Length dependence of Ca(2+)-tension relationship in aequorin-injected ferret papillary muscles.

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  • Author(s): Komukai K;Komukai K; Kurihara S
  • Source:
    The American journal of physiology [Am J Physiol] 1997 Sep; Vol. 273 (3 Pt 2), pp. H1068-74.
  • Publication Type:
    Journal Article; Research Support, Non-U.S. Gov't
  • Language:
    English
  • Additional Information
    • Source:
      Publisher: American Physiological Society Country of Publication: United States NLM ID: 0370511 Publication Model: Print Cited Medium: Print ISSN: 0002-9513 (Print) Linking ISSN: 00029513 NLM ISO Abbreviation: Am J Physiol Subsets: MEDLINE
    • Publication Information:
      Publication: Bethesda, MD : American Physiological Society
      Original Publication: Washington [etc.] American Physiological Society.
    • Subject Terms:
      Calcium/*metabolism ; Myocardial Contraction/*physiology ; Papillary Muscles/*physiology; Aequorin ; Animals ; Electric Stimulation ; Ferrets ; Isoproterenol/pharmacology ; Myocardial Contraction/drug effects ; Papillary Muscles/drug effects ; Phosphorylation ; Ryanodine/pharmacology ; Troponin C/metabolism ; Troponin I/metabolism
    • Abstract:
      The possible contractile proteins, which are related to the length-dependent change in the relationship between intracellular Ca2+ concentration ([Ca2+]i) and tension, were investigated using aequorin-injected ferret papillary muscles. Tetanic contraction was produced by applying repetitive stimulation to the ryanodine-treated preparations, and the relationships between [Ca2+]i and tension were measured. When the muscle length was decreased from maximal length (Lmax), at which maximal tension is produced, to 95 and 90% Lmax, the maximal tension was significantly decreased. [Ca2+]i required for producing 50% of the maximal tension was significantly increased from 1.05 +/- 0.04 microM (Lmax) to 1.17 +/- 0.04 microM (95% Lmax) and to 1.22 +/- 0.04 microM (90% Lmax). Isoproterenol (Iso) accentuated the length-dependent change in the [Ca2+]i-tension relationship. The decrease in the Ca2+ sensitivity induced by Iso was larger at shorter muscle lengths compared with that at Lmax. It is, therefore, suggested that adenosine 3',5'-cyclic monophosphate-dependent phosphorylation of troponin I and/or C protein alters the length dependence of the [Ca2+]i-tension relationship and that troponin I and/or C protein might be involved in the length-tension-dependent change in the affinity of the contractile elements for Ca2+.
    • Accession Number:
      0 (Troponin C)
      0 (Troponin I)
      15662-33-6 (Ryanodine)
      50934-79-7 (Aequorin)
      L628TT009W (Isoproterenol)
      SY7Q814VUP (Calcium)
    • Publication Date:
      Date Created: 19971010 Date Completed: 19971023 Latest Revision: 20171213
    • Publication Date:
      20250114
    • Accession Number:
      10.1152/ajpheart.1997.273.3.H1068
    • Accession Number:
      9321790