Cl/sup -/ transport pathways regulated by Ca/sup + +/, cAMP, and pH in human fibroblasts

Conference · Fri May 01 04:00:00 EDT 1987 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:5856693

Lin, P; Gruenstein, E

Under basal conditions Cl/sup -/ efflux from human fibroblasts occurs with a rate constant of permeability of 0.08 min/sup -1/. 50% of the basal efflux is due to Cl/sup -//anion exchange and is DIDS inhibitable, 25% is due to Na/sup +//K/sup +//Cl/sup -/ cotransport and is furosemide inhibitable, and 20% is due to an electrically conductive pathway. Increasing intracellular Ca/sup + +/ with A23187 stimulates Cl/sup -/ efflux by 30%. This increase appears to occur entirely via an electrically conducting pathway, but unlike basal Cl/sup -/ conductance, it is DIDS sensitive. Exposure of the cells to dibutyryl cAMP stimulates Cl/sup -/ efflux by 15%. They do not yet know whether the cAMP stimulated pathway is electrically conductive, but the stimulation is additive with that caused by elevated Ca/sup + +/ suggesting that different pathways are activated. Elevation of intracellular pH by any of several standard methods increases Cl/sup -/ efflux by as much as 700%. The pH effect appears to be mediated by a Cl/sup -//anion exchange pathway since it is DIDS sensitive and electroneutral. Previous work from this laboratory describing a transient rapid efflux of Cl/sup -/ followed by a slower efflux phase can now be explained as the result of a transient alkalinization of cells rather than as 2 subcellular Cl/sup -/ compartments. This alkalinization occurs when cells are transferred from a 5% CO/sub 2/ atmosphere during /sup 36/Cl/sup -/ load to ambient CO/sub 2/ for efflux.

• Research Organization: Univ. of Cincinnati, OH
• OSTI ID: 5856693
• Report Number(s): CONF-870644-
• Conference Information: Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 46:6
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
AMP
ANIMAL CELLS
ANIONS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOELECTRICITY
CALCIUM COMPOUNDS
CATIONS
CHARGED PARTICLES
CHLORIDES
CHLORINE 36
CHLORINE COMPOUNDS
CHLORINE ISOTOPES
CONNECTIVE TISSUE CELLS
ELECTRICITY
ELECTRON CAPTURE RADIOISOTOPES
FIBROBLASTS
HALIDES
HALOGEN COMPOUNDS
INHIBITION
IONS
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LABELLED COMPOUNDS
LIGHT NUCLEI
MEMBRANE TRANSPORT
NUCLEI
NUCLEOTIDES
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
PERMEABILITY
PH VALUE
POTASSIUM COMPOUNDS
RADIOISOTOPES
REACTION KINETICS
RESPONSE MODIFYING FACTORS
SODIUM COMPOUNDS
SOMATIC CELLS
TRACER TECHNIQUES
YEARS LIVING RADIOISOTOPES