Basolateral K sup + channels in airway epithelia. I. Regulation by Ca sup 2+ and block by charybdotoxin

Journal Article · Fri Jun 01 00:00:00 EDT 1990 · American Journal of Physiology; (USA)

OSTI ID:6874817

McCann, J D; Matsuda, J; Garcia, M; Kaczorowski, G; Welsh, M J ^[1]

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1. Univ. of Iowa, Iowa City (USA)

In airway epithelia, adenosine 3',5'-cyclic monophosphate (cAMP) stimulates Cl- secretion by activating apical membrane Cl- channels and basolateral membrane K+ channels. Cl- channels are regulated by cAMP-dependent phosphorylation, whereas K+ channels are regulated by the cytosolic Ca2+ concentration, (Ca2+)c. Our recent observation that cAMP increases (Ca2+)c suggested that cAMP might indirectly regulate K+ channels by increasing (Ca2+)c. To study regulation of K+ channels we measured 86Rb efflux, single K+ channels in membrane patches, and (Ca2+)c with the fluorescent indicator fura-2. Isoproterenol and Ca2+ ionophore, A23187, transiently increased (Ca2+)c and transiently stimulated 86Rb efflux. Stimulation of 86Rb efflux resulted from release of intracellular Ca2+ stores. 86Rb efflux was blocked by Ba2+ or charybdotoxin, but not by tetraethylammonium. Charybdotoxin prevented all of the 86Rb efflux that was stimulated by A23187 or by forskolin. Charybdotoxin also blocked the low-conductance inwardly rectifying K+ channel (KCLIC) in membrane patches. These results indicate that the KCLIC channel is responsible for the Ca2(+)-dependent increase in K+ permeability in airway epithelial cells. They also indicate that cAMP-induced release of intracellular Ca2+ is sufficient to activate K+ channels.

• OSTI ID: 6874817
• Journal Information: American Journal of Physiology; (USA), Vol. 258; ISSN 0002-9513
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
CALCIUM COMPOUNDS
MEMBRANE TRANSPORT
CELL MEMBRANES
PERMEABILITY
POTASSIUM COMPOUNDS
AMP
BARIUM
CELL CULTURES
CHLORIDES
DOGS
DYES
ELECTROPHYSIOLOGY
EPITHELIUM
FLUORESCENCE
HOMEOSTASIS
MUSCLES
RUBIDIUM 86
TOXINS
TRACER TECHNIQUES
TRACHEA
ALKALI METAL COMPOUNDS
ALKALI METAL ISOTOPES
ALKALINE EARTH METAL COMPOUNDS
ALKALINE EARTH METALS
ANIMAL TISSUES
ANIMALS
ANTIGENS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CELL CONSTITUENTS
CHLORINE COMPOUNDS
DAYS LIVING RADIOISOTOPES
ELEMENTS
HALIDES
HALOGEN COMPOUNDS
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LUMINESCENCE
MAMMALS
MATERIALS
MEMBRANES
METALS
MINUTES LIVING RADIOISOTOPES
NUCLEI
NUCLEOTIDES
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
PHYSIOLOGY
RADIOISOTOPES
RESPIRATORY SYSTEM
RUBIDIUM ISOTOPES
TISSUES
TOXIC MATERIALS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques