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Monitoring of intracellular free Zn 2+ and Ca 2+ changes in cardiomyocytes from metabolic syndrome rats
Author(s) -
Toy Aysegul,
Okatan Esma,
Degirmenci Sinan,
Turan Belma
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.1042.4
Subject(s) - endocrinology , medicine , endoplasmic reticulum , homeostasis , ryanodine receptor 2 , metabolic syndrome , chemistry , intracellular , metabolism , calcium , biochemistry , ryanodine receptor , obesity
Metabolic syndrome (MetS) is the name for a group of risk factors that raises important risk for heart disease and other health problems. The main features of metabolic syndrome include insülin resistance and hypertension. Although evidence is emerging that changes in cardiac energy metabolism might contribute to the development of contractile dysfunction, a depressed sarcoplasmic reticulum (SR) function seems to be a good candidate to underlie MetS‐induced cardiac dysfunction. Therefore, the present study was designed to determine whether the properties of Zn 2+ (with FluoZin‐3 loading) and Ca 2+ (with Fluo‐3 loading) sparks might provide insight into the role of SR in the altered Zn 2+ and Ca 2+ signaling in MetS cardiomyocytes when they were analyzed together with Zn 2+ and Ca 2+ transients. MetS was induced with high‐sucrose drinking water during 16‐week period in male rats. Basal Zn 2+ and Ca 2+ levels as well as frequencies of Zn 2+ and Ca 2+ sparks in cardiomyoctes significantly increased compared to aged‐matched controls. The Ca 2+ transients exhibited significantly reduced amplitude and prolonged time course while no change in amplitude and prolongation in time course of Zn 2+ transients in cardiomyocytes from MetS rats. Spatio‐temporal properties of both Zn 2+ and Ca 2+ sparks were also significantly altered to being almost parallel to the changes of Zn 2+ and Ca 2+ transients. In addition, RyR2 from MetS group was hyperphosphorylated while its protein level was depressed, similar to the hyperphosphorylation of RyR2 with Zn 2+ in a dose‐dependent manner. These data show that cardiomyocytes from MetS rats exhibit altered local Zn 2+ and Ca 2+ signaling with increased basal Zn 2+ and Ca 2+ levels.