ABSTRACT
To evaluate whether repeated diazepam administration affects the heart in ischemia- reperfusion. This study was performed at the Medical Biology Research Center, Kermanshah, Iran, from March to September 2008. Four groups of rats were subjected to a daily injection of diazepam [group 1 [0.5 mg/kg for 21 days], group II [2.5 mg/kg for 5 days], and group III [5 mg/kg for 5 days] intraperitoneally], and saline solution [21 days] in the control groups. Isolated, perfused hearts were subjected to 40 minutes global ischemia, and 45 minutes reperfusion. The left ventricular developed pressure [LVDP], heart rate, and coronary flow were measured. Rate pressure product [RPP] was calculated. In reperfusion, released lactate dehydrogenase [LDH] enzyme in effluent was measured. It was observed that the recovery of the RPP and LVDP in reperfusion significantly decreased in the test group III [n=9] in comparison to the control [n=8]. During the reperfusion period, the released LDH significantly increased in test group II [n=8] and group III in comparison with the control. The results show that repeated administration of diazepam [5 mg/kg for 5 days] reduced the cardiac performance in reperfusion, and significantly exacerbated the ischemia-reperfusion injury. It is probably mediated by the changing of cardiac susceptibility in ischemia due to repeated administration of diazepam