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Digitale Medien

Selective blockage of cell membrane K conductance by an antisecretory agent in guinea-pig gallbladder epithelium (1989)

Wehner, Frank ; Winterhager, Joachim M. ; Petersen, Karl-Uwe

Springer

Pflügers Archiv 414 (1989), S. 331-339

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ISSN: 1432-2013

Schlagwort(e): HCO3 secretion ; Membrane potentials ; Cell membrane ion permeabilities ; Ouabain ; Prostaglandin E1 ; Loperamide

Quelle: Springer Online Journal Archives 1860-2000

Thema: Medizin

Notizen: Abstract Loperamide inhibits PGE1-induced electrogenic HCO3 secretion in guinea-pig gallbladder. Underlying changes in epithelial cell membrane properties were investgated using intracellular microelectrode techniques in vitro. In the absence of PGE1, mucosal loperamide (10−4 mol/l) reversibly depolarized both cell membranes by ∼ 6 mV. The apparent ratio of membrane resistances (R a/R b) remained unchanged and so did voltage responses to luminal Cl removal and Na reduction. The depolarizing response to elevation of luminal K concentration from 5 to 76 mmol/l was decreased from 13 to 8 mV. In the presence of 1 PGE1, the apical membrane is mainly permeable to Cl and HCO3. Under these conditions, loperamide reduced membrane potentials by ∼ 10 mV,R a/R b remaining constant at ∼ 0.4. Effects on voltage responses to changes in luminal Na or K concentration were unchanged. Responses to luminal Cl removal (transient depolarization) were greatly enhanced (from 22 to 42 mV) as predictable from the fall in K permeability that hinders Cl efflux from cell into lumen. Less marked but significant effects were obtained with 10−5 mol/l (mucosal side) and serosal loperamide (10−4 mol/l). We suggest that loperamide inhibits electrogenic HCO3 secretion by reducing apical membrane K permeability. The resulting depolarization diminishes the driving force for conductive anion efflux from cell into lumen. This conclusion is supported by the ability of luminal K elevation to mimick loperamide inhibition of the secretory flux of HCO3 (pH-stat experiments).

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF00584635

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Physical oceanography during METEOR cruise M31/2 (2013)

Hemleben, Christoph ; Wehner, Frank

PANGAEA

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Publikationsdatum: 2024-02-01

Schlagwort(e): Calculated; Conductivity; CTD, Neil Brown, Mark III B; CTD/Rosette; CTD-RO; Date/Time of event; Density, sigma, in situ; Density, sigma-theta (0); DEPTH, water; Elevation of event; Event label; JGOFS; Joint Global Ocean Flux Study; Latitude of event; Longitude of event; M31/2; M31/2-CTD-078_001; M31/2-CTD-080_001; M31/2-CTD-081_001; M31/2-CTD-081_002; M31/2-CTD-081_003; M31/2-CTD-081_004; M31/2-CTD-082_001; M31/2-CTD-084_001; M31/2-CTD-084_002; M31/2-CTD-087_001; M31/2-CTD-087_002; M31/2-CTD-091_001; M31/2-CTD-091_002; M31/2-CTD-092_001; M31/2-CTD-095_001; M31/2-CTD-102_001; Meteor (1986); Pressure, water; Salinity; Temperature, water; Temperature, water, potential

Materialart: Dataset

Format: text/tab-separated-values, 129364 data points

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