Effect of Aqueous Extract of Polygoni Multiflori Radix on Hypertension and Arterial Contraction in Animal Models

하수오(何首烏)가 고혈압과 수축혈관에 미치는 영향

This research was aimed to examine the effect of Polygoni Multiflori Radix extract on the blood pressure in spontaneous hypertensive rat (SHR) and norepinephrine - induced arterial contraction in rabbit. In order to investigate the effect of Polygoni Multiflori Radix on rabbit's contracted vascular ring detached from common carotid artery, vascular ring with intact or damaged endothelium was used for the experiment using organ bath. To analyze the mechanism of Polygoni Multiflori Radix-induced relaxation, Polygoni Multiflori Radix extract was infused into contracted vascular ring which had been pretreated by $N{\omega}$-nitro-L-arginine(L-NNA), Methylene blue(MB), and $Ca^{2+}$ was infused into contracted vascular ring induced by NE after treatment of Polygoni Multiflori Radix extract in $Ca^{2+}$-free solution. The results were as follows: Systolic blood pressure was significantly attenuated by administration of Polygoni Multiflori Radix. Blood flow and aldosterone were significantly decreased, but velocity and renin were not affected by Polygoni Multiflori Radix. Polygoni Multiflori Radix had an effective relaxation to the contracted vascular ring by NE in 0.03 mg/ml, 0.1 mg/ml and 0.3 mg/ml level. Polygoni Multiflori Radix had an effective relaxation to the intact endothelium vascular ring, but when endothelium was removed, vascular ring did not relax. Polygoni Multiflori Radix-induced relaxation was inhibited by the pretreatment of L-NNA and MB. Pretreatment of Polygoni Multiflori Radix extract inhibit the contraction by influx of extra-$Ca^{2+}$ in contracted vascular ring induced by NE in $Ca^{2+}$-free solution. As mentioned above, we suggest that Polygoni Multiflori Radix relaxes vascular ring through suppress influx of extra-cellular $Ca^{2+}$ by the action of nitric oxide from endothelium.