Ba2+-inhibitable /sup 86/Rb+ fluxes across membranes of vesicles from toad urinary bladder

Journal Article · Thu Jan 01 04:00:00 EST 1987 · J. Membr. Biol.; (United States)

DOI:https://doi.org/10.1007/BF01871229· OSTI ID:5356241

Garty, H; Civan, M M

/sup 86/Rb+ fluxes have been measured in suspensions of vesicles prepared from the epithelium of toad urinary bladder. A readily measurable barium-sensitive, ouabain-insensitive component has been identified; the concentration of external Ba2+ required for half-maximal inhibition was 0.6 mM. The effects of externally added cations on /sup 86/Rb+ influx and efflux have established that this pathway is conductive, with a selectivity for K+, Rb+ and Cs+ over Na+ and Li+. The Rb+ uptake is inversely dependent on external pH, but not significantly affected by internal Ca2+ or external amiloride, quinine, quinidine or lidocaine. It is likely, albeit not yet certain, that the conductive Rb+ pathway is incorporated in basolateral vesicles oriented right-side-out. It is also not yet clear whether this pathway comprises the principle basolateral K+ channel in vivo, and that its properties have been unchanged during the preparative procedures. Subject to these caveats, the data suggest that the inhibition by quinidine of Na+ transport across toad bladder does not arise primarily from membrane depolarization produced by a direct blockage of the basolateral channels. It now seems more likely that the quinidine-induced elevation of intracellular Ca2+ activity directly blocks apical Na+ entry.

• Research Organization: Weizmann Institute of Science, Rehovot (Israel)
• OSTI ID: 5356241
• Journal Information: J. Membr. Biol.; (United States), Journal Name: J. Membr. Biol.; (United States) Vol. 99:2; ISSN JMBBB
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALKALI METAL ISOTOPES
ALKALINE EARTH METAL COMPOUNDS
ALKALINE EARTH METALS
AMPHIBIANS
ANIMAL TISSUES
ANIMALS
AQUATIC ORGANISMS
BARIUM
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL EFFECTS
BIOLOGICAL PATHWAYS
BLADDER
BODY
CALCIUM COMPOUNDS
CARBOHYDRATES
CARDIAC GLYCOSIDES
CARDIOTONICS
CARDIOVASCULAR AGENTS
CATIONS
CELL CONSTITUENTS
CELL MEMBRANES
CHARGED PARTICLES
DAYS LIVING RADIOISOTOPES
DRUGS
ELEMENTS
EPITHELIUM
FROGS
GLYCOSIDES
INHIBITION
INTERMEDIATE MASS NUCLEI
IONS
ISOMERIC TRANSITION ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
MEMBRANE TRANSPORT
MEMBRANES
METALS
MINUTES LIVING RADIOISOTOPES
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANS
OUABAIN
RADIOISOTOPES
RUBIDIUM 86
RUBIDIUM ISOTOPES
STROPHANTHINS
TISSUES
TRACER TECHNIQUES
URINARY TRACT
VERTEBRATES