Effects of pH on spontaneous tension oscillation in skinned bovine cardiac muscle

Norio Fukuda, Shin'ichi Ishiwata

    研究成果: Article

    18 引用 (Scopus)

    抄録

    Skinned cardiac muscle preparations exhibit spontaneous tension oscillations (spontaneous oscillatory contractions; SPOCs) in the absence of Ca2+, and in the presence of MgATP, MgADP and inorganic phosphate (Pi; ADP- SPOC). Similar oscillations occur in the presence of sub-micromolar concentrations of Ca2+ under normal activating conditions without MgADP and Pi (Ca-SPOC). In the study presented here, we investigated the effects of pH on both types of SPOC in skinned bovine cardiac ventricular muscle. First, a decrease in pH increased the MgADP concentration required to induce the half- maximal isometric tension that is obtained in the absence of Ca2+ and in the presence of MgATP (ADP-contraction). The inhibitory effect of Pi on ADP- contractions was not affected by pH. Second, ADP-SPOCs occurred upon the addition of Pi to the solution that resulted in ADP-contraction, and the relative amplitude and the period of the tension oscillation in the presence of 2 mM MgATP, 10 mM MgADP and 10 mM Pi were unchanged under all pH conditions examined (6.6, 7.0, 7.4). On the contrary, the relative amplitude and the period of the Ca-SPOCs were markedly diminished at pH 6.6. Finally, we constructed state diagrams showing the effects of pH on SPOC conditions. The state diagram shows that SPOCs occur less frequently under acidic conditions than at neutral pH. We suggest that the intermediate state of crossbridges that is required for SPOCs is more difficult to attain at a low pH.

    元の言語English
    ページ(範囲)125-132
    ページ数8
    ジャーナルPflugers Archiv European Journal of Physiology
    438
    発行部数2
    DOI
    出版物ステータスPublished - 1999

    Fingerprint

    Adenosine Diphosphate
    Muscle
    Myocardium
    Adenosine Triphosphate
    Phosphates

    ASJC Scopus subject areas

    • Physiology

    これを引用

    Effects of pH on spontaneous tension oscillation in skinned bovine cardiac muscle. / Fukuda, Norio; Ishiwata, Shin'ichi.

    :: Pflugers Archiv European Journal of Physiology, 巻 438, 番号 2, 1999, p. 125-132.

    研究成果: Article

    Fukuda, Norio ; Ishiwata, Shin'ichi. / Effects of pH on spontaneous tension oscillation in skinned bovine cardiac muscle. :: Pflugers Archiv European Journal of Physiology. 1999 ; 巻 438, 番号 2. pp. 125-132.
    @article{f660bcbe96784b62817d1035e5030971,
    title = "Effects of pH on spontaneous tension oscillation in skinned bovine cardiac muscle",
    abstract = "Skinned cardiac muscle preparations exhibit spontaneous tension oscillations (spontaneous oscillatory contractions; SPOCs) in the absence of Ca2+, and in the presence of MgATP, MgADP and inorganic phosphate (Pi; ADP- SPOC). Similar oscillations occur in the presence of sub-micromolar concentrations of Ca2+ under normal activating conditions without MgADP and Pi (Ca-SPOC). In the study presented here, we investigated the effects of pH on both types of SPOC in skinned bovine cardiac ventricular muscle. First, a decrease in pH increased the MgADP concentration required to induce the half- maximal isometric tension that is obtained in the absence of Ca2+ and in the presence of MgATP (ADP-contraction). The inhibitory effect of Pi on ADP- contractions was not affected by pH. Second, ADP-SPOCs occurred upon the addition of Pi to the solution that resulted in ADP-contraction, and the relative amplitude and the period of the tension oscillation in the presence of 2 mM MgATP, 10 mM MgADP and 10 mM Pi were unchanged under all pH conditions examined (6.6, 7.0, 7.4). On the contrary, the relative amplitude and the period of the Ca-SPOCs were markedly diminished at pH 6.6. Finally, we constructed state diagrams showing the effects of pH on SPOC conditions. The state diagram shows that SPOCs occur less frequently under acidic conditions than at neutral pH. We suggest that the intermediate state of crossbridges that is required for SPOCs is more difficult to attain at a low pH.",
    keywords = "Cardiac muscle, Oscillation, SPOC, Spontaneous tension oscillation, State diagram of muscle",
    author = "Norio Fukuda and Shin'ichi Ishiwata",
    year = "1999",
    doi = "10.1007/s004240050889",
    language = "English",
    volume = "438",
    pages = "125--132",
    journal = "Pflugers Archiv European Journal of Physiology",
    issn = "0031-6768",
    publisher = "Springer Verlag",
    number = "2",

    }

    TY - JOUR

    T1 - Effects of pH on spontaneous tension oscillation in skinned bovine cardiac muscle

    AU - Fukuda, Norio

    AU - Ishiwata, Shin'ichi

    PY - 1999

    Y1 - 1999

    N2 - Skinned cardiac muscle preparations exhibit spontaneous tension oscillations (spontaneous oscillatory contractions; SPOCs) in the absence of Ca2+, and in the presence of MgATP, MgADP and inorganic phosphate (Pi; ADP- SPOC). Similar oscillations occur in the presence of sub-micromolar concentrations of Ca2+ under normal activating conditions without MgADP and Pi (Ca-SPOC). In the study presented here, we investigated the effects of pH on both types of SPOC in skinned bovine cardiac ventricular muscle. First, a decrease in pH increased the MgADP concentration required to induce the half- maximal isometric tension that is obtained in the absence of Ca2+ and in the presence of MgATP (ADP-contraction). The inhibitory effect of Pi on ADP- contractions was not affected by pH. Second, ADP-SPOCs occurred upon the addition of Pi to the solution that resulted in ADP-contraction, and the relative amplitude and the period of the tension oscillation in the presence of 2 mM MgATP, 10 mM MgADP and 10 mM Pi were unchanged under all pH conditions examined (6.6, 7.0, 7.4). On the contrary, the relative amplitude and the period of the Ca-SPOCs were markedly diminished at pH 6.6. Finally, we constructed state diagrams showing the effects of pH on SPOC conditions. The state diagram shows that SPOCs occur less frequently under acidic conditions than at neutral pH. We suggest that the intermediate state of crossbridges that is required for SPOCs is more difficult to attain at a low pH.

    AB - Skinned cardiac muscle preparations exhibit spontaneous tension oscillations (spontaneous oscillatory contractions; SPOCs) in the absence of Ca2+, and in the presence of MgATP, MgADP and inorganic phosphate (Pi; ADP- SPOC). Similar oscillations occur in the presence of sub-micromolar concentrations of Ca2+ under normal activating conditions without MgADP and Pi (Ca-SPOC). In the study presented here, we investigated the effects of pH on both types of SPOC in skinned bovine cardiac ventricular muscle. First, a decrease in pH increased the MgADP concentration required to induce the half- maximal isometric tension that is obtained in the absence of Ca2+ and in the presence of MgATP (ADP-contraction). The inhibitory effect of Pi on ADP- contractions was not affected by pH. Second, ADP-SPOCs occurred upon the addition of Pi to the solution that resulted in ADP-contraction, and the relative amplitude and the period of the tension oscillation in the presence of 2 mM MgATP, 10 mM MgADP and 10 mM Pi were unchanged under all pH conditions examined (6.6, 7.0, 7.4). On the contrary, the relative amplitude and the period of the Ca-SPOCs were markedly diminished at pH 6.6. Finally, we constructed state diagrams showing the effects of pH on SPOC conditions. The state diagram shows that SPOCs occur less frequently under acidic conditions than at neutral pH. We suggest that the intermediate state of crossbridges that is required for SPOCs is more difficult to attain at a low pH.

    KW - Cardiac muscle

    KW - Oscillation

    KW - SPOC

    KW - Spontaneous tension oscillation

    KW - State diagram of muscle

    UR - http://www.scopus.com/inward/record.url?scp=0032968465&partnerID=8YFLogxK

    UR - http://www.scopus.com/inward/citedby.url?scp=0032968465&partnerID=8YFLogxK

    U2 - 10.1007/s004240050889

    DO - 10.1007/s004240050889

    M3 - Article

    C2 - 10370097

    AN - SCOPUS:0032968465

    VL - 438

    SP - 125

    EP - 132

    JO - Pflugers Archiv European Journal of Physiology

    JF - Pflugers Archiv European Journal of Physiology

    SN - 0031-6768

    IS - 2

    ER -