OBJECTIVETo observe the hypotensive effects of Qindan Capsule (QC) on spontaneous hypertensive rats (SHR) and its effect on the contents of endothelin (ET), calcitonin gene-related peptide (CGRP) and angiotensin-II (Ang-II ) in plasma and vascular tissues, and to investigate the possible mechanism of QC in lowering blood pressure.

METHODSForty SHRs were divided into 5 groups: the high dosage QC group [QCHD, 750 mg/(kgxd)], the low dosage QC group [QCLD, 150 mg/(kgxd) ], the Niuhuang Jiangya Pill group [NJP, 200 mg/(kgxd) ], the Captopril group [ 15 mg/(kg d) land the model group, 8 in each group. Meanwhile, a normal control group consisting of 8 Wistar-Kyoto (WKY) rats was set up also. All the rats were administered with medicine through gastrogavage. Systolic blood pressure (SBP), level of ET, CGRP and Ang-II in plasma and Ang-II in tissues of mesenteric artery were detected in all the rats after 12 weeks of treatment.

RESULTSThe level of SBP after treatment in the QCHD group was lower than that in the model group (P<0.01), but with no significant difference as compared with that in the Captopril group and the NJP group (P>0.05). After treatment, the plasma level of ET was lower and CGRP higher than those in the model group (both P<0.05), and also higher than those in the NJP and Captopril group (both P<0.05). As for the content of Ang-II , in mesenteric arterial tissues, it was lower in the QCHD group than that in the model group ( P<0.05), but in plasma, it showed no significant difference between the two groups (P>0.05).

CONCLUSIONQC has a satisfactory hypotensive action on SHR rats, and its mechanism may be associated with the regulation on plasma vasoactive peptide and regional renin-angiotensin system.