The present study was carried out to compare the effect of nicorandil and minoxidil (potassium channel openers) versus trimetazidine (cytoprotective drug) on acute myocardial infarction (AMI) induced by isoprenaline in experimental albino rats. The rats were classified into 5 equal groups (6 rats in each group). 1st group (control group) was injected with normal saline s.c. AMI was induced in all other groups by isoprenaline (500 mg/kg, s.c.). 2nd group was not pre-treated, 3rd group was pre-treated with nicorandil (3 mg/kg, i.p.), 4th group was pretreated with minoxidil (3 mg/kg, i.p.) and 5th group was pretreated with trimetazidine (3 mg/kg, i.p.). All drugs were injected 30 minutes before isoprenaline. All these groups were subjected to ECG, measurement of serum CPK-MB fraction and histopathological study for left ventricle, 4 hours after isoprenaline. Data obtained in the present study pointed out that pretreatment with either nicorandil or trimetazidine in isoprenaline-induced AMI produced significant improvement in T-wave voltage, CPK-MB fraction and histopathology. However, nicorandil was more effective than trimetazidine. On the other hand, minoxidil pretreated group showed insignificant changes from non-pretreated group. In conclusion, nicorandil pretreatment is highly protective against isoprenaline induced AMI in rats. It decrease heart rate and that may help to decrease cardiac work and avoid tachyarrhythmia. Trimetazidine produced good protective actions against isoprenaline induced AMI. On the other hand, minoxidil pretreatment lacked any protective effect and participated in more deterioration of AMI |
