文本框: EFFECTS OF ASTRAGALOSIDE IV (XGA) ON MYOCARDIAL CALCIUM TRANSPORT AND CARDIAC FUNCTION OF ISCHEMIC RATS LI Zipu, CAO Qian Affiliated Hospital of Qingdao University Medical College, Qingdao, China Objective: To explore the effects of XGA on myocardial calcium transport and cardiac function of ischemic rats Methods: Eighty-four Wistar rats were divided into three groups: control，ischemic, and XGA（n=60）group. The dose- and time-effect relationship between XGA on myocardial calcium transport, and cardiac function of ischemic rats were studied. Results: With the increase of dose of XGA (2.5, 5.0, 10.0, 15.0, 20.0 mg/kg), the remarkable increase of artery pressure (AP), cardiac output (CO), stroke volume (SV), left and right ventricular systolic pressure (LVSP and RVSP), the maximal rise and decline rate of intraventricular pressure (±dp/dt), and the activity of Ca-pump in ischemic rats were found.; but the left and right ventricular end-diastolic pressure (LVEDP and RVEDP), heart rate(HR) , ionized calcium of the myocardium (MyoCai), and total calcium of the myocardium (MyoCat) declined. At the XGA dose of 5mg/kg , the remarkable increase of AP , CO, SV, LVSP , RVSP, ±dp/dt , and the activity of Ca-pump in ischemic rats with the prolongation of action time(0, 0.5, 1.0, 1.5, 2.0h) were found.; and the decline of LVEDP , RVEDP, HR, MyoCai were also noticed. Conclusion: The effects of XGA improving the cardiac function of ischemic rats increased with the increasing of the dose and the action time of XGA, and the reduction of excessive accumulation of intracellular calcium within myocardial cells may be played an important role. 0698