Cardiac myocyte volume, Ca2+ fluxes, and sarcoplasmic reticulum loading in pressure-overload hypertrophy

The American Journal of Physiology
L M DelbridgeD M Bers

Abstract

Alterations in cellular Ca2+ transport and excitation-contraction coupling may contribute to dysfunction in cardiac hypertrophy. Left ventricular myocytes were isolated from rat hearts after 15-18 wk of suprarenal abdominal aortic banding to evaluate the hypothesis that hypertrophy alters the relationship between Ca2+ current (ICa) and sarcoplasmic reticulum (SR) Ca2+ load during steady-state voltage-clamp depolarization. Mean arterial pressure (MAP) and heart weight-to-body weight ratio of banded (B) animals were significantly higher than in control or sham-operated animals (C). Isolated myocyte dimensions and volume increased in parallel with whole heart hypertrophy and elevation in MAP. However, the relationship between membrane surface area (measured by capacitance) and cell volume (measured by laser scanning confocal microscopy) was unaltered (C: 8.9 +/- 0.3; B: 8.5 +/- 0.4 pF/pl). No differences in the voltage dependence of ICa activation, steady-state inactivation, or recovery from inactivation were detected between C and B myocytes. Maximal ICa density for the two groups was also not different either under basal conditions (C: 4.28 +/- 0.98; B: 4.57 +/- 0.60 pA/pF) or in the presence of 1 microM isoproterenol (C: 16.6 +...Continue Reading

Citations

Jan 9, 2009·American Journal of Physiology. Regulatory, Integrative and Comparative Physiology·Enzo R PorrelloLea M D Delbridge
Dec 24, 2004·American Journal of Physiology. Heart and Circulatory Physiology·Mark R FowlerClive H Orchard
Jun 14, 2000·American Journal of Physiology. Heart and Circulatory Physiology·L J HellerJ R Prohaska
Apr 10, 2007·American Journal of Physiology. Heart and Circulatory Physiology·Taku YamamotoHiroaki Matsubara
Feb 3, 2015·The Journal of Physiology·William E LouchPasi Tavi
Dec 21, 2000·American Journal of Physiology. Heart and Circulatory Physiology·D StilliE Musso
Apr 12, 2002·Physiological Genomics·Stephen B HarrapLeanne M D Delbridge
May 2, 2006·American Journal of Physiology. Heart and Circulatory Physiology·Beatriz M R CarvalhoJosé W M Bassani
Jul 2, 2009·The Journal of Physiology·Sandor GyörkeDmitry Terentyev
Jul 19, 2002·American Journal of Physiology. Heart and Circulatory Physiology·Allison L BayerAllen M Samarel
Sep 29, 1999·Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology·S E AndersonP M Cala

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