Dihydroxy bile salt-induced secretion of rubidium ion across the rabbit distal colon

Journal Article · Wed Apr 01 04:00:00 EST 1987 · Am. J. Physiol.; (United States)

OSTI ID:5879277

Freel, R W

Possible mechanisms of dihydroxy bile salt-induced K/sup +/ secretion by the mammalian colon were evaluated by studying the effects of taurochenodeoxycholate (TCDC) on /sup 86/Rb/sup +/ transport across the isolated, short-circuited rabbit distal colon. Simultaneous measurements of /sup 86/Rb/sup +/ and /sup 42/K/sup +/ unidirectional fluxes were highly correlated, indicating that Rb/sup +/ is a suitable tracer for K/sup +/ transport across the colon. Furthermore, mucosal Ba/sup 2 +/ (4 mM) or serosal ouabain (0.1 mM) decreased serosal to mucosal rubidium flux (J/sub s ..-->.. m//sup Rb/) without affecting J/sub m ..-->.. s//sup Rb/. Dibutyryl cyclic adenosine monophosphate (dBcAMP, 0.5 mM serosal) specifically increased J/sub s ..-->.. m//sup Rb of controls through a barium- (4 mM, mucosal) sensitive pathway without affecting J/sub s ..-->.. m//Rb/. Mucosal addition of 2 mM TCDC increased tissue conductance (G/sub T/), reduced short-circuit (I/sub sc/) slightly, and reversed J/sub net//sup Rb/ principally by increasing J/sub s ..-->.. m//sup Rb/. The TCDC-induced increases in J/sub s ..-->.. m//sup Rb/ were reduced by 0.1 mM serosal ouabain or 4 mM mucosal Ba/sup 2 +/. Pretreatment with the putative calcium-calmodulin antagonist trifluoperazine blocked dBcAMP- and TCDC-induced increases in J/sub s ..-->.. m//sup Rb/ but did not prevent changes in G/sub T/ or I/sub sc/ produced by either secretagogue. It is concluded that TCDC stimulates Rb/sup +/ or K/sup +/ secretion by primarily increasing the efflux of these ions across Ba/sup 2 +/-sensitive K/sup +/ channels in the apical membrane and that this increase in permeability may be mediated intracellularly by the calcium-calmodulin complex.

• Research Organization: Louisiana State Univ., Baton Rouge
• OSTI ID: 5879277
• Journal Information: Am. J. Physiol.; (United States), Journal Name: Am. J. Physiol.; (United States) Vol. 252:4; ISSN AJPHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALKALI METAL COMPOUNDS
ALKALI METAL ISOTOPES
AMP
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMISTRY
BODY
CARBOHYDRATES
CARBOXYLIC ACID SALTS
CARDIAC GLYCOSIDES
CARDIOTONICS
CARDIOVASCULAR AGENTS
CATIONS
CHARGED PARTICLES
CHEMISTRY
CHLORIDES
CHLORINE COMPOUNDS
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
DRUGS
GASTROINTESTINAL TRACT
GLYCOSIDES
HALIDES
HALOGEN COMPOUNDS
HOURS LIVING RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
INTESTINES
IONS
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LARGE INTESTINE
MAMMALS
MEMBRANE TRANSPORT
MEMBRANES
MINUTES LIVING RADIOISOTOPES
MUCOUS MEMBRANES
NUCLEI
NUCLEOTIDES
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANS
OUABAIN
POTASSIUM 42
POTASSIUM CHLORIDES
POTASSIUM COMPOUNDS
POTASSIUM ISOTOPES
RABBITS
RADIOISOTOPES
RUBIDIUM 86
RUBIDIUM CHLORIDES
RUBIDIUM COMPOUNDS
RUBIDIUM ISOTOPES
SECRETION
STROPHANTHINS
VERTEBRATES