ID 111301
Author
Takata, Kaori The University of Tokushima
Keywords
myocardial protection
hyperkalemia
ischemia/reperfusion
cardiotonic steroids
Content Type
Journal Article
Description
Background : Hyperkalemia has multimodal effects on myocardial protection during ischemia/reperfusion. The preservation of Na+/K+-ATPase activity induced by hyperkalemia may have critical impact on myocardial protection. Methods : To elucidate the roles of hyperkalemia (16 mM) and Na+/K+-ATPase inhibition (100 μMouabain) inmyocardial protection during simulated ischemia (5 mM NaCN and 5.5 mM 2-deoxyglucose)/ reperfusion, we measured loss of membrane integrity and bleb formation using a vital dye calcein AM in cultured neonatal rat cardiomyocytes. The control perfusate was switched to treatment solution for 15 min, followed by reperfusion for 30 min. In a second set of experiments, myocardial excitability and diastolic intracellular calcium ion concentration ([Ca2+]i) were measured during a 45-min treatment using a calcium-sensitive fluorescent dye fluo-4 AM. Results : Simulated ischemia/reperfusion under ouabain treatment induced loss of membrane integrity, which was suppressed by hyperkalemia. Simulated ischemia/reperfusion induced bleb formation, which was accelerated by ouabain. Hyperkalemia delayed and inhibited the increase in diastolic [Ca2+]i induced by simulated ischemia. Furthermore, hyperkalemia almost completely inhibited the effects of ouabain on the diastolic [Ca2+]i during ischemia. Conclusions : These results suggest that hyperkalemia during ischemia is cardioprotective against ischemia/reperfusion insults and that hyperkalemia inhibits the effects of ouabain during ischemia.
Journal Title
The Journal of Medical Investigation
ISSN
13496867
13431420
NCID
AA11166929
AA12022913
Publisher
Faculty of Medicine Tokushima University
Volume
60
Issue
1-2
Start Page
66
End Page
76
Sort Key
66
Published Date
2013-02
EDB ID
DOI (Published Version)
URL ( Publisher's Version )
FullText File
language
eng
TextVersion
Publisher
departments
University Hospital
Medical Sciences