Enhancement of postischemic myocardial stunning by calcium overload in hearts of diabetic rats.
The effects of Ca2+ concentration on postischemic myocardial stunning were studied in isolated working hearts of rats with streptozotocin-induced diabetes and of age-matched control rats. During reperfusion after 10 min of ischemia, hearts from control rats showed complete recovery of cardiac function of Ca2+ concentrations of 1.25, 1.88, and 2.50 mmol/L, while the recovery of diabetic rats was decreased only at a Ca2+ concentration of 2.50 mmol/L. Although myocardial Na+ and Ca2+ concentrations were comparable between control and diabetic rats, only diabetic rats showed increases in myocardial concentration of Na+ during ischemia and Ca2+ during reperfusion at a Ca2+ concentration of 2.50 mmol/L. Results suggest that diabetic rat hearts are vulnerable to postischemic stunning via an overload of calcium.
Shimabukuro
M
M
Second Department of Internal Medicine, Faculty of Medicine, University of the Ryukyus, Japan.
Higa
S
S
Shinzato
T
T
Nagamine
F
F
Takasu
N
N
D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002908:Chronic Disease; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism / Q000503:physiopathology*; D004305:Dose-Response Relationship, Drug; D006321:Heart / Q000187:drug effects / Q000503:physiopathology; D008297:Male; D017202:Myocardial Ischemia / Q000150:complications* / Q000378:metabolism; D015428:Myocardial Reperfusion Injury / Q000503:physiopathology; D017682:Myocardial Stunning / Q000139:chemically induced / Q000209:etiology*; D009206:Myocardium / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
D002118:Calcium