Regulation of conductive Cl sup minus transport in human fibroblasts

Journal Article · Sat Oct 01 00:00:00 EDT 1988 · American Journal of Physiology; (USA)

OSTI ID:6037301

Lin, Peiyuan; Ahluwalia, M; Gruenstein, E ^[1]

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1. Univ. of Cincinnati College of Medicine, OH (USA)

Under normal growth conditions, {approximately}20% of the efflux of {sup 36}Cl{sup {minus}} from human fibroblasts occurs via an electrically conductive pathway or Cl{sup {minus}} channel. This basal Cl{sup {minus}} conductance is insensitive to the Cl{sup {minus}}-anion exchange inhibitor 4,4{prime}-diisothiocyanostilbene-2,2{prime}-disulfonic acid (DIDS) and to the Cl{sup {minus}}-cation cotransport inhibitor bumetanide. Exposure of the cells to dibutyryl adenosine 3{prime},5{prime}-cyclic monosphosphate (cAMP) for 15 min increases the electrically conductive component of {sup 36}Cl{sup {minus}} efflux by {approximately}20%. Unlike the basal Cl{sup {minus}} conductance, the cAMP-activated channel is DIDS sensitive, indicating that cAMP activates a different Cl{sup {minus}} pathway from the one responsible for the basal Cl{sup {minus}} conductance. Elevation of intracellular Ca{sup 2+} by addition of the ionophore A23187 also stimulates {sup 36}Cl{sup {minus}} efflux via a DIDS inhibitable, electrically conductive Cl{sup {minus}} pathway. That the cAMP- and Ca{sup 2+}-stimulated pathways are different is suggested by the observation that simultaneous exposure of cells to optimal levels of dibutyryl cAMP and A23187 results in an increased Cl{sup {minus}} efflux equal to the sum of the two factors acting independently. Prostaglandin E{sub 1}, a known activator of adenylate cyclase, also elevates the levels of intracellular free Ca{sup 2+} in these cells and concomitantly activates both the cAMP- and the Ca{sup 2+}-stimulated Cl{sup {minus}} channels. Although regulated, Cl{sup {minus}} channels are known to function in the modulation of nerve and muscle excitability, their role in fibroblast function is not clear.

• OSTI ID: 6037301
• Journal Information: American Journal of Physiology; (USA), Journal Name: American Journal of Physiology; (USA) Vol. 255:4; ISSN 0002-9513; ISSN AJPHA
• Country of Publication: United States
• Language: English

Related Subjects

551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALKALINE EARTH METAL COMPOUNDS
AMP
ANIMAL CELLS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL EFFECTS
BIOLOGICAL PATHWAYS
CALCIUM CHLORIDES
CALCIUM COMPOUNDS
CALCIUM HALIDES
CHLORIDES
CHLORINE 36
CHLORINE COMPOUNDS
CHLORINE ISOTOPES
CONNECTIVE TISSUE CELLS
ELECTRON CAPTURE RADIOISOTOPES
ESTERS
FIBROBLASTS
HALIDES
HALOGEN COMPOUNDS
ISOTOPES
KINETICS
LIGHT NUCLEI
MAMMALS
MAN
MEMBRANE TRANSPORT
NUCLEI
NUCLEOTIDES
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PRIMATES
PROSTAGLANDINS
RADIOISOTOPES
REACTION KINETICS
SOMATIC CELLS
SULFONIC ACID ESTERS
UPTAKE
VERTEBRATES
YEARS LIVING RADIOISOTOPES