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Planta Med 2006; 72(7): 621-626
DOI: 10.1055/s-2006-931572
Original Paper
Pharmacology
© Georg Thieme Verlag KG Stuttgart · New York

Astragaloside IV Dilates Aortic Vessels from Normal and Spontaneously Hypertensive Rats through Endothelium-Dependent and Endothelium-Independent Ways

Wei-Dong Zhang1 , 4 , Chuan Zhang1 , Xu-Hui Wang2 , Ping-Jin Gao3 , Ding-Liang Zhu3 , Hong Chen2 , Run-Hui Liu1 , Hui-Liang Li1
  • 1Department of Natural Medicinal Chemistry, School of Pharmacy, Second Military Medical University, Shanghai, P. R. China
  • 2Department of Pharmacology, School of Medicine, Shanghai Jiao Tong University, Shanghai, P. R. China
  • 3Shanghai Institute of Hypertension, Shanghai, P. R. China
  • 4School of Pharmacy, Shanghai Jiao Tong University, Shanghai, P. R. China
Further Information

Publication History

Received: November 1, 2005

Accepted: January 24, 2006

Publication Date:
29 May 2006 (online)

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Abstract

The major active constituent of Astragalus membranaceus, astragaloside IV, has been found to have properties of increasing coronary flow and cardioprotection. In this study, we examined the direct effects of astragaloside IV on vessel dilatation and contraction in isolated aortic rings from both normal and stroke-prone spontaneously hypertensive rats (SHR-SP) in vitro. The results demonstrated that astragaloside IV could antagonize vessel contractions induced by phenylephrine and potassium chloride in a concentration-dependent way. Astragaloside IV reduced CaCl2-induced contractions in Ca2+-free solution. Astragaloside IV also dilated aortic vessels in a dose-dependent manner, which was partially endothelium-dependent through the nitric oxide (NO) and cGMP pathways. The aorta from 6-month-old SHR-SP rats showed impaired endothelium function, and astragaloside IV dilated the vessels from the hypertensive rats to a lesser extent as compared with normal control rats. In the presence of perivascular fat tissue, the contractile responses induced by angiotensin II and phenylephrine were also attenuated by astragaloside IV. Collectively, this study provides functional evidence that astragaloside IV exerts vessel dilatation properties through the endothelium-dependent NO-cGMP pathway in normal and hypertensive rats. It blocks extracellular calcium influx and participates in vessel relaxation partly through phenylephrine and angiotensin II inhibition when perivascular fat is present.

Key words

Astragaloside IV - vasodilatation - endothelium - perivascular fat - hypertension

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Wei-Dong Zhang

Department of Natural Medicinal Chemistry

School of Pharmacy

Second Military Medical University

325 Guohe Rd.

Shanghai 200433

People’s Republic of China

Phone: +86-21-2507-0386

Fax: +86-21-2507-0386

Email: WDZhangY@hotmail.com