A tracer method to study unidirectional fluxes of lithium

Thellier, Michel; Hartmann, A.; Lassalles, Jean-Paul; Garrec, Jean-Pierre

doi:10.1016/0005-2736(80)90011-5

Cited by 11 publications

(7 citation statements)

References 5 publications

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“…Consequently, in contrast to tight epithelium [5,21,34,38], it seems that Li is not actively transported through the cells of the proximal tubule. On the other hand, some evidence has shown that lithium can diffuse widely through the mammalian proximal convoluted tubule [12,20,35].…”

Section: Discussionmentioning

confidence: 91%

Dependence of water movement on sodium transport in kidney proximal tubule: A microperfusion study substituting lithium for sodium

1981

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The relationship between water and sodium movements through the mammalian proximal convoluted tubule was investigated by substituting lithium for sodium. Proximal convoluted rat Kidney tubules were perfused in vivo with a Ringer solution containing 107 meq/liter lithium and 42 meq/liter sodium. Several micropunctures were made along the same nephron, and [3H] inulin, [14C] glucose, 22Na, osmolality, Na, Mg and Cl were determined on each sample. Measurements of 22Na showed that sodium and lithium diffusion rates were practically identical throughout the entire epithelium. A one- for-one exchange of sodium for lithium induced a negative transepithelial net flux of Na from plasma to lumen. However, despite this negative flux, a positive net water movement was measured from lumen to plasma. This movement was proportional both to glucose reabsorption and to the rise in the chloride concentration, two mechanisms known to be dependent on the transcellular movement of sodium. It was therefore concluded that the net water flux was a function of the unidirectional transcellular net flux of Na. Rabbit proximal convoluted tubules were perfused in vitro with solution containing 75 meq/liter Li and 75 meq/liter Na on both the luminal and peritubular sides. Under these conditions, the water reabsorption rate dropped to half its control value. Water movement was therefore a function of the external sodium concentration, which in turn probably regulates the intracellular Na concentration.

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Section: Discussionmentioning

confidence: 91%

Dependence of water movement on sodium transport in kidney proximal tubule: A microperfusion study substituting lithium for sodium

1981

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“…Furthermore, an oscillation of the Na+-influx accompanied the oscillation of the electric potential of the skin with a period of similar value, and the oscillations of the electric potential occurred with the separated epithelium as well as with the entire skin. Direct measurements of unidirectional fluxes of lithium, 'with stable isotopes 6Li and 7Li, have also shown us that Li is actively transported by the ion pump [34]. Other authors, with more indirect methods, have reached the same conclusion [24,26,401.…”

Section: Discussionmentioning

confidence: 83%

“…However, as we have shown with the stable Li-isotopes [8,34,36], Li § can pass through the skin from the internal to the external medium. When it is supplied to the external medium at a sufficient concentration (> 20-30mM), lithium is effective in inducing the oscillation.…”

Section: Discussionmentioning

confidence: 97%

Oscillation of the electric potential of frog skin under the effect of Li+: Experimental approach

Lassalles¹,

Hartmann²,

Theillier³

1980

J. Membrain Biol.

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When a frog skin is used to separate two compartments, and lithium is added to the external medium, transmembrane electric potential oscillations frequently occur. When no external current is imposed, sustained oscillations, with a period of about 10 min, are maintained for several hours. An oscillation of the Na+ influx accompanies the electric oscillation, though the two oscillations are out of phase to a greater or less extent. Theophyllin promotes a significant decrease in the mean electric potential of the skin, but it does not affect very much the characteristics of the oscillation. Important factors influencing the oscillation are temperature, permeability of the external membrane to lithium, and potassium concentration in the internal medium. No correlation can be detected between oscillation characteristics and skin area. This suggests that the oscillation is of a local nature, possibly originating at the cellular level. Occurrence of macroscopic oscillations implies coupling between local oscillators. Coupling between two epithelia has been studied under diverse conditions. The coupling is of an electrical nature: by varying the value of the coupling resistance, it is possible to control synchronization of the oscillations.

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“…The instrument's ability to image isotopes at a submicron resolution with high sensitivity is ideally suited to elemental localization and transport studies in biological systems under physiological and pathological conditions. Early studies in biological SIMS were from Galle's laboratory [31], and now biological ion microscopy has developed into a small international field [6,11,12,26,30,38,40,44,52,53]. Recent advances in SIMS technology have enhanced the biomedical applicability of ion microscopy by introducing instruments with improved spatial resolution [38] and molecular imaging capabilities [48].…”

Section: Introductionmentioning

confidence: 99%

Sample preparation of animal tissues and cell cultures for secondary ion mass spectrometry (SIMS) microscopy

Chandra

Morrison

1992

Biology of the Cell

108

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Sample preparation is a critical step in the elemental analysis of animal tissues and cell cultures with ion microscopy. Since live cells cannot be analyzed with ion microscopy, a careful sample fixation is necessary which preserves the native structural and chemical integrity of a specimen. The evaluation of morphological and chemical integrity of a fixed specimen is necessary before any physiological explanation of ion fluxes is interpreted based on ion microscopy. For diffusible ion localization studies, strict cryogenic procedures are recommended. Examples are shown for diffusible ion microanalysis in frozen-freeze-dried tissues and cell cultures. Ion microscopy studies of tightly bound elements/molecules may be conducted in chemically fixed and/or plastic embedded specimens. Since it is not generally known which elements/molecules are tightly bound to the tissue matrix, a confirmation of elemental distribution with cryogenic procedures is desirable. A recent approach of combining laser scanning confocal fluorescence microscopy and ion microscopy on the same frozen freeze-dried cell is also discussed for recognizing smaller cytoplasmic structures in ion microscopy images.

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A tracer method to study unidirectional fluxes of lithium

Cited by 11 publications

References 5 publications

Dependence of water movement on sodium transport in kidney proximal tubule: A microperfusion study substituting lithium for sodium

Dependence of water movement on sodium transport in kidney proximal tubule: A microperfusion study substituting lithium for sodium

Oscillation of the electric potential of frog skin under the effect of Li+: Experimental approach

Sample preparation of animal tissues and cell cultures for secondary ion mass spectrometry (SIMS) microscopy

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