1. Triiodothyronine concomitantly inhibits calcium overload and postischemic myocardial stunning in diabetic rats
- Author
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Michio Shimabukuro, Tomohiro Asahi, Yoshito Oshiro, Nobuyuki Takasu, Ichiro Komiya, and Hisashi Yoshida
- Subjects
Male ,medicine.medical_specialty ,Ischemia ,Myocardial Reperfusion Injury ,In Vitro Techniques ,General Biochemistry, Genetics and Molecular Biology ,Streptozocin ,Ventricular Function, Left ,Diabetes Mellitus, Experimental ,Rats, Sprague-Dawley ,Random Allocation ,Oxygen Consumption ,Internal medicine ,Diabetes mellitus ,Heart rate ,Medicine ,Animals ,General Pharmacology, Toxicology and Pharmaceutics ,Calcium metabolism ,Myocardial Stunning ,Myocardial stunning ,Triiodothyronine ,Dose-Response Relationship, Drug ,business.industry ,Myocardium ,Stunning ,Hemodynamics ,Heart ,General Medicine ,medicine.disease ,Rats ,Perfusion ,Thyroxine ,Endocrinology ,Blood pressure ,Cardiology ,Calcium ,business - Abstract
Acute effects of triiodothyronine (T3) on postischemic myocardial stunning and intracellular Ca2+ contents were studied in the isolated working hearts of streptozotocin-induced diabetic rats and age-matched controls. After two weeks of diabetes, serum T3 and T4 levels were decreased to 62.5% and 33.9% of control values. Basal preischemic cardiac performance did not differ between diabetic and control rats. In contrast, during reperfusion after 20-min ischemia, diabetic rats exhibited an impaired recovery of heart rate (at 30-min reperfusion 57.5% of baseline vs. control 88.5%), left ventricular (LV) systolic pressure (44.1% vs. 89.5%), and cardiac work (23.1% vs. 66.0%). When 1 and 100 nM T3 was added before ischemia, heart rate was recovered to 77.2% and 81.8% of baseline, LV systolic pressure to 68.3% and 81.9%, and cardiac work to 50.8% and 59.0%, respectively. Diabetic rat hearts showed a higher Ca2+ content in the basal state and a further increase after reperfusion (4.96+/-1.17 vs. control 3.78+/-0.48 micromol/g, p
- Published
- 2001