The aim of this study was to investigate the influence of Astragalus membranaceus on the anti-hypertensive effect of ？HHH]-blocker drug, such as atenolol, in spontaneously hypertensive rats. In this study, the short- and long-term influences were determined. The spontaneously hypertensive rats were chosen to simulate the development of hypertension. The influences of the extraction of Astragalus membranaceus, and ？HHH？HH？HH-aminobutyric acid (a chemical compound of Astragalus membranaceus), on the short- and long-term effects of atenolol in SHR and WKY were observed. In addition, to further clarify the mechanisms involved, the vascular reactivity determination, the plasma nitrate and MCP-1levels, the superoxide production of aorta, and the eNOS (endothelial nitric oxide synthase) and iNOS (inducible nitric oxide synthase) expression of aorta, were investigated. We believe this study will be contributive to clarify the pharmacological effects of Astragalus membranaceus and ？HHH？HH？HH-aminobutyric acid. Moreover, the interactions between Astragalus membranaceus and atemolol will be further comprehended.
