Non-steady-state calcium handling in failing hearts from the spontaneously hypertensive rat

Ward, Marie-Louise, Crossman, David J, Loiselle, Denis S and Cannell, Mark B (2010) Non-steady-state calcium handling in failing hearts from the spontaneously hypertensive rat. Pflügers Archiv European Journal of Physiology, 460 (6). pp. 991-1001. ISSN 0031-6768

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Abstract

It is generally agreed that changes in Ca(2+) cycling are often associated with heart failure, yet the impact of these changes on a beat-to-beat basis remains unclear. Measurements of isometric force and [Ca(2+)](i) were made at 37°C in left ventricular trabeculae from failing spontaneously hypertensive rat (SHR) hearts, and their normotensive Wistar-Kyoto (WKY) controls. At 1 Hz, peak stress was reduced in SHR (14.5 ± 2.4 mN mm(-2) versus 22.5 ± 6.7 mN mm⁻² for WKY), although the Ca(2+) transients were bigger (peak [Ca(2+)](i) 0.60 ± 0.08 μM versus 0.38 ± 0.03 μM for WKY) with a slower decay of fluorescence (time constant 0.105 ± 0.005 s versus 0.093 ± 0.002 s for WKY). To probe dynamic Ca(2+) cycling, two experimental protocols were used to potentiate force: (1) an interval of 30 s rest, and (2) a 30-s train of paired-pulses, and the recirculation fraction (RF) calculated for recovery to steady-state. No difference was found between rat strains for RF calculated from either peak force or Ca(2+), although the RF was dependent on potentiation protocol. Since SR uptake is slower in SHR, the lack of change in RF must be due to a parallel decrease in trans-sarcolemmal Ca(2+) extrusion. This view was supported by a slower decay of caffeine-induced Ca(2+) transients in SHR trabeculae. Confocal analysis of LV free wall showed t-tubules were distorted in SHR myocytes, with reduced intensity of NCX and SERCA2a labelling in comparison to WKY.

Item Type:	Article
Uncontrolled Keywords:	animals,calcium,heart failure,heart ventricles,myocardial contraction,rats,rats, inbred shr,rats, inbred wky,sarcolemma,sarcoplasmic reticulum,sarcoplasmic reticulum calcium-transporting atpases,sodium-calcium exchanger
Faculty \ School:	Faculty of Medicine and Health Sciences > Norwich Medical School
UEA Research Groups:	Faculty of Medicine and Health Sciences > Research Groups > Norwich Clinical Trials Unit
Depositing User:	Pure Connector
Date Deposited:	20 Jan 2014 16:04
Last Modified:	24 Oct 2022 05:34
URI:	https://ueaeprints.uea.ac.uk/id/eprint/46192
DOI:	10.1007/s00424-010-0876-3

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