NDLI: The Driving Force of the Na+/Ca2+-Exchanger during Metabolic Inhibition

Content Provider	PubMed Central
Author	Antonius, Baartscheer Schumacher, Cees A. Coronel, Ruben Fiolet, Jan W. T.
Copyright Year	2011
Abstract	Objective: Metabolic inhibition causes a decline in mechanical performance and, if prolonged, myocardial contracture and cell death. The decline in mechanical performance is mainly due to altered intracellular calcium handling, which is under control of the Na+/Ca2+-exchanger (NCX) The driving force of the NCX (ΔG ncx) determines the activity of NCX. The aim of this study was to describe the relation between ΔG ncx and calcium homeostasis during metabolic inhibition. Methods: In left ventricular rabbit myocytes, during metabolic inhibition (2 mmol/L sodium cyanide), sodium ([Na+]i), calcium ([Ca2+;]i), and action potentials were determined with SBFI, indo-1, and the patch clamp technique. Changes of ΔG ncx were calculated. Results: During metabolic inhibition: The first 8 min [Na+]i remained constant, systolic calcium decreased from 532 ± 28 to 82 ± 13 nM, diastolic calcium decreased from 121 ± 12 to 36 ± 10 nM and the sarcoplasmic reticulum (SR) calcium content was depleted for 85 ± 3%. After 8 min [Na+;]i and diastolic calcium started to increase to 30 ± 1.3 mmol/L and 500 ± 31 nM after 30 min respectively. The action potential duration shortened biphasically. In the first 5 min it shortened from 225 ± 12 to 153 ± 11 ms and remained almost constant until it shortened again after 10 min. After 14 min action potential and calcium transients disappeared due to unexcitability of the myocytes. This resulted in an increased of the time average of ΔG ncx from 6.2 ± 0.2 to 7.7 ± 0.3 kJ/mol during the first 3 min, where after it decreased and became negative after about 15 min. Conclusion: Metabolic inhibition caused an early increase of ΔG ncx caused by shortening of the action potential. The increase of ΔG ncx contributed to decrease of diastolic calcium, calcium transient amplitude, SR calcium content, and contractility. The increase of diastolic calcium started after ΔG ncx became lower than under aerobic conditions.
Related Links	http://dx.doi.org/10.3389/fphys.2011.00010
Starting Page	10
File Format	PDF
ISSN	1664042X
e-ISSN	1664042X
Journal	Frontiers in Physiology
Volume Number	2
Language	English
Publisher	Frontiers Research Foundation
Publisher Date	2011-03-11
Access Restriction	Open
Rights Holder	Frontiers Research Foundation
Subject Keyword	Research in Higher Education
Content Type	Text
Resource Type	Article
Subject	Physiology Physiology (medical)

Sl.	Authority	Responsibilities	Communication Details
1	Ministry of Education (GoI), Department of Higher Education	Sanctioning Authority	https://www.education.gov.in/ict-initiatives
2	Indian Institute of Technology Kharagpur	Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project	https://www.iitkgp.ac.in
3	National Digital Library of India Office, Indian Institute of Technology Kharagpur	The administrative and infrastructural headquarters of the project	Dr. B. Sutradhar bsutra@ndl.gov.in
4	Project PI / Joint PI	Principal Investigator and Joint Principal Investigators of the project	Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon
5	Website/Portal (Helpdesk)	Queries regarding NDLI and its services	support@ndl.gov.in
6	Contents and Copyright Issues	Queries related to content curation and copyright issues	content@ndl.gov.in
7	National Digital Library of India Club (NDLI Club)	Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach	clubsupport@ndl.gov.in
8	Digital Preservation Centre (DPC)	Assistance with digitizing and archiving copyright-free printed books	dpc@ndl.gov.in
9	IDR Setup or Support	Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops	idr@ndl.gov.in

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