Work

Cytosolic Free Magnesium Levels in Ischemic Rat Heart

Year: 1989

Type: article

Abstract: Changes in cytosolic free magnesium ion concentration (Mgi) during myocardial ischemia were measured by 19F NMR in perfused rat hearts loaded with fluorine-labeled derivatives of the magnesium chelator o-aminophenol-N,N,O-triacetate. The perfused rat hearts were loaded intracellularly with the appropriate magnesium indicator by perfusion with 200-400 ml of Krebs-Henseleit buffer containing 5 microM acetoxymethyl ester of the indicator. Basal Mgi concentrations measured by three different indicators averaged 0.85 +/- 0.10 mM (n = 9) and showed no correlation with the KD of the indicator used. 31P NMR measurements of the magnesium-dependent shift between alpha- and beta-phosphates of ATP demonstrate that there is no measurable lowering of Mgi during loading with fluorinated o-aminophenol-N,N,O-triacetate. Between 10 and 15 min of ischemia, Mgi rose nearly 3-fold to 2.1 +/- 0.4 mM. This increase in Mgi occurred over the same time course as the decrease in ATP. After 20 min of reperfusion with Krebs-Henseleit buffer, Mgi declined to 1.5 +/- 0.5 mM. This sustained elevation of Mgi above basal levels may inhibit calcium release from sarcoplasmic reticulum, thereby contributing to the well documented impairment of mechanical function that occurs after a reversible period of ischemia.

Source: Journal of Biological Chemistry

DOI: 10.1016/s0021-9258(18)83593-1

Authors: E Murphy, C Steenbergen, L A Levy, B Raju, R E London

Institutions: National Institutes of Health, National Institute of Environmental Health Sciences

Language: English

Topic: Cardiac Ischemia and Reperfusion

Subfield: Pathology and Forensic Medicine

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: hybrid

Estimated APC paid: $3,430