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Article
Effects of anions and/or cell volume on the permeance of an apical water pathway induced by Hg in toad skin epithelium
Hg compounds block membrane transport units behaving as water channels. Here we show that Hg induces an apical water pathway in toad skins pretreated with 10−3 M CH3ClHg or HgCl2, added to the outer bathing mediu...
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Article
High [K+] alters the stimulus-hydrosmotic response coupling in toad bladder
Substitution of K+ for Na+ in the Ringer solution bathing the inner surface of toad urinary bladders (Bufo marinus) had no effect on basal water permeability but significantly altered the stimulus-hydrosmotic res...
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Article
Cellular and membrane events involved in the K-induced increase in water permeability of toad skin
Exposure of the inner surface of toad skin (Bufo marinus) to high [K+] resulted in a marked (up to 7-fold) increase in water permeability (P f) that was more marked in KCl-Ringer than in K2SO4-Ringer. Although hi...
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Article
Quercetin enhances water transport in toad bladder
A highly significant enhancement of the hydrosomotic actions both of vasopressin and of exogenous cAMP was seen in the presence of quercetin. The hypothesis is advanced that quercetin affects the intracellular...
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Article
Vanadate blocks cyclic AMP-induced Stimulation of sodium and water transport in amphibian epithelia
INTEREST in the biological effects of vanadium has grown particularly since Cantley et al.1 identified vanadate as a potent inhibitor of (Na+ + K+) ATPase and Balfour et al.2 reported its striking natriuretic and...
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Article
Inhibitory and stimulatory effects of amiloride analogues on sodium transport in frog skin
Effects of amiloride analogues on Na transport were studied in isolated skins of the frogRana ridibunda. The pattern of structure-activity relationship of these compounds showed that both the −NH2 group at positi...
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Article
Sidedness of the inhibitory effects of diamide on Na and water transport in amphibian skin
Diamide, a thiol-oxidizing agent, blocks cAMP-mediated stimulation of Na and water transport when added to the outer solution bathing frog skin. No inhibition was found with diamide in the inner solution. Thes...
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Article
Cytochalasin B and water transport
A morpho-functional study of the effects of cytochalasin B (CB) on Na and water transport was made in amphibian epithelia. The functional studies confirmed the dissociation of the natriferic and hydrosmotic ef...
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Article
Towards a molecular definition of mechanisms and pathways of membrane transport
Collectively, all the conceptual and technological approaches briefly reviewed in this note share a common denominator: the tendency towards a molecular definition of mechanisms and pathways of transport. This...
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Article
Vasopressin-like effects of psychotropic drugs in amphibian epithelia
Amphibian epithelia have been used as models for studying the effects of psychotropic drugs on membrane transport. Several of these agents added to the internal or to the external media, at concentrations grea...
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Article
Particle aggregates in plasma and intracellular membranes of toad bladder (granular cell)
Freeze-fracture of granular cells of toad urinary bladder (Bufo marinus) reveals the presence, hitherto undescribed, of intramembranous particle aggregates in intracytoplasmic structures (tubules, vacuoles and ve...
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Article
Effects of Ag+ on frog skin: Interactions with oxytocin, amiloride and ouabain
Different biological effects of Ag+ (10−4 M) were found depending on its presence in the outer or the inner solution bathing the frog skin. A marked increase in the electrical conductance and an interference with...
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Article
A comparative study of the effects of norepinephrine and vasopressin on Na transport and O2 consumption in frog skin
Experiments were designed to compare the effects of two hormones-vasopressin and norepinephrine-on the energetics of Na transport in frog skin. Simultaneous measurements of O2 consumption and net Na flux were per...
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Article
Patterns of membrane organization in toad bladder epithelium: A freeze-fracture study
Two cell-types of toad bladder epithelium show uncommon plasma membrane organization in freeze-fractured specimens. One type, the granular cell, contains a plasma membrane in which the A-face is poorly particu...
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Article
Lanthanides and amphibian epithelia: Block of the hormone-induced stimulation of sodium and water transport
L'addition de lanthanides au milieu baignant la surface interne (séreuse) des épithélia d'amphibien provoque une inhibition de l'effet hydrosmotique et natriférique de l'ocytocine, de la nor-épinéphrine et de ...
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Article
Blockade of the hydrosmotic effect of vasopressin by cytochalasin B
La cytochalasine B dissocie les effets hydrosmotique et natriférique de la Pitressine sur la vessie de crapaud, en bloquant le transport d'eau sans pour autant modifier la stimulation du transport de sodium. L...
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Article
Effects of diphenylhydantoin on transport processes in frog skin (Rana ridibunda)
La diphénylhydantoïne agit sur la face externe de la peau de grenouille en provoquant une augmentation de la différence de potentiel et du courant de court circuit. L'effet est rapide, soutenu et réversible. D...
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Article
Optical method for measuring water flow with automatic recording
Une méthode optique d'enregistrement automatique de flux d'eau à travers des membranes biologiques et synthétiques est décrite. Le mouvement d'un ménisque à l'aide d'un dispositif photosensible, sans interfére...
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Article
Etude du métabolisme de l'aldostérone dans un cas de diabète insipide néphrogénique congénital
Extract: We have found repeatedly low or low-normal levels of aldosterone excretion in the urine of a boy presenting at birth with vasopressin-resistant diabetes insipidus. The only renal disorder was a lack o...
