Thorac Cardiovasc Surg 2004; 52(3): 127-134
DOI: 10.1055/s-2004-817978
Original Cardiovascular

© Georg Thieme Verlag KG Stuttgart · New York

Protein Kinase C and Myocardial Calcium Handling during Ischemia and Reperfusion: Lessons Learned using Rhod-2 Spectrofluorometry

C. Stamm1 , P. J. del Nido2
  • 1Klinik und Poliklinik für Herzchirurgie, Universität Rostock, Rostock, Germany
  • 2Children's Hospital Boston, Harvard Medical School, Boston, USA
Further Information

Publication History

Received January 21, 2004

Publication Date:
11 June 2004 (online)

Abstract

Objective: We sought to assess myocardial Ca2+ handling and excitation-contraction coupling in surgically relevant models of ischemia-reperfusion injury and to clarify the importance of protein kinase C (PKC) for cardioprotection. Methods: Experimentally, surgical ischemia and reperfusion can only be mimicked in intact perfused heart models. We introduced the long-wavelength fluorescent Ca2+ indicator Rhod-2 for real-time recording of cytosolic Ca2+ transients in Langendorff-perfused rabbit, rat, and mouse hearts, and utilized it to study the impact of PKC on myocardial Ca2+ handling during ischemia and reperfusion. Results: We first established that the dissociation constant for Rhod-2 and Ca2+ must be adjusted to account for changes in pH and temperature during ischemia and reperfusion. Based on this method, we determined the time-course and extent of cytosolic Ca2+ accumulation during myocardial ischemia, which is associated with translocation of the PKC isoforms α and ε between the cytosolic and particulate compartments in cardiomyocytes. The PKC translocation is mediated by activation of phosphatidyl-inositol-specific phospholipase C (PI-PLC), and represents a cardioprotective mechanism. Finally, we studied the mechanism of action of PKC and found that it both limits the accumulation of cytosolic Ca2+ during reperfusion and attenuates contractile protein Ca2+ sensitivity via phosphorylation of troponin I. Conclusions: Rhod-2 spectrofluorometry is a valuable tool for assessment of cytosolic Ca2+ in surgically relevant experimental models and can aid the development of more effective methods for myocardial protection.

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PD Dr. Christof Stamm

Universität Rostock
Klinik und Poliklinik für Herzchirurgie

Schillingallee 35

18057 Rostock

Germany

Phone: + 493814946101

Fax: + 49 38 14 94 61 02

Email: christof.stamm@med.uni-rostock.de

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