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Background Cumulated evidence reveals that glial cells in the spinal cord play an important role in the development of chronic neuropathic pain and are also complicated in the analgesic effect of EA intervention. But the roles of microgliacytes and astrocytes of spinal cord in the process of EA analgesia remain unknown. Methods A total of 120 male Wistar rats were used in the present study. The neuropathic pain model was established by chronic constrictive injury (CCI) of the sciatic nerve. The rats were randomly divided into sham group, CCI group, and sham CCI + EA group, and CCI + EA group. EA was applied to bilateral Zusanli (ST36)-Yanlingquan (GB34). The mechanical (both time and force responses) and thermal pain thresholds (PTs) of the bilateral hind-paws were measured. The number of microgliacytes and activity of astrocytes in the dorsal horns (DHs) of lumbar spinal cord (L4–5) were examined by immunofluorescence staining, and the expression of glial fibrillary acidic protein (GFAP) protein was detected by western blot. Results Following CCI, both mechanical and thermal PTs of the ipsilateral hind-paw were significantly decreased beginning from the 3rd day after surgery (P

To observe the effect of electroacupuncture (EA) on expression of synaptic plasticity-related glutamate N-methyl-D-aspartate (NMDA) receptor subunit NR 1, gamma-aminobutyric acid (GABA) receptor subunits (Aβ 2, B 1), etc. in the amygdala in chronic neuropathic pain negative affection (CNPPNA) rats, so as to reveal its mechanism underlying pain relief.Male Wistar rats were randomized into normal control, CNPPNA model, EA, and anesthesia+EA (AEA)groups (After modeling, PWL difference (PWLD) values of the model group were significantly increased (Repeated EA stimulation of ST 36-GB 34 has a role in relieving both sensory and affection dimensions of chronic pain in CNPPNA rats, which Feb be respectively related to its effects in up-regulating the expression of GABAAβ 2, GABAB 1, NMDA-NR 1, PSD-95 and Piccolo genes, and in promoting the expression of mGluR 1 and GABAB 2 proteins and Piccolo gene in the amygdala.

To observe the effect of electroacupuncture (EA) stimulation of "Neiguan" (PC 6)-"Jianshi" (PC 7) on ischemic myocardial injury in myocardial ischemic (MI) rats, so as to explore its mechanism underlying improvement of MI.A total of 48 male Wistar rats were randomly divided into normal, MI model, PC 6-PC 7, Sanyinjiao-Diji (SP 6-SP 8) groups (Compared with the normal group, the ECG J-point height (1 h), serum CK-MB, LDH 1 and ET contents (1 d and 3 d), HR (1 h and 1 d) and LF/HF levels of HRV (1 h, 1 d and 3 d) and the number ofEA intervention may improve ischemic myocardial injury in MI rats, probably by activating neurons in the NA region, and enhancing the cardiac parasympathetic tension, and balancing cardiac sympathetic/parasympathetic nerve activities, but the effect of cholinergic neurons of NA needs being studied further.

Increasing evidence has been accumulated for the effectiveness of acupuncture therapy in relieving pain. However, there are limited data on regulation of protein expression after electroacupuncture (EA) intervention. Thus, the present study is designed to determine changes in protein expression following EA stimulation in rats with sciatic nerve chronic constrictive injury (CCI) induced neuropathic pain. Sixty Wistar rats were equally randomized into normal control group, CCI group, and CCI with EA stimulation (EA) group. The CCI model was established by ligature of the left sciatic nerve. EA stimulation was applied at Zusanli (ST36) and Yanglingquan (GB34) in the EA group. Differentially expressed hypothalamic proteins in the three groups were identified by 2-D gel electrophoresis and matrix-assisted laser desorption/ionization time of flight mass spectrometry. The functional clustering and pathway of the identified proteins were analyzed by Mascot software. Results showed that, after CCI, the thermal pain threshold of the affected hind footpad was decreased and was reversed gradually by 12 sessions of EA treatment. Following EA intervention, there were 17 hypothalamic proteins identified with significant changes in the expression (>twofold). Three gene-ontologies (oxidoreductase activity, oxidation reduction, and protein binding) were enriched, while there was a significant regulation of glycolysis/gluconeogenesis/hexose metabolism pathway. These data demonstrate that EA intervention can attenuate pain via regulation of expression of multiple proteins in the hypothalamus. Further, hypothalamic glucose metabolism may be important in supporting energy and neurotransmitter homeostasis in the effects of EA intervention.

To observe the effect of electroacupuncture (EA) on expression of pain sensory and affective processing-related µ-opioid receptor (MOR), glutamatergic AMPA receptor subunit GIuA 1, extracellular signal-regulated kinase (ERK 1/2), cAMP response element binding protein(CREB) in the amygdala in chronic constrictive injury (CC) + negative affection(NA) rats, so as to reveal its mechanism underlying pain relief.A total of 32 male Wistar rats were randomized into normal control, model, EA, and anesthesia+ EA (AEA) groups (n = 8 in each group). The neuropathic pain NA model was established by ligation of the left sciatic nerve and repeated electrical stimulation of the paw-bottom in the pain-paired compartment. EA was applied to bilateral "Zusanli" (ST 36) and "Yanglingquan" (GB 34) for 30 min, once daily for 7 days. Thermal pain threshold (paw withdrawl latency, PWL) of the bilateral paws was measured by using a Tail-Flick Unit. The expression levels of MOR and p-CREB in the central amygdala (CeA) and those of MOR, GluA 1, p-ERK 1/2 and p-CREB in the right amygdala area were determined using immunofluorescence and Western blot, respectively.in comparison with the normal group, PWL difference (PWLD) values of the model group were significantly increased (P0.001), and the time spent in the CPA-paired. compartment was considerably decreased (P0.001). After EA, the PWLD levels of both EA and AEA groups were apparently decreased (P0.05), showing a pain relief; and the time spent in the CPA-paired compartment was apparently increased in the EA group (P0.05) , rather than in the AEA group (P0.05). Additionally , compared to the normal group, the expression level of MOR protein in the amygdala was remarkably increased (P0.05) and those of GIuA 1, p-ERK 2 and p-CREB proteins were apparently decreased (P0.05). After EA intervention for 7 days, the expression levels of these four proteins in the EA group, and those of MOR, p-ERK 2 and p-CREB in the AEA group were significantly up-regulated (P0.001, P0.01, P0.05). The expression level of GIuA 1 was significantly higher in the EA group than in the AEA group (P0.05).Repeated EA stimulation of ST 36-GB 34 has a definite effect in relieving both sensation and affection dimensions of pain in NA rats, which may be related to its effect in up-regulating the expression of GIuA 1 in the amygdala, but the effects of MOR, p-ERK 2 and p-CREB need being researched further.

To observe the effects of repeated electroacupuncture (EA) of Zusanli (ST36)- Yanglingquan (GB34) on hypothalamic acetylcholinesterase (AchE) and vesicular acetylcholine (ACh) transporter (VAChT) activities and choline acetyltransferase (ChAT) mRNA and muscarinic M1 receptor (M1R) mRNA expression in chronic constrictive injury (CCI) and/or ovariectomy (OVX) rats so as to reveal its underlying mechanism in cumulative analgesia.A total of 103 female Wistar rats were randomly divided into normal control (n =15), CCI (n =15), CCI+EA2d (n =15), CCI+EA2W (n =15), OVX+CCI =13), OVX+CCI+EA2d (n =15), and OVX+CCI+EA2W groups (n =15). CCI model was established by ligature of the unilateral sciatic nerve with surgical suture. Memory impairment model was established by removal of the bilateral ovaries. Morris water test was conducted to evaluate the OVX rats' memory learning ability, and the thermal pain threshold (PT) of the bilateral paws was detected the next morning after EA. EA (2/15 Hz, 1 mA) was applied to bilateral ST36-GB34 for 30 min, once daily for 2 days or 2 weeks, respectively. Hypothalamic AChE activity was detected by histochemistry, VAChT immunoactivity was determined by immunohistochemistry, and ChAT mRNA and M1R mRNA expressions were assayed by reverse transcription-polymerase chain reaction (RT-PCR).In comparison with the normal control group, the AChE activity in hypothalamic arcuate nucleus (ARC) and supraoptic nucleus (SON) regions of CCI group, AChE activity in paraventricular nucleus (PVN), ARC, and SON regions of OVX+CCI group, and hypothalamic muscarinic M1R mRNA expression levels in both CCI and OVX+CCI groups were down-regulated significantly (P0.05). Compared with the CCI group, the AChE activities in hypothalamic ARC and SON regions of CCI+EA2d and CCI+EA2W groups and PVN region of CCI+EA2W group and hypothalamic ChAT mRNA and M1R mRNA expression levels in CCI+EA2W group were up-regulated considerably (P0.05). In comparison with the OVX+CCI group, the AChE activities in PVN, ARC, and SON regions and the expressions of hypothalamic ChAT mRNA and VAChT in ARC region of OVX+CCI+EA2W group were up-regulated remarkably (P0.05). The effects in rats of CCI+EA2W group were evidently superior to those of OVX+CCI+EA2d group in up-regulating AChE activities in PVN, ARC, and SON regions, VAChT immunoactivity in ARC region, and expression levels of hypothalamic ChAT mRNA and M1R mRNA (P0.05). Similar situations were found in OVX+CCI rats after EA2W. It suggested a cumulative effect after repeated EA of ST36-GB34. Comparison between CCI+EA2W and OVX+CCI+EA2W groups showed that the effects in rats of the former group were evidently better than those of the latter group in up-regulating AChE activity in ARC and SON regions and the expressions of hypothalamic ChAT mRNA and M1 mRNA (P0.05), suggesting a reduction of EA2W effects after OVX.Repeated EA can significantly up-regulate AChE and VAChT activities and ChAT mRNA and M1R mRNA expressions in the hypothalamus of CCI and OVX+CCI rats, which may contribute to the cumulative analgesic effects of repeated EA and be closely related to the animals' neuromemory ability.

To study the effects of acupuncture analgesia on the hippocampus, we observed the effects of electroacupuncture (EA) and mitogen-activated protein kinase (MEK) inhibitor on pain-excited neurons (PENs) and pain-inhibited neurons (PINs) in the hippocampal area CA1 of sham or chronic constrictive injury (CCI) rats. The animals were randomly divided into a control, a CCI, and a U0126 (MEK1/2 inhibitor) group. In all experiments, we briefly (10-second duration) stimulated the sciatic nerve electrically and recorded the firing rates of PENs and PINs. The results showed that in both sham and CCI rats brief sciatic nerve stimulation significantly increased the electrical activity of PENs and markedly decreased the electrical activity of PINs. These effects were significantly greater in CCI rats compared to sham rats. EA treatment reduced the effects of the noxious stimulus on PENs and PINs in both sham and CCI rats. The effects of EA treatment could be inhibited by U0126 in sham-operated rats. The results suggest that EA reduces effects of acute sciatic nerve stimulation on PENs and PINs in the CA1 region of the hippocampus of both sham and CCI rats and that the ERK (extracellular regulated kinase) signaling pathway is involved in the modulation of EA analgesia.

Chronic pain is a common disability influencing quality of life. Results of previous studies showed that acupuncture has a cumulative analgesic effect, but the relationship with spinal cytokines neurotrophic factors released by astrocytes remains unknown. The present study was designed to observe the effect of electroacupuncture (EA) treatment on spinal cytokines neurotrophic factors in chronic neuropathic pain rats. The chronic neuropathic pain was established by chronic constrictive injury (CCI). EA treatment was applied at Zusanli (ST36) and Yanglingquan (GB34) (both bilateral) once a day, for 30 min. IL-1βmRNA, TNF-αmRNA, and IL-1 mRNA were detected by quantitative real-time PCR, and the proteins of BDNF, NGF, and NT3/4 were detected by Western blot. The expression levels of cytokines such as IL-1βmRNA, TNF-αmRNA, IL-6 mRNA, and neurotrophic factors such as BDNF, NGF, and NT3/4 in the spinal cord were increased significantly after CCI. The astrocytes released more IL-1βand BDNF after CCI. Repeated EA treatment could suppress the elevated expression of IL-1βmRNA, TNFαmRNA, and BDNF, NGF, and NT3/4 but had no effect on IL-6 mRNA. It is suggested that cytokines and neurotrophic factors which may be closely associated with astrocytes participated in the process of EA relieving chronic pain.

Results of our past studies showed that hippocampal muscarinic acetylcholine receptor (mAChR)-1 mRNA and differentially expressed proteins participating in MAPK signaling were involved in electroacupuncture (EA) induced cumulative analgesia in neuropathic pain rats, but the underlying intracellular mechanism remains unknown. The present study was designed to observe the effect of EA stimulation (EAS) on hippocampal extracellular signal-regulated kinases (ERK) and p38 MAPK signaling in rats with chronic constrictive injury (CCI) of the sciatic nerve, so as to reveal its related intracellular targets in pain relief. After CCI, the thermal pain thresholds of the affected hind were significantly decreased compared with the control group (P<0.05). Following one and two weeks’ EAS of ST 36-GB34, the pain thresholds were significantly upregulated (P<0.05), and the effect of EA2W was remarkably superior to that of EA2D and EA1W (P<0.05). Correspondingly, CCI-induced decreased expression levels of Ras, c-Raf, ERK1 and p-ERK1/2 proteins, and p38 MAPK mRNA and p-p38MAPK protein in the hippocampus tissues were reversed by EA2W (P<0.05). The above mentioned results indicated that EA2W induced cumulative analgesic effect may be closely associated with its function in removing neuropathic pain induced suppression of intracellular ERK and p38MAPK signaling in the hippocampus.

To observe the effect of electroacupuncture .(EA) stimulation of "Zusanli" (ST 36)-"Yang- lingquan" (GB 34) on expression of pain sensory and affection processing-related corticotropin-releasing factor (CRF) receptor, glutamatergic NMDA receptor and GABA receptor subtype genes in the amygdala in chronic constrictive injury (CCI) of the sciatic nerve rats, so as to reveal its mechanism underlying pain relief.Experiments were separately performed in 36 male Wistar rats which were randomized into normal control, CCI model and EA + CCI; normal control, CCI + negative affection (NA) model and CCl+ NA+ EA groups (n =6 in each group). Neuropathic pain model was established by ligature of the left sciatic nerve, and NA model established by ligation of the left sciatic nerve and repeated skin stimulation (acupuncture needle pricking + direct current stimulation) of the paw-bottom, once daily for 3 days. EA (2 Hz/15 Hz, 1 mA) was applied to bilateral ST 36-GB 34 for 30 min, once daily for 7 days. Thermal pain threshold (paw withdrawal latency, PWL) of the bilateral paws was measured by using a Tail-Flick Unit 37360. Expression levels of CRF-1 R, CRF-2 R, NR 2 A,NR 2 B,GABAaR and GABAcR genes in the amygdala were determined using quantitative RT-PCR.In comparison with the normal control groups, PWL difference (PWLD) values of the bilateral paws of CCIl model and CCI+NA model groups were significantly increased (P0. 05). In comparison with the model group, following 7 days' EA stimulation, PWLD were considerably decreased (P0. 05), showing a pain relief. RT-PCR results indicated that compared to the normal control group, the expression levels of CRF-1 R, CRF-2 R, NR 2 A and NR 2 B genes were apparently increased in the CCI model group (P0. 01, P0. 001), and those of CRF-1 R, CRF-2 R, NR 2 A, NR 2 B, GABAaR and GABAcR genes were remarkably down-regulated in the CCI + NA model group (P0. 05, P0. 01, P0. 001). After EA intervention for 7 days, CRF-2 R, NR 2 A and NR 2 B were significantly down-regulated in the CCI + EA group, and CRF-1 R, CRF-2 R, NR 2 B,GABAaR and GABAcR genes were obviously up-regulated in the CCI + NA + EA group (P0. 01, P0. 001).Repeated EA stimulation of ST 36-GB 34 has a definite analgesic effect in neuropathic pain and negative affection rats, which may be respectively related to its effects in down-regulating expression of CRF-2 R, NR 2 A and NR 2 B genes, and up-regulating expression of CRF-1 R, CRF-2 R, NR 2 B,GABAaR and GABAcR genes in the amyg- dala.

Background Cumulating evidence has revealed the effectiveness of acupuncture therapy in relieving pain via immunoregulation. However, its underlying mechanism remains unknown. The present study was designed to determine the changes of immunogenic responses at different time-points of electroacupuncture (EA) interventions in neuropathic pain rats. Methods The neuropathic pain model was established by ligature of the left sciatic nerve to induce chronic constriction injury (CCI). EA was applied at Zusanli (ST36) and Yanglingquan (GB34) for the EA groups. The thermal pain threshold was detected with an algesia-detector. The subgroups of plasma and splenic lymphocytes were determined via fluorescence-activated cell sorting. Specific inflammatory cytokines were assayed using an ELISA-based bead multiplex assay. The activities of splenic natural killer (NK) cells and cytotoxic T lymphocytes were detected by methyl thiazolyl tetrazolium colorimetric method. For confirming the involvement of NK cell in EA-analgesia, anti-asialo-ganglio-N-tetraosylceramide (anti-asialo-GM1) antibody was given to CCI rats before EA. Results Following CCI, the thermal pain threshold of the affected hind footpad was significantly decreased, and increased from the 3rd day to the 12th day after EA interventions, presenting a time-dependent tendency from the 5th day on. From day 3 to 5 of EA interventions, the percentages and activity of splenic NK cells, concentrations of splenic interleukin-2 (IL-2) and beta-endorphin (β-EP) were significantly increased. Meanwhile, the concentrations of plasma IL-2, IL-1β and gamma-interferon (IFN-γ) were significantly decreased and returned to the normal level on day 12 following EA. Plasma transforming growth factor-β (TGF-β) levels were considerably upregulated on day 5 and 12 following EA. The CD4+/CD8+ T cell ratio was markedly downregulated compared with the control and CCI groups on day 5 and returned to the normal level on day 12 following EA. After depleting NK cells by anti-asialo-GM1 antibody, the increased thermal pain threshold following EA intervention was obviously reduced. Conclusions Repeated EA interventions have a time-dependent cumulative analgesic effect in neuropathic pain rats, which is closely associated with its regulatory effects on NK cells, splenic IL-2, β-EP, and plasma IL-2, IL-1β, IFN-γ and TGF-β levels.

To observe the effect of electroacupuncture (EA) at "Zusanli"(ST 36)-"Yanglingquan"(GB 34) on pain behavior and expression of hippocampal neuronal nitric oxide synthase (nNOS), inducible nitric oxide synthase(iNOS)and cGMP-dependent protein kinase (PKG) mRNA in rats with chronic neuropathic pain so as to analyze its mechanism underlying analgesia.Forty male Wistar rats were randomly divided into control, CCI model, EA-2 Hz, EA-2 Hz/15 Hz, EA-100 Hz groups, with 8 cases in each group. Chronic neuropathic pain model was established by ligature of the left sciatic nerve under anesthesia (Urethane + Alpha-Chloralose) except rats in the control group. EA(2 Hz, 2 Hz/15 Hz, 100 Hz, 1 mA) was applied to bilateral "Zusanli"(ST 36)-"Yanglingquan"(GB 34) for 30 min, once each day for 2 weeks. The thermal and mechanical paw withdrawal latencies (pain thresholds) of the bilateral limbs were detected before and after EA interventions. The hippocampal tissue of the rat was collected for detecting the expression levels of nNOS, INOS and PKG genes using quantitative real-time-PCR technique.In comparison with the control group, the thermal and mechanical pain thresholds of the model group were decreased obviously (P0. 05).Compared with the model group, both thermal and mechanical pain thresholds of the EA-2 Hz, EA-2 Hz/15 Hz and EA-100 Hz groups were markedly increased after EA intervention for 3, 7, 10 and 14 days (P0. 05). Compared with the control group, the expression levels of hippocampal nNOS and PKG mRNA were significantly and moderately up-regulated in the model group (P0. 05). While in comparison with the model group, the expression levels of hippocampal nNOS and PKG mRNA in the EA-2 Hz, EA-2 Hz/15 Hz and EA-100 Hz groups were markedly down-regulated (P0. 05). No significant differences were found among the EA-2 Hz, EA-2 Hz/15 Hz and EA-100 Hz groups in the analgesic effect and in down-regulating hippocampal nNOS and PKG mRNA expression (P0.05). However, the recovery state of the pain reaction of both EA-2 Hz and EA-2 Hz/ 15 Hz groups was relatively better than that of the EA-100 Hz group from day 3 to 10 after EA intervention.EA stimulation of "Zusanli"(ST 36)-"Yanglingquan"(GB 34) at 2 Hz, 2 Hz/15 Hz and 100 Hz can significantly suppress chronic neuropathic pain induced in CCI rats, which may be closely associated with its effects in down-regulating hippocampal nNOS and PKG mRNA expression levels.

The present study was aimed to determine if cervicospinal substance P (SP) and its neurokinin-1 receptor (NK-1R), calcitonin gene-related peptide (CGRP), cyclooxygenase-1 (COX-1), and prostaglandin E2 (PGE2) were involved in electroacupuncture (EA) analgesia in neck-incision pain rats. EA intervention was applied to bilateral Futu (LI18), Hegu (LI4)-Neiguan (PC6), and Zusanli (ST36)-Yanglingquan (GB34) for 30 min. Cervicospinal SP and CGRP immunoactivity was detected by immunofluorescence technique, NK-1R and COX-1 protein and mRNA expression levels were determined using Western blot and real-time PCR, respectively, and PGE2 content was measured using ELISA. Outcomes indicated that EA of EA-LI18 and LI4-PC6 (not ST36-GB34) significantly suppressed neck-incision induced decrease of thermal pain threshold (P<0.05). EA stimulation of LI18 and LI4-PC6 markedly inhibited neck-incision induced upregulation of SP and CGRP immunoactivity, NK-1 R and COX-1 mRNA and protein expression levels, as well as the increase of PGE2 content in the dorsal cervicospinal cord (P<0.05). These findings showed that LI18 and LI4-PC6 EA stimulation-induced downregulation of SP, CGRP, NK-1R, COX-1, and PGE2 levels in the dorsal cervicospinal cord may contribute to their effects in relieving neck-incision pain. This study highlights the targets of EA intervention for reducing post-thyroid-surgery pain for the first time.

Background Evidence is building steadily on the effectiveness of acupuncture therapy in pain relief and repeated acupuncture-induced pain relief is accompanied by improvement of hippocampal neural synaptic plasticity. To further test the cellular and molecular changes underlying analgesic effect of acupuncture, the global change of acupuncture associated protein profiles in the hippocampus under neuropathic pain condition was profiled. Methods The chronic constrictive injury (CCI) model was established by ligature of the unilateral sciatic nerve in adult Wistar rats. Rats were randomized into normal control (NC) group, CCI group, and CCI with electroacupuncture (EA) stimulation group. EA was applied to bilateral Zusanli (ST36) and Yanglingquan (GB34) in the EA group. Differentially expressed proteins in the hippocampus in the three groups were identified by two-dimensional gel electrophoresis and matrix-assisted laser desorption/ionization time of flight mass spectrometry. The functional clustering of the identified proteins was analyzed by Mascot software. Results After CCI, the thermal pain threshold of the affected hind footpad was decreased and was reversed gradually by 12 sessions of acupuncture treatment. Following EA, there were 19 hippocampal proteins identified with significant changes in expression (>2-fold), which are involved in metabolic, physiological, and cellular processes. The top three canonical pathways identified were “cysteine metabolism”, “valine, leucine, and isoleucine degradation” and “mitogen-activated protein kinase (MAPK) signaling”. Conclusions These data suggest that the analgesic effect of EA is mediated by regulation of hippocampal proteins related to amino acid metabolism and activation of the MAPK signaling pathway.

To observe the effect of electroacupuncture (EA) at "Futu" (LI 18),etc. on the pain threshold and expression of metabotropic glutamate receptor subtype 5 (mGluR 5), cyclic adenosine monophosphate (cAMP), mitogen-activated protein kinase (MAPK), cAMP responsive element binding protein (CREB) genes in the cervico-spinal dorsal region in rats with neck incision pain so as to analyze its underlying analgesic mechanism in performing thyroid surgery.Forty male Wistar rats were randomly divided into control, model, Futu (LI 18), Hegu (LI 4)-Neiguan (PC 6), Zusanli (ST 36)-Yanglingquan (GB 34) groups, with 8 cases in each group. Neck-incision pain model was established by making a longitudinal incision along the midline of the neck under anesthesia (isoflurane) except rats in the control group. EA(2 Hz/15 Hz, 1-2 mA) was applied to bilateral LI 18, LI 4-PC 6 and ST 36-GB 34 for 30 min, 4 h, 24 h and 48 h after modeling, respectively. The thermal pain threshold was detected before modeling, and before and after each treatment. After removing the ventral part, the spinal tissue of the cervical 1 -4 segments was collected for detecting the expression of mGluR 5, cAMP, MAPK, CREB genes by using quantitative real-time-PCR technique.In comparison with the control group, the pain threshold of the model group was decreased obviously (P0.05). Compared with the model group, the pain thresholds of the LI 18 and LI 4-PC 6 groups were upregulated markedly after treatment (P0.05). No significant differences were found between the LI 18 and LI 4-PC 6 groups, and between the model and ST 36-GB 34 groups in pain thresholds (P0.05). Compared with the control group, the expression le-vels of mGluR 5 mRNA, cAMP mRNA and CREB mRNA in the cervico-spinal cord were upregulated significantly in the model group (P0.05). While in comparison with the model group, cervico-spinal cAMP mRNA, and CREB mRNA were down-regulated markedly (P0.05) and mGluR 5 mRNA was down-regulated moderately (P0.05) in the LI 18 group, rather than in the LI 4-PC 6 and ST 36-GB 34 groups (P0.05).EA-LI 18 can significantly suppress neck incision pain induced pain reaction, which may be closely associated with its functions in down-regulating expression levels of intracellular cAMP mRNA and CREB mRNA in the cervico-spinal cord.

To observe the effect of electroacupuncture (EA) at different acupoints on the expression of gamma aminobutyric (GABA) receptor (R) subunit genes in the cervical spinal cord in rats with thyroid regional inflammatory pain so as to analyze its analgesic mechanism for thyroid surgery.A total of 50 Wistar rats were randomized into control, model, Futu (LI 18), Hegu (LI 4)-Neiguan (PC 6, LI 4-PC 6), Zusanli (ST 36)-Yanglingquan (GB 34, ST 36-GB 34) groups, with 10 rats in each group. Thyroid regional pain model was established by subcutaneous injection of 2.5% formalin (100 microL). Ten minutes after modeling, EA (2 Hz/15 Hz, 1 mA) was applied to LI 18, LI 4-PC 6 and ST 36-GB 34 for 30 min, respectively. The animals' face-grooming (FG) times in 5 min and thermal pain threshold (paw withdrawal latency, PWL) were recorded. The expression of GABA(A) R, GABA(B) R1, and GABA(B) R2 genes in the cervical 1-3 segments of the spinal cord 80 min after modeling was detected by using reversed transcription-polymerase chain reaction (RT-PCR). Histological changes of the tissues of the thyroid region were observed by using H. E. staining.After subcutaneous injection of formalin, the animals' FG times in 5 min were increased considerably and the thermal pain threshold was decreased obviously in the model group (P0.05). Concomitantly, the expression levels of GABA(B) R1, and GABA(B) R2 genes of the cervical spinal cord were upregulated significantly in the model group (P0.05), and GABA(A) R expression was increased slightly (P0.05). Compared with the model group, the FG times in 5 min in the LI 18 and LI 4-PC 6 groups at 40 min and 70 min after modeling were decreased significantly (P0.05), and their thermal pain threshold values were increased markedly (P0.05). The expression levels of GABA(B) R1 mRNA, GABA(B) R2 mRNA and GABAA R mRNA were significantly higher in the LI 18 and LI 4-PC 6 groups than in the model group (P0.05). The expression level of GABA(B) R1 mRNA of the ST 36-GB 34 group was obviously higher than that of the model group (P0.05). The inflammatory cells in the formalin-injected thyroid region were relatively fewer in the LI 18 and LI 4-PC 6 groups than in the model group.Both EA of LI 18 and LI 4-PC 6 can significantly suppress formalin-injection induced pain reactions in the thyroid region, which may be closely associated with its effects in upregulating expression levels of cervico-spinal GABA(B) R1 mRNA, GABA(B) R2 mRNA and GABA(A) R mRNA, and reduce regional inflammatory reactions in the thyroid region.

To observe the effect of electroacupuncture(EA) of bilateral "Futu" (LI 18) on the immunoactivity of substance P (SP), NK-1 receptor (R), cyclooxygenase-1 (COX-1), 5-HT 1 AR and 5-HT2 AR in the cervical spinal dorsal horn of rats with neck incision pain, so as to explore its underlying mechanism in relieving incision pain.A total of 40 Wistar rats were randomly divided into control, model (incision pain), EA-Futu(LI 18), and EA-Zusanli(ST 36)-Yanglingquan (GB 34, EA-ST 36-GB 34) groups (n = 10/group). A 1.5 cm longitudinal incision was made along the middle of the neck in pentobarbital-anesthetized rats. Pain threshold (PT) was measured using radiant heat. EA (1-2 mA, 2 Hz/15 Hz) was applied to bilateral LI 18, ST 36-GB 34 for 30 min. The expression of SP, NK-1 R, COX-1, 5-HT 1 AR and 5-HT2 AR in the spinal cord (C1-C4) tissue were detected with immunohistochemistry.After the operation, the thermal PT was decreased obviously in markedly after treatment (P0.05), and no significant changes were found in PT in EA-ST 36-GB 34 group (P0.05). The immunoactivity of SP, NK-1 R, COX-1 in the superficial dorsal horn in model group was increased significantly and that of 5-HT 1 AR and 5-HT 2 AR significantly and mildly, separately compared with control group (P0.05). In comparison with model group, the immunoreactivity of SP, NK-1 R and COX-1 was decreased considerably, and that of 5-HT 1 AR and 5-HT 2 AR was upregulated remarkably in EA-LI 18 group (P0.05). No significant changes were found in the immunoactivity of SP, NK-1 R, COX-1, 5-HT 1 AR and 5-HT 2 AR in EA-ST 36-GB 34 group (P0.05).EA-Futu (LI 18) can significantly suppress pain reaction of neck incision in the rat, which is closely associated with its effects in downregulating the expression of SP, NK-1 R, COX-1 and upregulating that of 5-HT 1 AR and 5-HT 2 AR in the spinal dorsal horn.

To observe the effect of electroacupuncture (EA) of different acupoint groups on the expression of NR 2 B subunit of N-methyl-D-aspartate (NMDA) receptor in the cervical spinal cord in rats with thyroid regional pain so as to analyze the analgesic mechanism of acupuncture for performing thyroid surgery.A total of 50 Wistar rats were randomized into control, model, EA-Futu (ST 32), EA-Hegu (LI 4)-Neiguan (PC 6, EA-LI 4-PC 6), EA-Zusanli (ST 36)-Yanglingquan (GB 34, EA-ST 36-GB 34) groups, with 10 cases in each. Thyroid regional pain model was established by subcutaneous injection of 2.5% formaldehyde. Ten minutes after modeling, EA (2 Hz/100 Hz, 1 mA) was applied to ST 32, LI 4-PC 6 and ST 36-GB 34 for 30 min respectively. The animals' face-grooming (FG) times and paw withdrawal latency (PWL) of radiant heat irradiation were recorded. The spinal cord tissues of the cervical 1-3 segments were removed for detecting the expression of NR 2 B mRNA and protein of NMDA receptor with reversed transcription-polymerase chain reaction and Western blotting techniques separately.After subcutaneous injection of 2.5% formaldehyde, the animals' FG times increased considerably and the PWL was shortened obviously (P0.05). Compared with model group, the FG times of EA-ST 32 and EA-LI 4-PC 6 groups at 40-45 min and 70-75 min after modeling decreased significantly, and their PWL prolonged markedly (P0.05). The effect of EA-ST 32 was apparently superior to that of EA-LI 4-PC 6 group in reducing FG times. No significant differences were found between EA-ST 32 and EA-LI 4-PC 6 groups in PWL, and between model and EA-ST 36-GB 34 groups (P0.05). Results of NR 2 B mRNA and protein detections showed no significant differences among the 5 groups in their expression (P0.05). Comparison of the phosphorylated NR 2 B among 5 groups showed that EA-ST 32 and EA-LI 4-PC 6 could effectively down-regulate 2.5% formaldehyde induced increase of NR 2 B phosphorylation levels (P0.05), while EA-ST 36-GB 34 had no obvious effect on it (P0.05).Both EA-ST 32 and EA-LI 4-PC 6 can significantly suppress thyroid regional pain induced behavior reactions, which may be closely associated with their effects in down-regulating NR 2 B phosphorylated level. The analgesic effect of EA-ST 32 and EA-LI 4-PC 6 for thyroid surgery is relatively more effective in comparison with EA-ST 36-GB 34.

To explore the mechanism of electroacupuncture (EA)-induced cumulative analgesic effects on chronic pain in rats with or without ovariectomy (OVX).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 beta-endorphin (EP) and adrenocorticotrophic hormone (ACTH) contents were detected by immunoradioassay.Compared with the CCI group, PWLD of the CCI+EA-3 W group decreased significantly (P0.05). Compared with the OVX+CCI group, PWLD of the OVX+CCI+EA-3 W group was lowered considerably (P0.05), but the value was markedly higher than its basal value and those of the normal control and CCI+EA groups (P0.05). 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 (P0.05), while the number of target platform crossings was decreased significantly (P0.05), suggesting an impairment of the OVX rats' learning-memory ability. In simple CCI rats, both beta-EP and ACTH contents of the pituitary increased markedly (P0.05), and those of the hypothalamus decreased obviously compared to the normal control group (P0.05). After EA, pituitary and hypothalamic ACTH levels were significantly lowered at 2 d and hypothalamic ACTH and beta-EP contents increased obviously at 3 W in comparison with the CCI group (P0.05). In OVX+CCI rats, following EA, pituitary beta-EP contents at 2 d, 2 W and 3 W, and hypothalamic beta-EP and ACTH contents at 2 W and hypothalamic ACTH levels at 3 W increased significantly (P0.05), but hypothalamic beta-EP level at 3W decreased markedly (P0.05). The effects of repeated EA in lowering pituitary ACTH and raising hypothalamic beta-EP and ACTH levels disappeared after OVX+CCI.Repeated EA has a cumulative analgesic effect, which is closely associated with its effects in regulating pituitary and hypothalamic beta-EP and ACTH levels. OVX may weaken the analgesic effect of EA by affecting hypothalamic-pituitary axis activity.

To observe the effect of electroacupuncture (EA) of different acupoint groups on mean arterial pressure (MAP) and heart rate variability (HRV) in hypotension rats.A total of 70 Wistar female rats were randomized into model, "Neiguan" (PC 6)-"Daling" (PC 7), "Waiguan" (SJ 4)-"Yangchi" (SJ 5), "Tianshu" (ST 25)-"Wailing" (ST 26), "Dachangshu" (BL 25)-"Qihaishu" (BL 24), "Baihui" (GV 20)-"Qianshencong" (EX-HN), and"Guangming" (GB 37)-"Xuanzhong" (GB 39) groups, with 10 cases in each. Hypotension model was established by bleeding (2.5-3 ml) through carotid artery. Immediately after bleeding, EA (2/15 Hz, 1 mA, 30 min) was applied to the above-mentioned acupoints of the 6 EA groups. MAP and ECG were recorded, then HRV was analyzed by using software Chart 5.2.1.MAP declined significantly after bleeding. Compared with model group, MAP values of PC6-PC7 and GB37-GB39 groups increased significantly 15 min and 30 min after bleeding, and those of ST25-ST26 and GV20-EX-HN groups also increased apparently 30 min after bleeding (P0.05). No marked effects were observed in EA of SJ4-SJ5 and BL25-BL24 groups (P0.05). The effect of PC6-PC7 and GB37-GB39 groups was significantly superior to that of SJ4-SJ5, BL25-BL24 and GV20-EX-HN groups in elevating MAP 30 min after bleeding (P0.05). Compared with model group, heart rate (HR) of PC6-PC7 group was increased significantly 15 min and 30 min after bleeding (P0.05). After bleeding, low frequency (LF), LF/high frequency (HF) and very low frequency (VLF) increased apparently. Compared with model group, LF, LF/HF and VLF of PC6-PC7 and GB37-GB39 groups decreased significantly 30 min after bleeding (P0.05), suggesting a better balancing effect of EA of PC6-PC7 and GB37-GB39 on the activities of sympathetic and vagus nerves.EA of different acupoint groups has its own relative specificity in regulating MAP and HR in the rat, and PC6-PC7 EA and GB37-GB39 EA have a better efficacy, which is closely associated with their effects in balancing activities of the autonomic nerve system.

To observe the effect of electroacupuncture (EA) of "Neiguan" (PC6) and "Gongsun" (SP4) on pathological changes of the heart and stomach in rats with acute myocardial ischemia (AMI), and to explore its underlying mechanism.Fifty Wistar rats were randomized into control, model, PC6, SP4 and PC6 + SP4 groups (n = 8 each group). An AMI model was established by occlusion of the descending anterior branch (DAB) of the left coronary artery. ECG-ST of cervico-thoracic lead and electrogastrogram (EGG) were recorded. EA was applied to PC6, SP4 and PC6 + SP4 groups, respectively. At the end of experiments, the rats were transcardically perfused with 4% paraformaldehyde, and the heart base myocardium, gastric antrum and duodenum tissues were sampled, sectioned and stained with a reduced form of nicotinamide-adenine dinucleotide phosphate (NADPH)-diaphorase histochemical method for displaying nitric oxide synthase (NOS) activity.After AMI, ECG-ST values elevated. After EA, the elevated ECG-ST values at 20 min in PC6 group, at 30 min in PC6 + SP4 and SP4 groups had no significant differences in comparison with their respective basal values before AMI. Following AMI, the amplitude and frequency of slow waves of EGG decreased remarkably (P0.05). At 30 min after EA, the mean amplitude and frequency of slow waves of EGG in the three EA groups had no marked differences compared with their individual basal levels and those in the control group. After AMI, the mean integral grey values of NOS-positive product in myocardium, gastric antrum and duodenum tissues in the model group increased remarkably in comparison with the control group, while those in three EA groups were lower than those in the model group. No significant differences were found in ECG-ST and EGG improvement among the three EA groups. However, EA of PC6 had a better effect on ECG-ST and EA of PC4 had a better effect on EGG, respectively.EA of PC6, SP4 and PC6 + SP4 can significantly promote the recovery of cardiac and gastric electrical activities after AMI, and up-regulate NOS expression in myocardium, gastric antrum and duodenum tissues.

To observe the effect of electroacupuncture (EA) of different acupoints on abnormal electrohysterogram (EHG) in pregnant rats, so as to analyze their regularities in regulating dysfunction of the viscera.A total of 48 Wistar pregnant rats (18-20 days) anesthetized with mixture solution of 1.5% chloralose and 25% urethane (i. p) were randomized into control (n=10), "Sanyinjiao" (SP 6, n=9), "Hegu" (LI 4, n=8), "Neiguan" (PC 6, n=0), and "SP 6 + LI 4" (n=11) groups. EHG was recorded by using a bipolar stainless steel electrode inserted in the sub-perimetrium layer of the left mid part of the uterus. The reference electrode was placed beneath the skin of the incision. Oxytocin and gesterol were given to the local uterus nearby the recording electrode to induce abnormal excitement and suppression of EHG respectively. EA (1-2 mA, 2/15 Hz) was applied to the above-mentioned acupoints separately for 20 min in the EA groups and the influences of EA on the amplitude and frequency of burst (fast) waves and slow waves of EHG were analyzed.Compared with the control group, EA of SP 6 + LI 4 and SP 6 groups had apparent inhibitory effects on oxytocin-induced increases of the frequency and amplitude of both fast and slow waves (P0.05); and EA of LI 4 also had a markedly inhibitory effect on the amplitude of fast waves (P0.05). No marked effects on both frequency and amplitude of fast waves and slow waves of EHG were found in the PC 6 group (P0.05). In comparison with the control group, EA of SP 6+LI 4 and SP 6 could relieve or significantly relieve progesterone-induced suppression of the frequency and amplitude of both fast and slow waves (P0.05); and the effects of SP 6 + LI 4 appeared earlier and lasted longer than those of SP 6; while EA of LI 4 and PC 6 had no obvious effect on progesterone-induced changes of the frequency and amplitude of both fast and slow waves (P0.05).EA different acupoints have their own relative specificity in regulating abnormal EHG.

To observe the accumulative analgesic effect of electroacupuncture (EA) and the simultaneous changes of protein kinase A (PKA) expression in hypothalamus and hippocampus in rats with chronic constrictive injury (CCI) or/and learning-memory impairment.Sixty-eight female Wistar rats were randomized into normal control, CCI, CCI + EA 2 d, CCI + EA 2 w, OVX + CCI, OVX + CCI + EA 2 d and OVX + CCI + EA 2 w groups, with 10 cases in each except OVX + CCI group (n=8). CCI pain model was established by ligature of the right sciatic nerve with surgical suture. EA (2/15 Hz, 1-2 mA, 30 min) was daily applied to bilateral "Zusanli" (ST 36) and "Yanglingquan" (GB 34) for 2 days (2 d) and 2 weeks (2 w) respectively. Neuro-memory impairment was induced by OVX plus subcutaneous injection of D-galactose. Hyperalgesic scores (HS) were detected with radiation-heat irradiation and PKA activity was detected by immunohistochemical method.After CCI, HS of all groups increased significantly in comparison with normal control group (P0.05). In simple CCI rats, compared with CCI group, HS of both CCI + EA 2 d and CCI + EA 2 w groups decreased markedly (P0.05), and that of CCI + EA 2 w group was evidently lower than that of CCI + EA 2 d group on the 18th day after CCI (P0.05). In memory impairment rats, HS of both OVX + CCI + EA 2 d and OVX + CCI + EA 2 w groups was significantly lower than that of OVX+ CCI group (P0.05); and no significant difference was found between OVX + CCI + EA 2 w and OVX + CCI + EA 2 d groups in HS (P0.05). Results of immunohistochemistry showed that the integral grey values (IGV) of PKA of paraventricular nucleus (PVN), arcuate nucleus (ARC) and supraoptic nucleus (SON) of hypothalamus in CCI + EA 2 w group were significantly lower than those in normal control and CCI + EA 2 d groups (P0.05). IGV of PVN and SON in OVX + CCI + EA 2 w group were also markedly lower than those in OVX + CCI group (P0.05), displaying upregulation and cumulative increase of PKA expression by EA 2 w. IGV of PKA, ARC and SON in OVX + CCI + EA 2 w group were markedly higher than those in CCI + EA 2 w group (P0.05), suggesting an apparent attenuation of the cumulative upregulation effect of PKA expression after learning-memory injury. The changing tendency of PKA expression in hippocampal CA1 region was similar to that of SON after repeated EA of ST36 and GB34.Repeated EA has a cumulative analgesic effect in CCI rats, which is probably related to its resultant upregulation of PKA expression in neurons of hypothalamus and hippocampus and the animals' neuro-memory.

To observe the regularity of electroacupuncture (EA) analgesia and to analyze its relation to hypothalamus-pituitary-adrenal cortex axis function in chronic constrictive injury (CCI) and ovariectomy (OVX) rats.A total of 110 Wistar rats anesthetized with mixture solution of 1.5% chloralose (50 mg/kg) and 25% urethrane (420 mg/kg, i.p.) were randomized into control (n=10), CCI (n =10), CCI + EA (n=30), OVX + CCI (n=30), OVX + CCI + EA (n=30) groups, and the later 3 groups were further divided into 2 times (2 t), 2 weeks (2 w) and 3 w time courses, with 10 cases in each. Forty-five days after OVX, Morris water maze test was conducted to evaluate the OVX rats' memory-learning ability. Chronic pain model was established by ligating the right sciatic nerve with a piece of suture. EA (2/15 Hz, 1 mA) was applied to bilateral "Zusanli" (ST 36)-"Yanglingquan" (GB 34) for 30 min, once daily for 2 t, 2 w, 3 w respectively. The paw withdrawal latency (PWL) was detected to be used as the pain threshold. Under deep anesthesia, the rat was decapitated for collecting blood samples. Plasma adrenocorticotropic hormone (ACTH), beta-endorphine (EP), cortisone (COR) contents were detected using radioimmunoassay.In comparison with control group, PWL difference values (PWLDV) of CCI + EA, OVX + CCI and OVX + CCI + EA groups increased significantly (P0.05), suggesting a marked decrease of pain threshold. Compared with CCI group, PWLDV of CCI + EA group at 3 w decreased significantly (P0.05), being close to normal control group (P0.05). Compared with OVX + CCI group, PWLDV of OVX + CCI + EA at 2 w and 3 w lowered significantly (P0.05), suggesting an evident pain relief. In comparison with CCI + EA group, PWLDV of OVX + CCI + EA group at most time courses were considerably higher (P0.05), showing a better cumulative analgesic effect in CCI rats without OVX. In CCI group, plasma beta-EP increased slightly, ACTH had no clear changes, and COR lowered lightly at 2 t. No significant differences were found between control and CCI + EA groups in beta-EP and ACTH levels at 2 w and 3 w (P0.05), only COR levels of CCI + EA group at 2 w and 3 w increased significantly (P0.05). Compared with control group, beta-EP levels of OVX + CCI group at 2 w and 3 w increased significantly (P0.05); plasma ACTH had no marked changes (P0.05); COR contents of OVX + CCI group decreased evidently at 2 t and increased markedly at 2 w (P0.05). Compared with OVX + CCI group, in OVX + CCI + EA group, beta-EP levels of 2 t and 2 w decreased significantly (P0.05); ACTH levels increased evidently at 2 t and 3 w, and decreased markedly at 2 w (P0.05); and COR level at 2 w decreased significantly (P0.05). It indicated that when cumulative EA analgesia appeared, in CCI animals, only plasma COR level increased pronouncedly, while in OVX + CCI rats, both plasma beta-EP and COR contents decreased evidently.Both plasma beta-EP and COR are involved in the accumulative analgesic effect of EA in the rat, and decline of learning memory ability may weaken the analgesic effect of EA to a certain degree, but no clear correlation tendency is found between changes of plasma beta-EP and COR and the improvement of pain behavior.

To observe the effect of electroacupuncture (EA) of different acupoints on electrical activities of the uterus in rats.A total of 79 Wistar rats anesthetized with mixture solution of 1.5% chloralose (50 mg/kg) and 25% urethrane (420 mg/kg, i.p.). In the first part of this study, 40 non-pregnant rats were randomized into control, "Neiguan" (PC 6), "Hegu" (LI 4) and "Sanyinjiao" (SP 6) groups, with 10 cases in each group. In the second part of this study, 39 pregnant rats were evenly randomized into control, "Neiguan" (PC 6) and "Sanyinjiao" (SP 6) groups, with 13 cases in each group. Electrohysterogram was recorded by using a bipolar stainless steel electrode inserted in the sub-perimetrium layer of the mid part of the uterus. EA (2 mA, 5/15 Hz) was respectively applied to bilateral P, L4, and SP6 for 20 min.(1)In nonpregnant rats, compared with control group, the amplitude and frequency of fast waves (burst action potentials) and the amplitude of slow waves in SP6 increased significantly (P0.05), and EA of LI4 had a similar effect in increasing the frequency of fast waves; while following EA of PA6, both frequency and amplitude of fast waves nd the frequency of slow waves decreased significantly (P0.05). In comparison with PC6 group, most indexes of SP6 and LI4 groups during EA and 0-5 min after EA presented significant differences (P0.05, 0.001). (2) In pregnant rats, compared with control group, both the amplitude and frequency of fast waves and the amplitude of slow waves of the electrohysterogram in SP6 group increased significantly (P0.05) and lasted a longer time; while the frequency of both fast and slow waves decreased considerably in PC6 group (P0.05). Comparison between SP6 and PC6 groups showed significant differences in the frequency and amplitude of fast waves and the frequency of slow waves during EA and after EA (P0.05).EA of SP6 and LI4 can activate the myoelectrical activities of the uterine in both non-pregnant and pregnant rats, and the effect of EA of SP6 is stronger, whereas EA of PC6 can inhibit the myoelectrical activities of the uterine. Different acupoints have their relatively specific effect.

ObjectiveTo 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.MethodsFifty 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.ResultsCRD induced an increase in blood pressure that was significantly inhibited by EA at all points (all P

Background Cumulating evidence has shown a close correlation between electroacupuncture stimulation (EAS) frequency-specific analgesic effect and central opioid peptides. However, the actions of hippocampal acetylcholinergic receptors have not been determined. This study aims to observe the effect of different frequencies of EAS on the expression of hippocampal muscarinic and nicotinic acetylcholinergic receptors (mAChRs, nAChRs) in neuropathic pain rats for revealing their relationship. Methods Forty male Wistar rats were randomly and equally divided into sham, CCI model, 2, 2/15 and 100 HzEA groups. The neuropathic pain model was established by ligature of the left sciatic nerve to induce chronic constriction injury (CCI). EAS was applied to bilateral Zusanli (ST36) and Yanglingquan (GB34) for 30 min, once daily for 14 days except weekends. The mechanical pain thresholds (withdrawal latencies, PWLs) of bilateral hindpaws were measured. The expression levels of hippocampal M1 and M2 mAChR, and α4 and β2 nAChR genes and proteins were detected by quantitative RT-PCR and Western blot, separately. The involvement of mAChR and nAChR in the analgesic effect of EAS was confirmed by intra-hippocampal microinjection of M1mAChR antagonist (Pirenzepine) and α4β2 nAChR antagonist (dihydro-beta-erythroidine) respectively. Results Following EAS, the CCI-induced increase of difference values of bilateral PWLs on day 6 and 14 was significantly reduced (P 0.05). The analgesic effect of EAS was abolished by intra-hippocampal microinjection of M1mAChR and α4β2 nAChR antagonists respectively. Conclusions EAS of ST36-GB34 produces a cumulative analgesic effect in neuropathic pain rats, which is frequency-dependent and probably mediated by hippocampal M1 mAChR and β2 nAChR proteins.