An ultrastructural study of calcium induced degenerative changes in dissociated heart cells

M. A. Russo, A. Cittadini, A. M. Dani, G. Inesi, T. Terranova

Research output: Contribution to journalArticle

Abstract

Dissociated myocytes were prepared by enzymatic perfusion of adult rabbit hearts, and fixed following exposure to various concentrations of Ca2+. Only slight ultrastructural changes were noted in myocytes which were maintained in relaxation [(Ca2+) <0.1 μm] or in cyclic contractile activity [(Ca2+) ≅ 0.4 μm]. In these cells, slight swelling permitted clear demonstration of interesting ultrastructural details such as tight connections between Z bands and sarcolemma, attachment of filaments to these structures, and relationships of sarcoplasmic reticulum and T tubules. When the Ca2+ concentration was raised above 1.0 μm, sarcomeres exhibited extreme and irreversible shortening, followed by myofilament disorganization, disappearance of Z lines, aggregation of most thick and some thin filaments forming a central mass, and outward displacement of organelles. Under these conditions numerous filaments were attached randomly to the sarcolemma and to intracellular membranes, demonstrating their inherent capacity to bind to membranous structures. The ultrastructural alterations observed in our experiments are similar to those described for the "calcium paradox", which is likely to be a common pathogenic mechanism of myocardial cell damage.

Original languageEnglish
Pages (from-to)265-279
Number of pages15
JournalJournal of Molecular and Cellular Cardiology
Volume13
Issue number3
DOIs
Publication statusPublished - 1981

Keywords

  • Calcium
  • Calcium buffering system
  • Dissociated myocytes
  • Intracellular calcium
  • Myocyte damage
  • Myocyte ultrastructure
  • Myofilament organization

ASJC Scopus subject areas

  • Molecular Biology
  • Cardiology and Cardiovascular Medicine

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