OBJECTIVE:To investigate antihypertensive effect in rats in order to confirm that twirling reinforcing-reducing manipulation (TRRM) might be the central mechanism underlying the action.METHODS:In the study,18F-2-fluoro-deoxy-D-glucose positron emission tomography (18F-FDG-PET)was employed.Fifity-six spontaneous hypertensive rats (SHRs) were randomly divided into a model group,a single-needle acupuncture (SNA) group,a twirling reinforcing group (SNA + TRF) and a twirling reducing (SNA + TRD) group.Fourteen Wistar rats were assigned to the control group.The acupuncture intervention at Taichong (LR 3) acupoint was administered once daily in the SNA,SNA + TRF and SNA +TRD groups for 14 days,with 1 d interval between the two weeks.The blood pressure (BP) of all rats was measured repeatedly and 18F-FDG-PET scans were conducted on the 14th day.PET images were processed with Statistical Parametric Mapping 8.0.RESULTS:After the intervention,systolic BP showed a significant decrease in the SNA,SNA+TRF and SNA + TRD versus the model groups (all P ＜0.01) and in the SNA + TRF and SNA + TRD versus the SNA groups (both P ＜ 0.01),with the SNA+TRD group exhibited the best antihypertensive effect (P ＜ 0.01).The key brain regions activated by TRRM were mainly concentrated in the cerebellum,hippocampus,hypothalamus,medulla oblongata,insular cortex,midbrain,thalamus and visual cortex.CONCLUTION:TRRM could significantly lower the BP of SHRs by improving the cerebral glucose metabolism of the activated key brain regions and the underlying central mechanism may be related to the central rennin-angiotensin system and neurotransmission.