Effects of internal and external pH on amiloride-blockable Na transport across toad urinary bladder vesicles

Journal Article · Tue Jan 01 04:00:00 EST 1985 · J. Membr. Biol.; (United States)

DOI:https://doi.org/10.1007/BF01870700· OSTI ID:6255901

Garty, H; Civan, E D; Civan, M M

The authors have examined the effect of internal and external pH on Na+ transport across toad bladder membrane vesicles. Of the total SSNa uptake measured 0.5-2.0 min after introducing tracer, 80 +/- 4% (mean +/- SE, n = 9) is blocked by the diuretic with a KI of 2 X 10(-8) M. Thus, this amiloride-sensitive flux is mediated by the apical sodium-selective channels. Varying the internal (cytosolic) pH over the physiologic range 7.0-8.0 had no effect on sodium transport; this result suggests that variation of intracellular pH in vivo has no direct apical effect on modulating sodium uptake. On the other hand, SSNa was directly and monotonically dependent on external pH. External acidification also reduced the amiloride-sensitive efflux across the walls of the vesicles. This inhibition of 22Na efflux was noted at external Na concentrations of both 0.2 microM and 53 mM. These results are different from those reported with whole toad bladder. A number of possible bases for these differences are considered and discussed. They suggest that the natriferic response induced by mucosal acidification of whole toad urinary bladder appears to operate indirectly through one or more factors, presumably cytosolic, present in whole cells and absent from the vesicles.

• Research Organization: Weizmann Institute of Science, Rehovot, Israel
• OSTI ID: 6255901
• Journal Information: J. Membr. Biol.; (United States), Journal Name: J. Membr. Biol.; (United States) Vol. 1; ISSN JMBBB
• Country of Publication: United States
• Language: English

Related Subjects

551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALKALI METAL COMPOUNDS
ALKALI METAL ISOTOPES
AMPHIBIANS
ANIMALS
AQUATIC ORGANISMS
BARYONS
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BIOLOGICAL EFFECTS
BLADDER
BODY
CATIONS
CHARGED PARTICLES
ELEMENTARY PARTICLES
FERMIONS
HADRONS
IONS
ISOTOPES
KINETICS
LIGHT NUCLEI
MEMBRANE TRANSPORT
NUCLEI
NUCLEONS
ODD-ODD NUCLEI
ORGANS
PH VALUE
PROTONS
RADIOISOTOPES
SODIUM 22
SODIUM COMPOUNDS
SODIUM ISOTOPES
TOADS
URINARY TRACT
VERTEBRATES
YEARS LIVING RADIOISOTOPES