[Effect of moderate acupuncture-stimulation of "Taichong" (LR 3) on blood pressure and plasma endothelin-1 levels in spontaneous hypertension rats].

Objective: To observe the effect of different strength of acupuncture stimulation on blood pressure and plasma endothelin (E)-1 in spontaneous hypertension rats (SHR) ,so as to seek a better acupuncture parameter for clinical treatment of hypertension.
Methods: Twenty-eight 9-week-old SHRs were randomized into mild-stimulation group, moderate-stimulation group, strong-stimulation group and model group (n = 7 in each group). Seven normotensive SD rats served as a normal control group. Acupuncture stimulation with mild, moderate and strong stimulation was applied to bilateral "Taichong" (LR 3) for 5 min, once daily for 7 days. Blood pressure (BP) was determined by using a non-invasive BP-6 detection system. Plasma ET-1 was assayed by radioimmunoassay.
Results: Compared with the model group, the systolic pressure of the moderate-stimulation group on the 6th and 7th day was decreased significantly after acupuncture of "Taichong" (LR 3) (P<0. 01), being significantly lower than that of the mild- and strong-stimulation groups (P<0. 01). In comparison with the normal control group, plasma ET-1 level in the model group was increased significantly (P<0.01), while compared with the model group, only that in the moderate-stimulation group was down-regulated considerably (P<0. 01). No significant differences were found between the mild-stimulation and model groups, between the strong-stimulation and model groups, and between the mild-stimulation and strong-stimulation groups in plasma ET-1 level (P>0. 05).
Conclusion: Moderate-stimulation of "Taichong" (LR 3) can lower blood pressure and plasma EA-1 level in spontaneous hypertension rats. The reduced level of plasma ET-1 may be one of its mechanisms underlying improving hypertension.