Mitochondrial free calcium transients during excitation‐contraction coupling in rabbit cardiac myocytes

FEBS Letters

Lemasters, John J¹  Harper, Ian S¹  Ohata, Hisayuki¹  Chacon, Enrique¹  Herman, Brian¹  Trollinger, Donna R¹ 

[1] Laboratories for Cell Biology, Department of Cell Biology & Anatomy and Curriculum in Toxicology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7090, USA

关键词: Calcium;    Confocal microscopy;    Excitation-contraction coupling;    Mitochondria;    Myocyte;   

DOI  :  10.1016/0014-5793(96)00138-X

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Mitochondrial free Ca²⁺ may regulate mitochondrial ATP production during cardiac exercise. Here, using laser scanning confocal microscopy of adult rabbit cardiac myocytes co-loaded with Fluo-3 to measure free Ca²⁺ and tetramethylrhodamine methylester to identify mitochondria, we measured cytosolic and mitochondrial Ca²⁺ transients during the contractile cycle. In resting cells, cytosolic and mitochondrial Fluo-3 signals were similar. During electrical pacing, transients of Fluo-3 fluorescence occurred in both the cytosolic and mitochondrial compartments. Both the mitochondrial and the cytosolic transients were potentiated by isoproterenol. These experiments show directly that mitochondrial free Ca²⁺ rises and falls during excitation-contraction coupling in cardiac myocytes and that changes of mitochondrial Ca²⁺ are kinetically component to regulate mitochondrial metabolism on a beat-to-beat basis.

【 授权许可】

Unknown