule-containing cells in sympathetic ganglia. 0.5 mM dbcAMP prevented dedifferentiation of chromaffin cells as judged by the lack of processes, the size and amount of "chromaffin" granules and the high number of adrenaline-storing cells present after 6 days in culture. NGF caused a striking increase in the number of axons growing out from explants.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Lamellated sensory nerve endings were observed in the adrenal gland of guinea-pigs located at the corticomedullary junction close to venous blood vessels. We suggest that they form the afferents of a system contributing to a local regulation of adrenal blood flow.
The effects of various concentrations of 6-hydroxydopamine (6-OHDA) on rat adrenocortical cells in tissue culture were studied with phase contrast and electron microscopy. With 40 mg/l of 6-OHDA the first signs of alteration as revealed by microcinematography appeared in isolated cortical cells as early as 15 min after addition of the drug. There was a cessation of movement of cell organelles and an immobilisation of membrane undulations followed by the development of dark inclusion bodies. The cells underwent increasing shrinkage and collapsed by 1 1/2 h. Chromaffin cells were not affected until 45 min after exposure to the drug and neurons were the most resistant population. However 6 1/2 h after application of the drug most cells in the culture were dead. 6-OHDA applied in different doses and to adrenal explants did not alter the sequence of events. Ultrastructurally cortex cells underwent damage alone two lines: they either showed lytic changes or developed various types of dense bodies before reaching the lytic stage. Treatment of cortical cells with 40 mg/l 5-or 6-OHDA followed by exposure to buffered 2% glyoxylic acid and heat did not produce a fluorescence within the cells. Microspectrofluorimetry on amine models with noradrenaline, 5- and 6-OHDA revealed that neither 5-nor 6-OHDA are capable to form a fluorophore with glyoxylic acid.
6-hydroxydopamine (6-OHDA) was shown to cause ultrastructural changes in adrenocortical cells of lizards and rats. These changes comprised the formation of dense bodies with lamellar and crystalloid patterns, a decrease in the number of mitochondria and structural alterations of mitochondria. Alterations in adrenomedullary cells were not affected as a rule. Only in young animals did 6-OHDA cause deposits of an electron-dense material in medullary cells. An attempt was made to obtain information on amine uptake into cortical cells using the Falck-Hillarp technique to analyse the in-vivo and in-vitro uptake of noradrenaline (NA) into the adrenal cortex in adult rats. Extraneuronal uptake into heart and spleen was studied as well. Our results suggest that NA is taken up into cortical cells, particularly into nuclei, after exposure to 10(-4) gm/ml in-vitro indicating that uptake of 6-OHDA is also likely. Investigations using labelled 6-OHDA is also likely. Investigations using labelled 6-OHDA are required for further elucidating its extraneuronal uptake.
Explants of rat adrenal medulla were grown in tissue culture. The effects of various doses of dbcAMP ranging from 0.001 mM up to 1 mM and equimolar amounts of theophylline were recorded by phase contrast optics and catecholamine histochemistry (glyoxylic acid method) over six days. There was a dose-dependent inhibition of the normally occurring outgrowth of Schwann cells, "chromaffin" cells and axons from the explants. Maintenance of glyoxylic acid-induced fluorescence in "chromaffin" cells was dose-dependent, too. Since theophylline is known to enhance intracellular levels of cAMP only, these effects are probably due to the action of cAMP. cAMP obviously maintains the degree of differentiation of chromaffin cells. Thus it could be argued that a certain degree of dedifferentiation is a prerequisite for the formation of axons from these cells.
Chromaffin, small granule-containing (SGC)-cells, neurons and the innervation of these cells was studied in the adrenal gland of three species of reptiles (Testudo graeca, Lacerta dugesi, Natrix natrix). 1. After fixation with glutaraldehyde and osmium-tetroxide adrenaline (A)- and noradrenaline (NA)-storing cells can be distinguished by means of the different electron density of their granules: A-granules are moderately electron-dense, while NA-granules show a core of high electron density. The unusually high electron density of a few A-granules in Testudo occasionally required viewing of unstained sections which facilitated the discrimination of the two cell types in this species. In all species studied NA-granules display a remarkable polymorphism which is most pronounced in the tortoise. In this species A-granules are polymorphic, too. Both types of granules show wide variations in size, which are particularly great in the tortoise. This species also exhibits the largest average sizes for A-granules (285 nm), and NA-granules (354 nm). The corresponding parameters for Lacerta and Natrix, are 255 and 179 nm for A- and 323 and 304 nm for NA-granules, respectively. The rough ER in A-cells of the tortoise regularly occurs in the form of circular dilations ('ergastosomes', Kanerva and Hervonen, 1973). Mitochondria sometimes contain longitudinal cristae with a crystalloid internal pattern. Large dense bodies which incorporate granules are abundant in NA-cells. Smaller dense bodies containing a few dense patches and membranes are present in both A- and NA-cells. Intermediate stages between dense bodies and what appear to be A- or NA-granules (if the latter have lost some of their amine-content) are frequently observed.
In the adrenal gland of Göttingen miniature pigs adrenaline- and noradrenaline-storing cells showed follicular and reticular arrangements, which were not observed in the domesticated form (German land race) of Sus scrofa. Chromaffin cells could contain vacuoles, which were sometimes connected with follicles and filled with a material indistinguishable from that in follicles. Coated and smooth vesicles with contents of various electron densities were particularly abundant around vacuoles and Golgi areas, which were often found to be closely associated. Chromaffin cells were unconspicious with respect to other ultrastructural details. A comparison was made between this mode of arrangement and that seen after intense stimulation of the adrenal medulla using insulin, reserpine, or vinblastine. The possible significance of this particular pattern of arrangement of chromaffin cells is discussed.
The arrangement and fine structure of peritubular myoid cells was studied in the testes of three species of reptiles (Lacerta dugesi, Testudo graeca and Natrix natrix) during two short periods of the seasonal cycle (European spring and autumn) and correlated with some ultrastructural properties of Leydig cells. The lamina propria consists of myoid cells, fibroblasts and non-cellular components comprising collageneous and non-striated microfibrils. Both components are arranged in alternating layers surrounding seminiferous tubules. In spring the lamina propria of lacertilian testis shows 1-5 layers of myoid cells which are rich in 50-70 A filaments and exhibit plasmalemmal and intracellular dense patches, smooth vesicles along the cell membrane and a concentration of organelles in a juxtanuclear position. Leydig cells are rich in smooth ER profiles and have few lipid droplets. In atumumn most myoid cells are replaced by fibroblast-like elements. Leydig cells display large numbers of lipid droplets and dense bodies, but only small amounts of agranular ER. Similar changes are noted in Leydig cells of Testudo and Natrix. However, in these species the boundary tissue of seminiferous tubules fails to show significant alterations comparing spring and autumn animals. In both species the lamina propria exhibits a few fibroblast-like cells interspersed among myoid cells.
The innervation of the male genital tract and kidney in three anuran species was studied by the fluorescence histochemical method of Falck-Hillarp for the demonstration of monoamines whose identity was secured by thin-layer chromatography, and by electron microscopy including administration of 5- or 6- hydroxydopamine (5- and 6-ODHA). The genital tract comprises testis, intra- and extratesticular and intrarenal seminal efferent ducts, Bidder's canal, renal dorsal transverse ducts, and ureter. In addition--depending on the species studied--renal corpuscles and the various portions of uriniferous tubules may be involved in sperm transport. 1. Adrenaline is the main transmitter in nerves supplying the male genital tract and kidney. Only in Xenopus is it possible to demonstrate the presence of noradrenaline, which was confirmed in the chromatographic analysis. No obvious changes are observed with regard to the distribution, amount, and fluorescence intensity of adrenergic fibers and their susceptibility towards 5- and 6-OHDA when comparing animals killed in late autumn and winter, or in late spring, respectively. Non-adrenergic nerve fibers have not been observed. 2. The adrenergic innervation in the testis is only scarce and confined to blood vessels. Neuro-endocrine contacts on Leydig cells are not established. The gonadal ducts and the specific (i.e. non-vascular) are intratesticular smooth muscle cells in Xenopus are not innervated. 3. Apart from the uriniferous tubules (see below), only the ureter receives an adrenergic innervation which, however, is scarce even around the time of spermiation. Bundles of non-terminal and terminal axons are seen running contiguous to the superficial bundles of smooth muscle or smooth muscle-like cells. Neuromuscular relationships comprise synapses at distances of 2000-5--- A, but no close contacts. In the seminal vesicle of Rana the same mode of apposition of adrenergic terminals to muscle cells is observed. In addition, a direct innervation of the epithelium is seen in a few instances. 4. In the kidney the renal arteries, afferent arterioles, and the main branches of the kidney the renal arteries, afferent arterioles, and the main branches of the portal veins are supplied by a dense plexus of adrenergic nerves. Small groups of intensely fluorescent cells are found in the walls of the renal portal veins and veins proper. The density of the arteriolar plexus is more pronounced in Rana and Bufo than in Xenopus. In Rana and Bufo the arteriolar innervation comprises terminals at "ordinary" smooth musculature with membrane-to-membrane appositions, as well as contacts at a distance of 800 to 4000 A on juxtaglomerular epitheloid cells...