Effects of selenium on altered mechanical and electrical cardiac activities of diabetic rat.
Since selenium compounds can restore some metabolic parameters and structural alterations of diabetic rat heart, we were tempted to investigate whether these beneficial effects extend to the diabetic rat cardiac dysfunctions. Diabetes was induced by streptozotocin (50mg/kg body weight) and rats were then treated with sodium selenite (5 micromol/kg body weight/day) for four weeks. Electrically stimulated isometric contraction and intracellular action potential in isolated papillary muscle strips and transient (I(to)) and steady state (I(ss)) outward K(+) currents in isolated cardiomyocytes were recorded. Sodium selenite treatment could reverse the prolongation in both action potential duration and twitch duration of the diabetic rats, and also cause significant increases in the diminished amplitudes of the two K(+) currents. Treatment of rats with sodium selenite also markedly increased the depressed acid-soluble sulfhydryl levels of the hearts. Our data suggest that the beneficial effects of sodium selenite treatment on the mechanical and electrical activities of the diabetic rat heart appear to be due to the restoration of the diminished K(+) currents, partially, related to the restoration of the cell glutathione redox cycle.
Ayaz
Murat
M
Department of Biophysics, Faculty of Medicine, Ankara University, 06100 Ankara, Turkey.
Ozdemir
Semir
S
Ugur
Mehmet
M
Vassort
Guy
G
Turan
Belma
B
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism; D001835:Body Weight; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy / Q000378:metabolism / Q000503:physiopathology*; D025802:Electric Capacitance; D004558:Electric Stimulation; D004594:Electrophysiology; D005260:Female; D006321:Heart / Q000187:drug effects* / Q000503:physiopathology; D007328:Insulin / Q000097:blood; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects* / Q000502:physiology; D009206:Myocardium / Q000378:metabolism; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000502:physiology; D010210:Papillary Muscles / Q000187:drug effects / Q000502:physiology; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D018038:Sodium Selenite / Q000494:pharmacology*
D001786:Blood Glucose; D007328:Insulin; D015221:Potassium Channels; D018038:Sodium Selenite