Calcium channels in thrombin-activated human platelet membrane

A. Zschauer, C. Van Breemen, F. R. Buhler, M. T. Nelson

    Research output: Contribution to journalArticlepeer-review


    Platelet-activating factor, 5-hydroxytryptamine, thromboxane A2, adenosine diphosphate and thrombin are known to activate platelets by stimulating calcium entry, but the nature of the entry pathways is unknown. We present the identification of single divalent cation channels from thrombin-activated human platelets. Membrane vesicles from unstimulated and thrombin-stimulated human platelets were incorporated in planar bilayers and unitary currents through single channels were measured. Divalent cation selective channels could only be demonstrated in thrombin-stimulated preparations. These channels share a number of properties in common with voltage-dependent calcium channels - a high degree of selectivity for divalent cations, a single channel conductance of about 10 pS (in 150 mM Ba2+) and sensitivity to blockade by inorganic calcium channel blockers such as Ni2+. In other respects, these channels are different as they are not voltage-dependent and are not blocked by 1,4-dihydropyridine calcium channel antagonists.
    Original languageEnglish
    Pages (from-to)703-705
    Number of pages2
    Issue number6184
    Publication statusPublished - 1988


    • blood: Barium
    • drug effects: Blood Platelets
    • blood: Calcium
    • Calcium Channel Blockers
    • Cations, Divalent
    • drug effects: Cell Membrane
    • Electric Conductivity
    • Humans
    • drug effects: Ion Channels
    • metabolism: Lipid Bilayers
    • Membrane Potentials
    • pharmacology: Nickel
    • analogs & derivatives: Nifedipine
    • Nisoldipine
    • blood: Sodium
    • pharmacology: Thrombin


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