| BackgroundAstragalus membranaceus (AM) is a traditional Chinese medicine. It" s clinical efficiency has been verificated comprehensively in many great prescription of every dynasty. AM has been regarded as a superior drug. So there were so many investigations and discussions about single AM, utility component of AM or the medicine which major agent is AM by now. And these investigations and discussions just start to grow. Modern medicine found that chemistry component of AM was so complicated that it applicated in many diseases, especially in cardiovascular diseases. These effects include anti virus and relieve immunologic reaction to viral myocarditis. The protective effect on myocardial ischemia and hypoxia and striving heart, diuresis and expand blood vessel all has been manifested. The effect of AM on blood pressure has been realized rudimently in the post clinic and animal investigation. The practic of homeland medicine demonstrated that AM could increase blood pressure as a kind-5-drug of "Bu Qi". But it was detected meanwhile that the regulation action of AM on blood pressure was different by dosage or symptom of a disease. So the main opinion of the regulation action of AM on blood pressure is that AM has diphase action. Modern pharmacology experiment has detected that AM has the acute effect on animal blood pressure. Astragalus membranaceus saponin, a ?tyrosine and et al may be the main component of decompression. Expanding blood vessel and inhibiting Ca2+ internal flow are suspected to be related to the decompression action of AM.The advanced investigation demonstrated that AM could decrease significantly the raise of Ca2+ internal flow caused by virus infection. Astragalus membranaceus saponin, utility component of AM, can enhance Sarco/Endoplasmic Ca2+ ATPase and gene expression in mice infected by Coxsackie virus 83.80 that AM is effective to relieve [Ca2+]i and intracellular calcium overload. All of these indicated that AM has the action like calcium channel blocking agent. The extract of AM from water can increase the expression of iNOS mRNA in the cultured vascular smooth muscle cell to affect blood vessel endothelium function. The important premise of blood vessel keeping it's common tension is calcium ions transport stably in vascular smooth muscle cell membrane and intracellular. Investigation has maken it clear that essential hypertension is related to the disorder of calcium ions accommodation. Animal experiment certificated the same phenomenon that intralymphocytes calcium ions level is positively correlated to blood pressure level. Endothelins is the most powerful factor antagonism to NO in contracting blood vessel by now. The balance of ET and NO is the most important premise of vessel to keep normal tension. Endothelins not only has the powerful effect of contracting blood vessel, but also can promote proliferation and accelerate calcium ions internal flow, inhibit the activity of calcium pump and sodium pump. It has already been confirmed that calcium ions and endothelins participate the reconstitution of myocardium interstitial. According to literature, plasma ET level in-6-essential hypertension patients is higher by 2 to 4 times than that in control. The higher blood pressure, the higher plasma ET level is. So the calcium ions overload in cell and the step-up of plasma level of ET have great relationship to the happening of hypertension. LVH in the process of hypertension and the reconstruction of the myocardium interstitial .However, the function of Astragalus membranaceus to regulate blood pressure of SHR (Spontaneously Hypertensive Rats) and relieve LVH and vascular reconstitution in the process of hypertension is not clear , and whether these effects of Astragalus membranaceus related to relieving calcium ions overload and protecting endothelium function.ObjectiveTo illuminate the effect of Astragalus membranaceus on the blood pressure and on decreasing LVH and vascular sclerosis in SHR, and to study the effect on relieving calcium ions ove...
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