PMID: 8963947Jan 1, 1996Paper

Recirculation fraction of the activator Ca2+: index of the extent of Ca2+ loading of rat myocardium during ischemia-reperfusion

Canadian Journal of Physiology and Pharmacology
J S Juggi

Abstract

The recirculation fraction (RF) of the activator Ca2+ of the cardiac muscle is an index of the fraction of the internally released Ca2+ sequestered by the sarcoplasmic reticulum during each contraction-relaxation cycle. Estimates of the RF were obtained by the slope method during the decline of the post-rest potentiation in the isolated aorta-perfused rat heart. Normalized contractile force P(max) of the second post-interval beat, B2, was plotted as a function of the first post-interval beat, B1, and fitted by a linear regression line. The correlation coefficient (r2) and the slope of the line were computed. Under the control experimental perfusion with oxygenated (95% O2-5% CO2) Krebs-Henseleit buffer ([Ca2+]0 1.25 mM, 34 degrees C, ph 7.40), the slope of the line, representing the RF of the rat left ventricle, was 0.73 +/- 0.01 (mean +/- SE) (r2 0.95 +/- 0.01). Increasing the stimulation frequency from 1 to 3.3 Hz produced a negative inotropic effect and significantly reduced the RF, to 0.17 +/- 0.02. Positive inotropic interventions significantly increased the RF, to 0.95 +/- 0.05 with [Ca2+]0 4 mM and to 0.92 +/- 0.04 with a 30% reduction in [Na+]0, whereas inhibition of Ca2+ release from the sarcoplasmic reticulum by ryano...Continue Reading

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Citations

Sep 22, 2010·Pflügers Archiv : European journal of physiology·Marie-Louise WardMark B Cannell
Jun 30, 2011·Clinical and Experimental Pharmacology & Physiology·Marie-Louise WardMark B Cannell
May 14, 2016·Circulation·Steven HsuRyan J Tedford

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