Measurement of K/sup +/ conductance in gastric vesicles from secreting stomach
Specific inhibitors were used to identify two components of /sup 86/Rb/sup +/ uptake in vesicles obtained from secreting rabbit stomachs. Rb/sup +/ transport was measured in vesicles as trace /sup 86/Rb/sup +/ uptake following removal of external K/sup +/ from vesicles equilibrated in potassium gluconate. /sup 86/Rb)2= uptake mediated by the gastric H/sup +/K/sup +/-ATPase was identified by sensitivity to vanadate, ATP and pyridyl (1,2a) imidazole (SCH28080). In contrast, /sup 86/Rb/sup +/ influx through a K/sup +/ conductance mechanism was inhibited by the protonophore (TCS) induced collapse of the K/sup +/ diffusion potential. K/sup +/ conductance sensitivity to quinine and the K/sup +/ channel blocker bis-Guanidinium (bis G-8) were demonstrated by inhibition of a K/sup +/ induced chase of intravesicular /sup 86/Rb/sup +/ previously loaded by /sup 86/Rb/sup +//K/sup +/ exchange in the presence of 2 ..mu..M SCH28080. The K/sup +/ conductance is Ba/sup 2 +/ and apamine insensitive and exhibits a monovalent cation specificity of Rb > Kapprox. = Cs >> Na, Li. KCl dependent H/sup +/ transport exhibited complete sensitivity to the H/sup +/, K/sup +/-ATPase inhibitors SCH28080 and vanadate. The measurements of Rb/sup +/ pathways distinctive for the H/sup +/, K/sup +/-ATPase and a K/sup +/ conductance support previous suggestions of a functional linkage between the H/sup +/, K/sup +/-ATPase and a K/sup +/ conductance in vesicles, obtained from stimulated stomach. The experimental discrimination between the two Rb/sup +/ pathways suggests that a separate mechanism is utilized for each transport pathway.
- Research Organization:
- Wadsworth V.A. Hospital, Los Angeles, CA
- OSTI ID:
- 7164225
- Report Number(s):
- CONF-8606151-; TRN: 87-004055
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:6; Conference: 76. annual meeting of the Federation of American Society for Experimental Biology, Washington, DC, USA, 8 Jun 1986
- Country of Publication:
- United States
- Language:
- English
Similar Records
Calcium and proton transport in membrane vesicles from barley roots
K-Cl transport systems in rabbit renal basolateral membrane vesicles
Related Subjects
ATP-ASE
ENZYME ACTIVITY
POTASSIUM COMPOUNDS
MEMBRANE TRANSPORT
RUBIDIUM
BIOLOGICAL PATHWAYS
ENZYME INHIBITORS
RUBIDIUM 86
STOMACH
ACID ANHYDRASES
ALKALI METAL COMPOUNDS
ALKALI METAL ISOTOPES
ALKALI METALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
ELEMENTS
ENZYMES
GASTROINTESTINAL TRACT
HYDROLASES
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
METALS
MINUTES LIVING RADIOISOTOPES
NUCLEI
ODD-ODD NUCLEI
ORGANS
PHOSPHOHYDROLASES
RADIOISOTOPES
RUBIDIUM ISOTOPES
560162* - Radionuclide Effects
Kinetics
& Toxicology- Animals
Plants
Microorganisms
& Cells