AIM: To explore the effects of astragaloside IV (XGA) on myocardial calcium transport and cardiac function inischemic rats. METHODS: Eighty-four Wistar rats were divided into three groups: control group (n=12); ischemicgroup (n=12) was given isoprenaline injection sc at a dose of 30 mg/kg; and XGA group (n=60) was given XGAafter isoprenaline administration. The changes of the parameters of hemodynamics, cardiac function, and intra-and extracellular calcium concentration of the myocardial cells were determined. The dose- and time-effect rela-tionship of XGA on myocardial calcium transport and cardiac function were observed. RESULTS: After XGAadministration, there was significant improvement in cardiac function and hemodynamics in ischemic rats. Thecardiac output, heart rate, stroke volume, mean aortic pressure, systolic aortic pressure, the stroke work of leftventricule, the right and left ventricle systolic pressure, and +dp/dt of the right ventricle of ischemic rats graduallyrecovered to the level of the control group with increasing the dose of XGA and prolongation of the action of XGA.The ionized calcium of the myocardium and the total amount of calcium of the myocardial tissue decreased mark-edly compared to those in ischemic group, and the activity of calcium pump of erythrocyte membrane increasedsignificantly in comparison to that of ischemic group, but their changes had no trend of increase with increasingdose of the XGA. However, there was a gradual decrease of the ionized calcium of the myocardium with theprolongation of acting time of XGA. CONCLUSION: XGA improves the cardiac function in ischemic rats, and thereduction of excessive accumulation of intracellular calcium within myocardial cells plays an important role.
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