The effects of diazepam in cardio depressant concentration on the function of isolated rat heart in ischemia-reperfusion.

OBJECTIVE: To investigate the effects of cardio depressant concentration of diazepam on the function of isolated rat heart in ischemia-reperfusion. METHODS: This study was performed at the Medical Biology Research Center, Kermanshah, Iran from November 2006 to March 2007. Isolated, perfused rat hearts were subjected to 40 minutes normothermic global ischemia and 45 minutes reperfusion. Diazepam (100 microM) was added to the perfusion solution for 10 minutes before ischemia in the test group. Different cardiac variables including left ventricular developed pressure, heart rate, and coronary flow (CF) were measured. Rate pressure product (RPP) was calculated, during the ischemic period time until onset of ischemic contracture and maximum contracture were determined. In reperfusion, released lactate dehydrogenase enzyme in effluent was measured and cardiac functional recovery was determined. RESULTS: It was found that diazepam significantly decreased RPP and increased CF before ischemia. In the diazepam group (n=10), during ischemia, maximum contracture was significantly lower than the control group (n=14). Also, diazepam significantly increased functional recovery and coronary flow in reperfusion. CONCLUSION: Diazepam (100 microM) significantly decreased maximum contracture during ischemia, improved the recovery of myocardial function and CF in reperfusion. The results show that the cardio depressant concentration of diazepam is safe and relatively protective in the ischemia-reperfused isolated rat heart. These effects may be mediated by inhibition of calcium current in cardiomyocytes.