ABSTRACT
<p><b>OBJECTIVE</b>To study the effect and mechanism of Danhong injection on isolated mesenteric arterial rings in rats.</p><p><b>METHOD</b>An isolated vascular ring experiment was conducted to determine the changes in tension of vascular rings with a biological signal collection and analytical system.</p><p><b>RESULT</b>Danhong injection had no impact on the tension of vascular rings. Danhong injection showed a significant vasodilatation effect on treated arteria rings of norepinephrine, and no remarkable impact was made on the effect without endothium. It showed notable effect on blood vessels treated with Ca(2+) and no significant impact on those treated with caffeine. It could inhibit NE-induced intracellular calcium from releasing and external calcium from inflowing. No effects of potassium channel blockers on aorta ring tensile force were found.</p><p><b>CONCLUSION</b>Danhong injection shows significant vasodilation effect, which mainly works through vascular smooth muscle. Its vasodilation effect may be related to inhibitory receptor, voltage-dependent Ca(2+)-release and IP3 receptor-mediated Ca(2 +)-influx.</p>