Abstract:In four epithelial cell systems (salivary gland, renal, urinary bladder, and sensory cells) cells are interconnected as far as much of their ion content is concerned. In the salivary gland and renal epithelia, all cells of the epithelium are interconnected; and communication between a given cell and any of its nearest neighbors is equally good. In the bladder and sensory epithelia, communication appears to be more restricted, manifesting itself in chains of connected cells in the former, and in small groups of… Show more
“…The mean coupling coefficient for the parotid cells (0.69 + 0.04) is higher than that reported in most other vertebrate epithelial systems (Gilula, Reeves & Steinbach, 1972;Johnson & Sheridan, 1971;Jamakosmanovic & Loewenstein, 1968;Loewenstein et al 1965). Only rat liver, in vitro, at 0*75-0*96 (Borek, Higashino & Loewenstein, 1969), Novikoff hepatoma, in vitro, at 0*9 (J. D. Sheridan & M. G. Hammer, unpublished observations), and pancreatic acinar cells (Petersen & Ueda, 1976) show higher values.…”
“…The mean coupling coefficient for the parotid cells (0.69 + 0.04) is higher than that reported in most other vertebrate epithelial systems (Gilula, Reeves & Steinbach, 1972;Johnson & Sheridan, 1971;Jamakosmanovic & Loewenstein, 1968;Loewenstein et al 1965). Only rat liver, in vitro, at 0*75-0*96 (Borek, Higashino & Loewenstein, 1969), Novikoff hepatoma, in vitro, at 0*9 (J. D. Sheridan & M. G. Hammer, unpublished observations), and pancreatic acinar cells (Petersen & Ueda, 1976) show higher values.…”
“…2 a illustrates an experiment in which an ion current is passed between the interior and exterior of a cell (I) of the rat liver surface, and the resulting resistive m e m b r a n e voltages are measured in this cell and simultaneously in an adjacent one (H). As in m a n y other types of epithelial cells (12,17), the resistance of the surface m e m b r a n e of the liver cell is quite ohmic: the m e m b r a n e shows no sign of electrical excitation and little or no rectification to a wide range of current. Most striking is the small difference in resistive membrane voltage in the two cells.…”
Section: Lack Of Communication Between Cancer Cellsmentioning
confidence: 78%
“…It consisted essentially of injecting a current of ions into a cell and determining what fraction of the current passes into an adjacent cell. The method is readily applicable to many cell systems and provides quantitative information (9,13,17). Liver cells were used for the study.…”
A B S T R A C TIntercellular communication was examined with intracellular electrical techniques in prim a r / a n d transplanted rat liver cancers. Normal liver cells communicate rather freely with each other through permeable junctional membranes. Cancer liver cells show no communication at all; their surface membrane is a strong barrier to diffusion all around the cell.Cancer cells induce alterations in membrane permeability in normal liver ceils; communication among the latter is markedly reduced when cancer cells grow near them.
I N T R O D U C T I O NEvidence for direct cell-to-cell communication is now availablc for a wide variety of epithelial tissues (12, 12 a, 17). At the surfaces of cell contact (junctional surfaces), the cell membranes in, at least, some of these tissues are normally so permeable that many cellular substances may diffuse rather freely from one cell interior to the next. The present series of papers deals with the question of whether cellular communication of this sort is involved in the control of tissue growth.It has long been evident that normal growth of tissues depends on some form of contact interaction between cells. Harmonious growth requires, among other things, that cells recognize each other and stop moving and growing atthe right place. Instructive, in this respect, is the movement of epidermal cells over a wound; the movement stops when the cells meet (10). Particularly instructive is the behavior of cells in tissue culture growing on glass surfaces. The cells stop moving and dividing when they establish contact with each other, and stop only then (1, 24). Some kind of signal appears to be transmitted from cell to cell upon contact. The question here, then, is whether diffusion of substances from cell interior to cell interior is involved in the signal transmission.A direct approach to the question seems hopeless until specific signal substances are identified. But one may try an indirect approach and see whether cellular communication is altered in situations of uncontrolled cellular growth. Here, we shall explore this point in cells showing the most notorious lack of growth control, cancer cells. Cancer cells, unlike normal ones, neither stop moving nor dividing upon cellular contact, as is seen particularly clearly in tissue culture (2, 5-7, 23a).
“…references 10,11,14), certain alternatives should be mentioned. The existence of a high resistance barrier surrounding the whole blastodisc is excluded since virtually no potential changes were recorded unless both current and recording micropipettes were intracellular.…”
Section: Discussionmentioning
confidence: 99%
“…certain nerve cells, cardiac, and visceral muscle cells) (1,2,4,5), but also between certain nonexcitable cells (e.g. glial cells and epithelial cells in insects, amphibians, and mammals) (8)(9)(10)(11)13). In all the cases cited above, electron microscopy has shown that the cells are connected by regions of specialized membrane apposition (e.g.…”
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