Calcium and ATP regulate the activity of a non-selective cation channel in a rat insulinoma cell line

N. C. Sturgess, C. N. Hales, M. L. J. Ashford

    Research output: Contribution to journalArticle

    69 Citations (Scopus)

    Abstract

    A calcium-activated non-selective cation channel was observed in isolated plasma membrane patches from an insulin-secreting cell line (CRI-Gl). The conductance of the channel was approximately 25 pS with identical (140 mM KCl) solutions on either side of the membrane. However, some rectification was observed (smaller outward current) when sodium ions were present extracellularly. The channel was inactive on exposure to an intracellular calcium concentration of 10(-6) M and required high (greater than 10(-4) M) concentrations for a significant degree of activation. The open-state probability of the channel was voltage dependent, increasing with membrane depolarization. Analysis of single channel kinetics indicated that there were at least two open and two closed states. Application of ATP to the cytoplasmic membrane surface reduced the open state probability in a dose-dependent manner. The channel activity was blocked by quinine and 4-AP but was insensitive to TEA, TTX and amiloride. It is not clear what role this channel might play in the complex electrical activity of ß-cells.

    Original languageEnglish
    Pages (from-to)607-615
    Number of pages9
    JournalPflugers Archiv-European Journal of Physiology
    Volume409
    Issue number6
    Publication statusPublished - Aug 1987

    Fingerprint

    Insulinoma
    Cations
    Rats
    Adenosine Triphosphate
    Cells
    Cell Membrane
    Calcium
    Membranes
    Cell Line
    Quinine
    Amiloride
    Insulin-Secreting Cells
    Sodium
    Depolarization
    Cell membranes
    Ions
    Chemical activation
    Insulin
    Kinetics
    Electric potential

    Keywords

    • Animals
    • Calcium
    • Quinine
    • Insulinoma
    • Ion Channels
    • Adenoma, Islet Cell
    • Aminopyridines
    • Rats
    • Cations
    • Kinetics
    • Membrane Potentials
    • 4-Aminopyridine
    • Adenosine Triphosphate
    • Cell Line

    Cite this

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    title = "Calcium and ATP regulate the activity of a non-selective cation channel in a rat insulinoma cell line",
    abstract = "A calcium-activated non-selective cation channel was observed in isolated plasma membrane patches from an insulin-secreting cell line (CRI-Gl). The conductance of the channel was approximately 25 pS with identical (140 mM KCl) solutions on either side of the membrane. However, some rectification was observed (smaller outward current) when sodium ions were present extracellularly. The channel was inactive on exposure to an intracellular calcium concentration of 10(-6) M and required high (greater than 10(-4) M) concentrations for a significant degree of activation. The open-state probability of the channel was voltage dependent, increasing with membrane depolarization. Analysis of single channel kinetics indicated that there were at least two open and two closed states. Application of ATP to the cytoplasmic membrane surface reduced the open state probability in a dose-dependent manner. The channel activity was blocked by quinine and 4-AP but was insensitive to TEA, TTX and amiloride. It is not clear what role this channel might play in the complex electrical activity of {\ss}-cells.",
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    author = "Sturgess, {N. C.} and Hales, {C. N.} and Ashford, {M. L. J.}",
    year = "1987",
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    volume = "409",
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    Calcium and ATP regulate the activity of a non-selective cation channel in a rat insulinoma cell line. / Sturgess, N. C.; Hales, C. N.; Ashford, M. L. J.

    In: Pflugers Archiv-European Journal of Physiology, Vol. 409, No. 6, 08.1987, p. 607-615.

    Research output: Contribution to journalArticle

    TY - JOUR

    T1 - Calcium and ATP regulate the activity of a non-selective cation channel in a rat insulinoma cell line

    AU - Sturgess, N. C.

    AU - Hales, C. N.

    AU - Ashford, M. L. J.

    PY - 1987/8

    Y1 - 1987/8

    N2 - A calcium-activated non-selective cation channel was observed in isolated plasma membrane patches from an insulin-secreting cell line (CRI-Gl). The conductance of the channel was approximately 25 pS with identical (140 mM KCl) solutions on either side of the membrane. However, some rectification was observed (smaller outward current) when sodium ions were present extracellularly. The channel was inactive on exposure to an intracellular calcium concentration of 10(-6) M and required high (greater than 10(-4) M) concentrations for a significant degree of activation. The open-state probability of the channel was voltage dependent, increasing with membrane depolarization. Analysis of single channel kinetics indicated that there were at least two open and two closed states. Application of ATP to the cytoplasmic membrane surface reduced the open state probability in a dose-dependent manner. The channel activity was blocked by quinine and 4-AP but was insensitive to TEA, TTX and amiloride. It is not clear what role this channel might play in the complex electrical activity of ß-cells.

    AB - A calcium-activated non-selective cation channel was observed in isolated plasma membrane patches from an insulin-secreting cell line (CRI-Gl). The conductance of the channel was approximately 25 pS with identical (140 mM KCl) solutions on either side of the membrane. However, some rectification was observed (smaller outward current) when sodium ions were present extracellularly. The channel was inactive on exposure to an intracellular calcium concentration of 10(-6) M and required high (greater than 10(-4) M) concentrations for a significant degree of activation. The open-state probability of the channel was voltage dependent, increasing with membrane depolarization. Analysis of single channel kinetics indicated that there were at least two open and two closed states. Application of ATP to the cytoplasmic membrane surface reduced the open state probability in a dose-dependent manner. The channel activity was blocked by quinine and 4-AP but was insensitive to TEA, TTX and amiloride. It is not clear what role this channel might play in the complex electrical activity of ß-cells.

    KW - Animals

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    KW - Quinine

    KW - Insulinoma

    KW - Ion Channels

    KW - Adenoma, Islet Cell

    KW - Aminopyridines

    KW - Rats

    KW - Cations

    KW - Kinetics

    KW - Membrane Potentials

    KW - 4-Aminopyridine

    KW - Adenosine Triphosphate

    KW - Cell Line

    M3 - Article

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    VL - 409

    SP - 607

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    JO - Pflugers Archiv-European Journal of Physiology

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    SN - 0031-6768

    IS - 6

    ER -