The effects of hydroxysafflor yellow A on blood pressure and cardiac function

Aim of the study: This work aims to investigate the effects of HSYA on cardiac function and blood pressure. Materials and methods: To evaluate changes in mean arterial pressure (MAP) and heart rate (HR), different groups of pentobarbitone-anesthetized normotensive and spontaneously hypertensive rats (SHR) were treated with intravenous HSYA (0.1-3 mg/kg). Isolated WKY rat hearts in Langendorff system were employed for examining the effect of HSYA on hemodynamic. After 30 min equilibration time the isolated hearts were perfused with HSYA (30 mu mol/L) in a stepwise fashion. Potassium channel inhibitors were used to determine the role of potassium channel activation in HSYA effect. Results: Intravenous injection of the HSYA significantly reduced MAP and HR in both normotensive rats and SHR in a dose-dependent manner. HSYA reduced left ventricular systolic pressure (LVSP), left ventricular end-diastolic pressure (LVEDP), the maximum rate of increase of left ventricular pressure (+dp/dt(max)) and heart rate (HR) in a dose-dependent manner. HSYA had no remarkable effect on the maximum rate of decrease of left ventricular pressure ( -dp/dt(max)); BKCa and K-ATP blocker can weakened the inhibitory effect of HSYA on heart function and HR, but K-V and K-ACh blocker did not significantly weaken the HSYA effects. Conclusion: Our results show that HSYA could significantly reduce blood pressure and heart rate, which may be related to activation of BKCa and K-ATP channels. (C) 2011 Elsevier Ireland Ltd. All rights reserved.