Vasorelaxation Effect of Gastrodin on Isolated Thoracic Aorta Rings of Rats

Objective： To study the effect of gastrodin on isolated thoracic aorta rings of rats and to investigate the potential mechanism. Methods： A perfusion model of isolated thoracic aorta rings of rats was applied. The effect of cumulative gastrodin （5, 50, 100,150, 200, and 250 μ mol/L） on endothelium-intact aorta rings was investigated. The same procedure was applied to observe the effect of gastrodin on endotheliumintact/denuded aorta rings pre-contracted with 10.8 mol/L phenylephrine hydrochloride （PE）. The aorta rings incubated by 200 mmol/L gastrodin in the Ca2＋-free （K-H） solution was contracted by using PE. The effect of 200 mmol/L gastrodin on endothelium-denuded aorta rings pre-contracted with 60 mmol/L KCI was also observed. Results： Compared with the denuded gastrodin group, the intact gastrodin group could significantly relax the PE-contracted aorta rings （P〈0.01）. In Ca2＋-free （K-H） solution KHS, the PE-induced contraction rate of aorta rings pre-incubated by gastrodin was 6.5%± 0.7%, which was significantly less than the control group （11.8% ± 0.9%, P〈0.01）. However, after 3 mmol/L CaCl2 was added, the Ca2＋-induced contraction in the gastrodin group （51.7% ±2.4%） was similar to that in the control group （49.8% ± 2.8%）. The contractile rate of rings in the KCI-contracted gastrodin group （96.3%± 0.6%） was not significantly different from that in the control group （96.8± 1.2%）. Conclusions： Gastrodin has the effect of vasorelaxation on isolated thoracic aorta rings of rats. The mechanism of the vasorelaxation of gastrodin may mainly work through the inhibition of inositol 1,4, 5-trisphosphosphate receptor on the sarcoplasmic reticulum of the arterial smooth muscle, which leads to the reduction of the Ca2. released from the sarcoplasmic reticulum.