Objective: To research the effect of preventative moxibustion(PM) of "Guanyuan"(CV 4) on nitric oxide synthase(NOS) activity in the plasma and uterus tissue in menopausal rats.Methods: A total of 70 female SD rats(aged 10 months) were randomized into 10-months(mo) control(con)

12-mo-con

14-mo-con and 16-mo-con

12-moPM

14-mo-PM and 16-mo-PM groups with 10 rats in each group.In addition

other 10 female SD rats aged 4 mo were used as young-con group.In rats of 3 PM groups

moxibustion(one moxa-cone/time) was applied to "Guanyuan"(CV 4) twice a week

8 weeks altogether.At the end of experiments all the rats were decapitated for collecting blood samples and uterus tissues.NOS activities in plasma and the homogenized uterus tissue supernate were detected with nitrate reductase method.Results: In comparison with young-con group

NOS activities of both plasma and uterus tissue in 14-mo-con group

and those of uterus in 16-mo-con group

14-mo-PM and 16-mo-PM groups decreased significantly((P<0.05

0.01)). Comparison between 14-mo-con and 14-mo-PM groups and between 16-mo-con and 16-mo-PM groups indicated that plasma NOS activity of 14-mo-PM group and uterus NOS activity of 16-mo-PM group were significantly higher than those of the former groups

suggesting that preventive moxibustion could inhibit the decline of NOS levels in blood and uterus tissue.Conclusion: Preventive moxibustion of CV 4 can effectively relieve the decline of plasma and/or uterus NOS levels in menopausal rats.