| 摘要: | 中文摘要
Apocynum venetum羅布麻在中國用來當作單方的抗高血壓茶。
在先前大鼠離體主動脈血管研究，顯示羅布麻葉萃取物 (AVLE) 會引起大鼠主動脈血管內皮依存性舒張的作用。但本研究室發現高劑量之AVLE反而會引起之血管收縮作用。所以本研究希望探索AVLE對離體大鼠主動脈之血管舒張與收縮截然不同張力的機理，希望釐清羅布麻用來抗高血壓茶的作用評估。投與低劑量AVLE 10 g/ml能引起作用時間長的內皮依存性之血管舒張作用，其血管舒張作用，能被L-NAME (一氧化氮合成酶抑制劑)所逆轉。而高劑量30 g/ml 以上之 AVLE，能逆轉低劑量AVLE產生的長時間血管舒張作用，此現象能被併用之超氧化物歧化酶 (SOD)和過氧化氫歧化酶 (catalase)所抑制。綜合本研究結果推測：在離體大鼠主動脈血管中，低劑量AVLE之血管舒張作用與血管內皮依存性NO產生有關。高劑量AVLE使血管逆轉其舒張作用，可能與產生超氧陰離子 (superoxide anions)有關。
Key words: 羅布麻，AVLE, 抗高血壓茶，主動脈，血管內皮依存性舒張，血管收縮， L-NAME, SOD, catalase, NO, 超氧陰離子。
Abstract
Apocynum venetum, also known as luobuma, has been used as the sole ingredient in antihypertensive tea in China. In our preliminary study, we found Apocynum venetum leaf extract (AVLE) could elicit vasorelaxation but at high dosage of AVLE could reverse the AVLE- evoked vasorelaxation. In this study, we investigate the vascular tension effect of this herb extract in isolated rat thoracic aorta. AVLE 10 g/ml and carbachol (CCh) could elicit endothelium- dependent vasorelaxation. AVLE has shown the long-lasting vasodilatation which that effect could inhibit the phenylephrine (α1-adrenergic receptor agonist; PE)-evoked vasoconstriction but could not inhibit potassium cholride-evoked vasoconstriction. The AVLE-evoked long-lasting vasodilatation could be reversed by L-NAME (nitric oxide synthase inhibitor). The concentration above AVLE 30 g/ml (high dosage) could reverse AVLE evoked long-lasting vasorelaxation. Combined SOD and catalase could inhibit the reverse AVLE evoked vasorelaxation, but less inhibits effect by catalase only. In summary, our results indicate the mechanism of relaxative effect on vascular muscle might be related to endothelium-dependent NO mediated and the high dosage of AVLE evoked vasoconstriction might be mediated by superoxide anions in isolated rat aorta.
Key words: luobuma, AVLE, antihypertensive tea, aorta, EDRF, vasoconstriction, L-NAME, SOD, catalase, NO, superoxide anions. |
