Objective: To observe the effect of acupuncture on hemorheology and cerebral nitric oxide synthase(NOS) activity and nitric oxide(NO) content in vascular dementia(VD) rats.Methods: A total of 36 Wistar rats were evenly and randomly divided into control

model

acupuncture and medication groups.VD model was established by using 2-vascular occlusion method."Baihui"(GV 20) and "Dazhui"(GV 14) were punctured with the needles manipulated for 5 min and retained for 30 min

once daily

4 weeks altogether.Rats of medication group were fed with Piracotum(20 mg/mL)

once daily

4 weeks altogether.The rats' learning and memory ability was tested by using shuttle box(passive and active avoidance) test.At the end of the study

blood samples were collected by extracting out the eyeball for detecting whole blood viscosity(WBV)

plasma viscosity(PV)

hematocrit and fibrinogen content separately

and the brain tissues(except brainstem and cerebella) were taken out to be processed into homogenate for detecting NOS activity and NO content with colorimetric method.Results: Before operation

there were no significant differences among the 4 groups in the times and duration of electric shock

and after operation

the electric shock times and duration of model group increased significantly compared with control group(P<0.05) and with pre-operation in the same group(P<0.001).Compared with model group

the electric shock times and duration of acupuncture and medication groups decreased considerably after operation(P<0.01)

suggesting an improvement of the VD rats' learning-memory ability.In comparison with control group

cerebral NO content and NOS activity increased markedly(P<0.001)

and compared with model group

these two indexes of acupuncture and medication groups lowered significantly(P<0.05) in spite of being higher than those of control group(P<0.05).No significant differences were found between acupuncture and medication groups in the abovementioned 4 indexes(P>0.05).Compared with control group

the values of high

medium and lower shear rates

PV

hematocrit and fibrinogen in model group were all markedly higher(P<0.05

0.001)

while in comparison with model group

these six indexes of acupuncture group declines significantly(P<0.05

0.01) despite of being significantly higher than those of control group(P<0.05).No significant differences were found between medication and model group in the aforementioned six indexes of hemorheology(P>0.05).It indicated that acupuncture could improve hemorheology in VD rats

while medication had no significant effect.Conclusion: Acupuncture of GV 20 and GV 14 can improve the learning and memory ability

reduce cerebral NOS activity and NO content

and improve hemorheology in VD rats.