[Effect of adenosine on electrophysiological changes of ventricular myocardium in rats with experimental diabetes].
To investigate the electrophysiological changes of ventricular myocardium of rats with experimental diabetes and the effect of adenosine on its electrophysiology.



Diabetes was induced in male SD rats, using a single injection of alloxan into tail vein. Untreated animals were used as controls. The electrocardiograms (ECG) were recorded 6 weeks after diabetes was induced. Effects of adenosine on ventricular myocardium in diabetic rats and controls were observed by measuring the transmembrane potentials with conventional glass microelectrodes.



QT interval in ECG and action potential duration (APD) at all levels (APD30, APD50, APD70 and APD90) were significantly prolonged in right ventricular papillary muscle 6 week after diabetes was induced. No differences were observed in the resting membrane potential (RP), action potential amplitude (APA) and overshoot (OS) as well as the maximum rate of depolarization (Vmax) between the diabetic rats and control rats. At concentration of 10 approximately 400 micromol/L, ADO had little influence on all transmembrane potential parameters of right ventricular papillary muscle in diabetic rats and controls. At 500 micromol/L, ADO shortened APD30, APD50, APD70 and APD90 of control group, while having no effect on diabetic rats.



QT interval in ECG and APD at all levels are significantly prolonged in right ventricular papillary muscle of experimentally induced-diabetic rats.
Department of Cardiology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, China.
Zhang-qiang
ZQ
Chen
Shen-jiang
SJ
Hu
Qiang
Q
Xia
Yu-liang
YL
Shen
D000200:Action Potentials / Q000187:drug effects; D000241:Adenosine / Q000494:pharmacology*; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology*; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology*; D004562:Electrocardiography; D004594:Electrophysiology; D008297:Male; D010210:Papillary Muscles / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D016276:Ventricular Function
D000889:Anti-Arrhythmia Agents; D000241:Adenosine