Microprobe measurement of Na, K and Cl concentration profiles in epithelial cells and intercellular spaces of rabbit ileum

Nature ◽  
1978 ◽  
Vol 272 (5648) ◽  
pp. 70-73 ◽  
Author(s):  
BRIJ L. GUPTA ◽  
T. A. HALL ◽  
R. J. NAFTALIN
Keyword(s):  
Epithelial Cells ◽  
Concentration Profiles ◽  
Intercellular Spaces ◽  
Rabbit Ileum ◽  
Microprobe Measurement

Two calcium channels in basolateral membranes of rabbit ileal epithelial cells

1989 ◽  
Vol 257 (1) ◽  
pp. G86-G93
Author(s):  
F. R. Homaidan ◽  
M. Donowitz ◽  
G. A. Weiland ◽  
G. W. Sharp
Keyword(s):  
Epithelial Cells ◽  
Calcium Channels ◽  
Calcium Channel ◽  
Short Circuit ◽  
Short Circuit Current ◽  
The Other ◽  
Channel Blockers ◽  
Binding Studies ◽  
Rabbit Ileum ◽  
Basolateral Membranes

The actions of three different types of calcium channel blockers on short-circuit current (Isc) in rabbit ileum were studied. These included the phenylalkylamines, verapamil and (l)-desmethoxyverapamil (D888); the dihydropyridines, nifedipine and nitrendipine; and the benzothiazepine, diltiazem. All of the drugs decreased Isc, a change associated with increased Na and Cl absorption. Verapamil and D888 had the largest effects. The dihydropyridine, BAY K 8644, a calcium channel activator, increased Isc and decreased Na and Cl absorption, effects not inhibited by tetrodotoxin. The phenylalkylamines had an additional effect on Isc in the presence of a maximally inhibitory concentration of the dihydropyridines, suggesting the possibility of two distinct calcium channels, one of which is the L-type voltage-activated, dihydropyridine- and phenylalkylamine-sensitive channel, and the other is a channel only sensitive to phenylalkylamines but not to dihydropyridines. [3H]nitrendipine and [3H]D888 binding to an enriched preparation of basolateral membranes from ileal epithelial cells was characterized. Each ligand bound specifically and saturably to an apparently single population of high-affinity sites with [3H]D888 having three times as many binding sites as [3H]nitrendipine. [3H]nitrendipine binding was partially inhibited by verapamil and D888 and was increased by diltiazem; whereas [3H]D888 binding was inhibited completely by verapamil but only partially by nitrendipine and diltiazem. These transport and binding studies suggest the presence of two types of Ca2+ channels in ileal epithelial cells, one of which interacts with the dihydropyridines, the phenylalkylamines, and the benzothiazepines at three different sites and the other channel that only binds the phenylalkylamines.

scholarly journals MEMBRANE-COATING GRANULES OF KERATINIZING EPITHELIA

1965 ◽  
Vol 24 (2) ◽  
pp. 297-307 ◽  
Author(s):  
A. Gedeon Matoltsy ◽  
Paul F. Parakkal
Keyword(s):  
Electron Microscopy ◽  
Plasma Membrane ◽  
Epithelial Cells ◽  
Cell Envelope ◽  
Cell Periphery ◽  
Cell Surfaces ◽  
Intercellular Spaces ◽  
Cytoplasmic Granules ◽  
Coated Cell ◽  
Membrane Coating

The purpose of this study has been to obtain information on the development of the envelop of horny cells that resists the action of keratinolytic agents. Toward this end the epidermis, oral mucosa, and tongue epithelium of various vertebrates, as well as the isolated envelopes of horny cells, were examined by electron microscopy. It was found that small cytoplasmic granules (1,000 to 5,000 A) that develop within differentiating epithelial cells move toward the cell periphery, and after fusion with the plasma membrane, empty their contents into the intercellular spaces. The content of the granules spreads over the cell surfaces, and subsequently a thickened and coated cell envelope is formed that resists the action of keratinolytic agent. The membrane-coating granule is regarded as a specific differentiation product of the keratinizing epithelium. It contains numerous inner membranes and is assumed to engage in synthetic activities such as, perhaps, the formation of polysaccharides.

scholarly journals Studies on the Electrical Potential Profile across Rabbit Ileum

1971 ◽  
Vol 57 (6) ◽  
pp. 639-663 ◽  
Author(s):  
Richard C. Rose ◽  
Stanley G. Schultz
Keyword(s):  
Amino Acids ◽  
Brush Border ◽  
Electrical Potential ◽  
Metabolic Inhibitors ◽  
Electrical Potential Difference ◽  
Intercellular Spaces ◽  
Cell Interior ◽  
Rabbit Ileum ◽  
Lateral Intercellular Spaces ◽  
Rapid Replacement

When isolated strips of mucosal rabbit ileum are bathed by physiological electrolyte solution the electrical potential difference (PD) across the brush border (ψmc) averages 36 mv, cell interior negative. Rapid replacement of Na in the mucosal solution with less permeant cations, Tris or choline, results in an immediate hyperpolarization of ψmc. Conversely, replacement of choline in the mucosal solution with Na results in an abrupt depolarization of ψmc. These findings indicate that Na contributes to the conductance across the brush border. The presence of actively transported sugars or amino acids in the mucosal solution brings about a marked depolarization of ψmc and a smaller increase in the transmural PD (Δψms). It appears that the Na influx that is coupled to the influxes of amino acids and sugars is electrogenic and responsible for the depolarization of ψmc. Under control conditions Δψms can be attributed to the depolarization of ψmc together with the presence of a low resistance transepithelial shunt, possibly the lateral intercellular spaces. However, quantitatively similar effects of amino acids on ψmc are also seen in tissues poisoned with metabolic inhibitors or ouabain. Under these conditions Δψmc is much smaller than under control conditions. Thus, the depolarization of ψmc might not account for the entire Δψms, observed in nonpoisoned tissue. An additional electromotive force which is directly coupled to metabolic processes might contribute to the normal Δψms.

A Freeze-Etching Study on Experimental Murine Mastitis

1978 ◽  
Vol 15 (5) ◽  
pp. 638-648 ◽  
Author(s):  
K. Smith ◽  
R. L. Chandler
Keyword(s):  
Electron Microscopy ◽  
Epithelial Cells ◽  
Potential Barrier ◽  
Mammary Glands ◽  
Pathological Changes ◽  
Intercellular Spaces ◽  
Freeze Etching ◽  
Junctional Complexes ◽  
Acinar Lumen

Streptococcal mastitis was produced experimentally in mice inoculated by the intramammary route; freeze-etched preparations from the affected mammary glands were studied by electron microscopy. The inoculated cocci were seen free in the acinar lumen, within luminal phagocytes and within cells of the epithelium. No significant pathological changes were noted in the junctional complexes between secretory epithelial cells. The results were comparable to those obtained by ultrathin sectioning and indicated that, while cocci can transfer from the acinar lumen into the substance of the epithelium and towards a subepithelial location, the junctional complexes between epithelial cells present a potential barrier to movement through the intercellular spaces.

Analysis of contact-rehydration in terrestrial gastropods: absorption of 14C-inulin through the epithelium of the foot

1984 ◽  
Vol 111 (1) ◽  
pp. 75-80
Author(s):  
D. J. Prior ◽  
G. L. Uglem
Keyword(s):  
Electron Microscopy ◽  
Epithelial Cells ◽  
Filter Paper ◽  
Bulk Flow ◽  
Paracellular Pathway ◽  
Drinking Behaviour ◽  
Intercellular Spaces ◽  
Terrestrial Gastropods

Contact-rehydration in terrestrial slugs involves a specific drinking behaviour during which water is rapidly absorbed through the integument of the foot. When dehydrated slugs were placed on wet filter paper containing 14C-inulin, they displayed the characteristic drinking posture and absorbed both water and 14C-inulin. Samples of haemolymph from dehydrated slugs after 12 min of contact-rehydration contained about 6 micrograms of 14C-inulin 100 mg-1 of haemolymph (0.24 mmol l-1 14C-inulin in the substrate). The haemolymph of hydrated slugs however contained no detectable radioactivity after 12 min on the filter paper. Electron microscopy revealed that the intercellular spaces between the epithelial cells of the foot were reduced in dehydrated slugs, but were rapidly enlarged during contact-rehydration. It is concluded that contact-rehydration in terrestrial slugs is mediated by bulk flow of water through an epithelial paracellular pathway in the integument of the foot.

Development of intercellular junctions in the pulmonary epithelium of the foetal lamb

1978 ◽  
Vol 32 (1) ◽  
pp. 307-324
Author(s):  
E.E. Schneeberger ◽  
D.V. Walters ◽  
R.E. Olver
Keyword(s):  
Electron Microscopy ◽  
Epithelial Cells ◽  
Tight Junctions ◽  
Lung Development ◽  
Light And Electron Microscopy ◽  
Intercellular Junctions ◽  
Intercellular Spaces ◽  
Thin Sections ◽  
Epithelial Tight Junctions ◽  
Foetal Lamb

The integrity of epithelial tight junctions in foetal mammalian lungs is essential to maintain the unique ionic composition of lung liquid, and to prevent leakage of serum proteins into peripheral air spaces. In the present study the development of intercellular junctions of the lining epithelium of foetal lamb lungs during gestation was examined by light and electron microscopy. Both thin sections and freeze-fracture replicas were examined by electron microscopy. By 39 days of gestation, epithelial tight junctions consist of a minimum of 3.1 +/− 1.6 (s.D.) and a maximum of 5.8 +/− 2.0 discontinuous rows of particles and short segments of strands on P face ridges and in complementary E face grooves, while from 58 to 76 days they are composed of a network of 4.3 +/− 1.6 to 7.7 +/− 1.9 focally interrupted P face strands. Complementary replicas show that many of the discontinuities on the P face are due to separation of junctional particles on to the E face during fracturing, and not to an absence of junctional particles. From 76 days to term, epithelial tight junctions (exclusive of upper airway epithelium which was not examined) resemble those of adult lungs, and consist of a continuous network of 4.5 +/− 2.0 to 7.5 +/− 2.5 P face strands and complementary particle-free grooves. Permeability measurements, published elsewhere, indicate that the epithelium is functionally ‘tight’ from 69 days onwards. Tight junctions in peripheral air-space epithelium, therefore, are structurally continuous and functionally ‘tight’ early in foetal lung development, and form seals at one end of long, narrow intercellular spaces; these features may be important for coupled ion and water transport. When the bounding epithelial cells become flattened, these narrow intercellular spaces remain intact as a result of complex interdigitations of adjacent cell membranes. Desmosomes were present throughout gestation near the abluminal side of the tight junctions and occasionally near the base of the intercellular space. These junctions may serve to connect cells to each other at a time when tight junctions may be mechanically weak. In addition, gap junctions are associated with tight junctions from the glandular through the canalicular stages of lung development. They disappear by 120 days when the epithelial cells are differentiated.

scholarly journals ELECTRON MICROSCOPY OF ABSORPTION OF TRACER MATERIALS BY TOAD URINARY BLADDER EPITHELIUM

1965 ◽  
Vol 25 (2) ◽  
pp. 175-192 ◽  
Author(s):  
Jae Kwon Choi
Keyword(s):  
Electron Microscopy ◽  
Epithelial Cells ◽  
Urinary Bladder ◽  
Colloidal Particles ◽  
Intermediate Stage ◽  
Toad Urinary Bladder ◽  
Intercellular Spaces ◽  
Bladder Epithelium ◽  
Physiological Factors ◽  
Tracer Particles

The absorption of Thorotrast and saccharated iron oxide by the epithelium of the toad urinary bladder was studied by electron microscopy. Whether the toads were hydrated, dehydrated, or given Pitressin, no significant differences in transport of colloidal particles by epithelial cells were observed. This implies that these physiological factors had little effect on the transport of the tracer particles. Tracer particles were encountered in three types of epithelial cells which line the bladder lumen, but most frequently in the mitochondria-rich cells. Tracer materials were incorporated into the cytoplasm of epithelial cells after being adsorbed to the coating layer covering the luminal surface of the cells. In the intermediate stage (1 to 3 hours after introducing tracer) particles were present in small vesicles, tubules, and multivesicular bodies. In the later stages (up to 65 hours), the particles were more commonly seen to be densely packed within large membrane-bounded bodies which were often found near the Golgi region. These large bodies probably were formed by the fusion of small vesicles. Irrespective of the stages of absorption, no particles were found in the intercellular spaces or in the submucosa. Particles apparently did not penetrate the intercellular spaces of the epithelium beyond the level of the tight junction.

Effects of amiloride on the endolymphatic sac

1989 ◽  
Vol 103 (5) ◽  
pp. 466-470 ◽  
Author(s):  
M. Takumida ◽  
D. Bagger-Sjöbäck
Keyword(s):  
Epithelial Cells ◽  
Ion Exchange ◽  
Fluid Transport ◽  
Endolymphatic Hydrops ◽  
Endolymphatic Sac ◽  
Intercellular Spaces ◽  
Exchange System ◽  
Fluid Exchange ◽  
Apical Portion ◽  
Lateral Intercellular Spaces

AbstractThe effect of amiloride on the murine endolymphatic sac was investigated. The amiloride caused collapse of the lateral intercellular spaces in the endolymphatic sac epithelium and a subsequent mild endolymphatic hydrops. These changes indicated a decreased absorption of endolymph in the endolymphatic sac. Amiloride is known to inhibit the transcellular fluid transport without inducing any changes in the paracellular fluid transport. It is therefore suggested that amiloride specially inhibits the fluid and ion exchange in the apical portion of the epithelial cells resulting a decrease in transcellular fluid transport across the endolymphatic sac epithelium. The transcellular fluid transport seems to be one of the main mechanisms in the endolymphatic sac fluid exchange system.

scholarly journals The Fine Structure of the Bovine Wart

1966 ◽  
Vol 3 (6) ◽  
pp. 659-684 ◽  
Author(s):  
Yutaka Fujimoto ◽  
Carl Olson
Keyword(s):  
Fine Structure ◽  
Epithelial Cells ◽  
Light And Electron Microscopy ◽  
Stratum Granulosum ◽  
Intercellular Spaces ◽  
Proliferating Cells ◽  
Virus Like Particles ◽  
Naturally Occurring ◽  
Cytoplasmic Vacuolization ◽  
Viral Particles

The fine structure of 5 naturally occurring and 4 experimentally produced cases of bovine cutaneous fibropapillomatosis was compared to that of normal bovine skin with both light and electron microscopy. Both degenerative and proliferative changes were found in the affected epithelial cells and fibroblasts. Virus-like particles (approximately 40 m μ) were first seen in the nuclei of degenerating fibroblasts and later in the epithelium. The number of virus-like particles was always small and they were associated with aggregates of chromatin. They were most numerous in the stratum granulosum. The degenerative changes were aggregation and margination of chromatin in the nucleus. In addition, epithelial cells had cytoplasmic vacuolization, loss of tonofibrils, focal necrobiosis, increased electron opaque globules and dilatation of intercellular spaces with changes of desmosomes. When these changes were marked the cells could be recognized as “pale cells” by light microscopy and usually occurred in groups. Viral multiplication appeared confined to these degenerating cells and no viral particles could be found in the proliferating cells. The proliferating epithelial cells were increased in size. These changes were progressive in the developing fibropapilloma and could be categorized into stages of fibroplasia, immature fibropapilloma, mature fibropapilloma and regression.

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