Summary
Basal cells of the bladder epithelium ofBufo marinus have been found heterogenous and consist of microfilament-rich cells (MFR-cell) and undifferentiated cells (Un-cell). The MFR-cell, which represents approximately 20% of the epithelial cell population, lies between the epithelial layer lining the urinary space and the basement membrane; it extends under several epithelial cells by processes of varying widths and lengths which contact, via desmosomes, other MFR-cells, as well as cells in the superficial layer, i.e., granular and mitochondria-rich cells. The cytoplasm of MFR-cell is filled with intermediate filaments arranged in bundles which run parallel to the plane of the epithelium and no dense granules, typical of granular cells, have been detected. Strong immunofluorescence for actin is associated with cells which occupy the same basal position as MFR-cells. Undifferentiated cells have no contact via desmosomes with adjacent cells and their cytoplasm is filled with free ribosomes; they lack bundles of intermediate filaments and posses no specialized organelles.
After a 4-hr pulse of3H-thymidine, 1.5% of epithelial cells incorporate thymidine into nuclear DNA, out of which 3/4 are basally 1/4 are apically located. Identification of cell types by electron microscopy reveals that ∼10% of undifferentiated basal cells are labeled, whereas less than 0.1% of granular cells and no MFR-cells incorporate3H-thymidine into DNA. When dissociated from the epithelium and separated by isopycnic centrifugation, MFR-cells possess a mean buoyant density of approximately 1.025, cosediment with mitochondria-rich cells and exhibit a strong immunofluorescence for actin. The function of MFR-cells remains unknown; however, they may play a role in cell coupling and responses to hormonal and physical factors.
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References
Brown, J.A., Jr., Scott, W.N. 1976. Aldosterone induces the synthesis of mRNA in mucosal cells of the toad's urinary bladder.Physiologis (Abstr.) 19:141
Choi, J.K. 1963. The fine structure of the urinary bladder of the toad,Bufo marinus.J. Cell Biol. 16:53
DiBona, D.R., Civan, M.M. 1972. Clarification of the intercellular space phenomenon in toad urinary bladder.J. Membrane Biol. 7:267
Francke, W.W., Schmid, E., Osborn, M., Weber, K. 1978. Different intermediate-sized filaments distinguished by immunofluorescence microscopy.Proc. Nat. Acad. Sci. USA 75:5034
Jockusch, B., Kellin, K.H., Meyer, R.M., Burger, M.M. 1978. An efficient method to produce specific anti-actin.Histochemistry 55:177
Kachadorian, W.A., Wade, J.B., Discala, V.A. 1975. Vasopressin: induced structural change in toad bladder luminal membrane.Science 190:67
Kraehenbuhl, J.P. 1977. Dispersed mammary gland epithelial cells. I. Isolation and separation procedures.J. Cell Biol. 72:406
Kraehenbuhl, J.P., Jamieson, J.D. 1977. Enzyme-labeled antibody markers for electron microscopy.In: Methods in Immunolgy and Immunochemistry. C.A. Williams and M.W. Chase, editor. Vol. 5, pp. 482–495. Academic Press, New York
Lefèvre, M.E., Reincke, U., Arbas, R., Gennaro, J.F. 1973. Lymphoid cells in the turtle bladder.Anat. Rec. 176:111
List, J.H. 1887. Ueber einzellige Drüsen (Becherzellen) im Blasenepithel der Amphibien.Arch. Mikr. Anat. 29:147
Loewenstein, W.R., Socolar, S.J., Higashino, S., Kano, Y., Davidson, N. 1965. Intercellular communication: Renal, urinary, bladder, sensory and salivary gland cells.Science 149:295
Payton, B.W., Bennet, M.V.L., Pappas, G.W. 1969. Permeability and structure of junctional membranes at an electronic synapse.Science 166:1641
Peachey, L.D., Rasmussen, H. 1961. Structure of the toad's urinary bladder correlated to its physiology.J. Biophys. Biochem. Cytol. 10:529
Rossier, M., Rossier, B., Pfeiffer, J., Kraehenbuhl, J.P. 1979. Isolation and separation of toad bladder epithelial cells.J. Membrane Biol. 48:141
Sapirstein, V.S., Scott, W.N. 1975. Binding of aldosterone by mitochondria-rich cells of the toad urinary bladder.Nature (London) 257:241
Scott, W.N., Sapirstein, V.S. 1974. Partition of tissue functions in epithelia: Localization of enzymes in “mitochondria-rich” cells of toad urinary bladder.Science 184:797
Scott, W.N., Sapirstein, V.S. 1975. Identification of aldosterone induced proteins in the toad's urinary bladder.Proc. Nat. Acad. Sci. USA 72:4056
Spinelli, F., Grosso, A., de Sousa, R.C. 1975. The hydroosmotic effect of vasopressin, a scanning electronmicroscope study.J. Membrane Biol. 23:139
Strum, J.M., Danon, D. 1974. Fine structure of the urinary bladder of the bullfrog (Rana catesbiana)Anat. Rec. 178:15
Voûte, C.L., Hänni, S., Ammann, E. 1972. Aldosterone induced morphological changes in amphibian epitheliain vivo.J. Steroid Biochem. 3:161
Wade, J.B. 1978. Membrane structural specialization of the toad urinary bladder revealed by the freeze-fracture technique. III. Location, structure and vasopressin dependence of intramembrane particle arrays.J. Membrane Biol. (in press)
Walser, M., Butler, S.E., Hammond, V. 1969. Reversible stimulation of Na+ transport in the toad bladder by stretch.J. Clin. Invest. 48:1714
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Kraehenbuhl, J.P., Pfeiffer, J., Rossier, M. et al. Microfilament-rich cells in the toad bladder epithelium. J. Membrain Biol. 48, 167–180 (1979). https://doi.org/10.1007/BF01872857
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DOI: https://doi.org/10.1007/BF01872857