Objective: To investigate the specificity of the effects of electroacupuncture (EA) at different acupoints on gastric functional activity and gastric blood flow after colorectal distension (CRD) in the rat. Methods: Fifty Wistar rats were randomly divided into 5 groups: a control group, a Zusanli group, a non-point group, a Taichong group and a Neiguan group. Rats were anesthetized after 18 h of fasting, and a rat model of nociceptive blood pressure elevation and abnormal electrogastrogram (EGG) and gastric tension (GT) was prepared by gasbag-induced CRD. EA was given bilaterally, and its effects on gastric blood flow (GBF) of the arcus vasculosi of the greater omentum, blood pressure, EGG fast wave properties, and gastric smooth muscle tension (GT) were quantified. Results: CRD induced an increase in blood pressure that was significantly inhibited by EA at all points (all P<0.05), and the inhibitory effects were greater in the Zusanli and Neiguan groups compared to the non-point group (both P<0.05). CRD also caused reductions in GT and GBF, and in the amplitude, frequency and duration of EGG waves (all P<0.05). These effects were also reversed by EA. The effects of EA on EGG wave amplitude, GT, and GBF were superior in the Zusanli group compared to the Taichong group, Neiguan group, and the non-point group. Conclusion: EA significantly counteracted CRD-induced changes in blood pressure, GBF, EGG, and GT. The effects of stimulation at Zusanli (ST 36) were significantly greater compared to other points, indicating relative specificity of this acupoint.
Objective: To explore the mechanism of electroacupuncture (EA)-induced cumulative analgesic effects on chronic pain in rats with or without ovariectomy (OVX). Methods: A total of 110 female Wistar rats were randomized into normal control (n=10), chronic constrictive injury (CCI, n=10), CCI+EA (n=30), OVX+CCI (n=30), and OVX+CCI+EA (n=30) groups. Each of the latter 3 groups was further divided into 2 days (2 d), 2 weeks (2 W) and 3 weeks (3 W) subgroups, respectively (n=10 in each subgroup). The CCI pain model was established by ligature of the right sciatic nerve, and the memory impairment model duplicated by OVX. The paw withdrawal latency (PWL, pain threshold) of the bilateral footplates was detected by radiant heat irradiation, and the bilateral difference in PWL (PWLD) was used to evaluate changes in the pain reaction. Morris water maze test was conducted for evaluating the rats' learning-memory ability. EA was applied to bilateral Zusanli (ST36) and Yanglingquan (GB34) for 2 d, 2 W and 3 W, respectively. Pituitary and hypothalamic 13-endorphin (EP) and adrenocorticotrophic hormone (ACTH) contents were detected by immunoradioassay. Results: Compared with the CCI group, PWLD of the CCI+EA-3 W group decreased significantly (P〈0.05). Compared with the OVX+CCI group, PWLD of the OVX+CCI+EA-3 W group was lowered considerably (P〈0.05), but the value was markedly higher than its basal value and those of the normal control and CCI+EA groups (P〈0.05). In comparison with the sham-OVX group, the escape latency, swimming distance (SD) in the target quadrant and total SD were increased remarkably in the OVX group (P〈0.05), while the number of target platform crossings was decreased significantly (P〈0.05), suggesting an impairment of the OVX rats' learning-memory ability. In simple CCI rats, both β-EP and ACTH contents of the pituitary increased markedly (P〈0.05), and those of the hypotha