| Objective: To study the effects of intravenous injection with YLS on blood pressure (BP), coronary flow (CF), cardiac hemodynamics and myocardial ischemia-reperfusion (MIR) in rats. Methods: (1) Carotid artery catheter and MS2000 multimedia biological signal analysis system were used to observe and record systolic pressure (SP), diastolic pressure (DP) and heart rate (HR) in anesthetized Wistar rats and spontaneously hypertensive rats (SHR) before and at 1/3, 1/2, 1, 2, 5min after YLS intravenously. (2) Isolated rat heart model was used in Assay of CF. (3) Cardiac cannula and MS2000 multimedia biological signal analysis system were used to observe and record left ventricle systemic pressure (LVSP), left ventricle ending diastolic pressure (LVEDP), HR, dp/dtmax, T, Vm, Vp, t-dp/dtmax in anesthetized Wistar rats before and after YLS intravenously. (4) An experimental MIR (Coronary ligation for 5 min followed by reperfusion for 30min.) in Wistar rats was used to determine the area of myocardial ischemia, the activities of superoxide dismutase (SOD), lactate dehydrogenase (LDH) and creatine kinase (CK), and the content of MDA in myocardium or serum following the treatment with YLS. Results: The results showed that: (1) YLS could significantly decrease the blood pressure and heart rates in Wistar rats and SHR. Its antihypertensive effect was short, usually returned to the original level of BP at 2min after the administration of YLS. In addition, YLS did not influence the effects of norepinephrine and isoproterenol. (2) YLS could significantly increase CF in isolated rat heart. (3) YLS could significantly decrease LVSP, HR and dp/dtmax(P<0.01 or P<0.05) but not influence LVEDP, t_dp/dtmax and -dp/dtmax.(4) YLS could not only significantly decrease the content of MDA and the activity of CK-MB as well as markedly reduce the area of myocardial ischemia and increase the activity of SOD (/><0.01 or /><0.05). Conclusion: YLS has the significant effects of antihypertension, inhibition of myocardial contractility, decrease in HR, increase in CF and myocardial protection. |
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