Pain, as one of the most common clinical symptoms, seriously affects the quality of life of patients.Transient Re-ceptor Potential Vanilloid Type 1 (TRPV1) and Purinergic receptor(P2X3)are both involved in the transmission of a variety of patho-logical pain signals.Their interaction is less reported.This article reviews the interaction between TRPV1 and P2X3 in the pain signal transduction, and provides a new way for the treatment of pain.

Objective:The aim of this study was to observe the role of NO in the action of tetramethylpyrazine (TMP) on arterioles vasomotion induced by noradrenaline (NA), in order to make further understand of vasodilation mechanism of TMP.Methods: Albino rabbits weighting 2.0 ～ 2.5 kg were anesthetized. They were ventilated with room air via tracheotomy tube. The arterial pressure was monitored with a pressure transducer attached to a polyethylene canula in the right common carotid artery by four channel polygraph, the intestinal loop was mounted on the stage of an inverted microscope and bathed in balanced Kreb Ringer solution maintained at 37.5 ?C . The inside diameter of arterioles were measured manully on a TV monitor using a TV camera mounted on the microscope. Observe the changes of BP、 microcirculation and filtration of true capillary after injection of TMP 8mg/kg、 N G monomethyl L arginine( L NMMA) 10mg via a cannula in the left carotid artery after topical application of NA(0.8?g) conducted in the measured field. Results:TMP can inhibit spontaneous vasomotion in vasodilation; L NMMA can inhibit it in vasoconstriction stage. L NMMA have no effect on the action of TMP. Conclusions: Endogenous NO has no role in TMP's vasodilation.

Animals ; Bone Neoplasms ; Bone and Bones ; Humans ; Models, Animal ; Neoplasms ; Pain

Postoperative ileus (POI) is a common abdominal postoperative complication of surgery as well as obstetrics and gynecology. There is a lack of an effective method of modern medicine due to its complex pathophysiological mechanism and the postoperative physiological disorder of patient. Acupuncture has remarkable regulatory effects on gastrointestinal function. Some clinical studies indicated that acupuncture was an effective method to treat POI, which could reduce the duration of POI and the treatment costs of patients in hospital. However, the mechanism and law of acupuncture on treating POI is still unclear. Some clinical studies indicated that the regulatory effect of acupuncture on the gastrointestinal motility was associated with its regulation of the autonomic nerve system and immune system. Based on its effect on regulating autonomic nerve system and immune system, acupuncture would be a potential and safe treatment for POI.

Objective To observe the functional changes of T lymphocytes in the spleen of rats with bone cancer pain.Methods forty-one healthy female Sprague-Dawley rats were used in this study, and were divided into blank control, PBS and Walker-256 tumor groups.Bone cancer pain model was established by inoculation of Walker 256 cancer cells into the tibial cavity.The paw withdrawal threshold (PWT), paw withdrawal thermal latency (PWL), and spontaneous pain (SP) were all measured before modelling (as base) and at 4, 6, 8, 10, 12, 14, 16, 18, and 20 days after modelling. The function of T lymphocyte proliferation, and the content of T lymphocytes and their subgroups in the spleen were detected by cell counting kit-8 method and flow cytometry, respectively, on day 20 after modelling.Results Before modellng, there were no differences of PWT, PWL, and SP between the PBS and model groups.After modelling, the PWT and SP of model group were significantly decreased on day 4, and were always lower than that of PBS group during the experiment.Statistical analysis revealed that Walker-256 cancer cell inoculation in the tibia induced a significant decrease in PWL on day 8, 10 and 12 after modellng.Compared with the control group, T lymphocyte proliferation, content of T lymphocyte (CD3) and subgroups ( CD4 and CD8) in the PBS group were not significantly decreased.However, T lymphocyte proliferation and the content of CD3 lymphocytes in the model group were significantly lower than those in the blank control group and/or PBS group.Conclusions The bone cancer pain rat model may appear obvious mechanical allodynia and spontaneous pain.Its thermal pain hyperalgesiaonly occurred in the intermediate stage of bone cancer pain. The content of T lymphocytes and its subgroups, and the function of T lymphocyte proliferation are weakened to some extent in the bone cancer pain rat model.

OBJECTIVETo observe the intervention of electroacupuncture (EA) with different current frequencies and treatment frequencies on pain thresholt in rats with bone-cancer pain, so as to optimize treatment parameters of EA against bone cancer pain; and by measuring gene expression of opioid receptor and precursor in different tissues to preliminarily explore the possible mechanism of EA against bone cancer pain.

METHODSNinety healthy female SD rats were randomly divided into a control group, a model group, EA groups (6 subgroups according to different frequencies) and a sham EA group, ten rats in each one. Rats in the control group were injected with 10 µL of amicrobic phosphate buffer solution (PBS) into tibial cavity; rats in the remaining groups were injected with Walker 256 cancer cells to establish model of bone-cancer pain. No treatment was given to rats in the control group and model group; rats in the EA groups were treated with EA at bilateral "Housanli" (ST 36) and "Genduan" with 3 different current frequencies (2 Hz, 100 Hz and 2 Hz/100 Hz), once a day and once every other day, 30 min per treatment (1mA for 15 min, 2 mA for 15 min); rats in the sham EA group were treated with identical acupoints as the EA group, but the acupoints were needled subcutaneously and EA was connected with power off. All the treatment was given for 14 days. Dynamic plantar aesthesiometer was applied to measure the paw withdrawal thresholds (PWTs) of the affected side before the model establishment, 6d, 8d, 10d, 12d, 14d, 16d, 18d, and 20d after model establishment. The mRNA expressions of µ-opioid receptor (MOR), κ-opioid receptor (KOR), δ-opioid receptor (DOR), proopiomelanocortin (POMC) and prodynorphin (PDYN) in dorsal root ganglion (DRG) and lumbar spinal cord dorsal horn (SCDH) of L4-L6 of the affected side were detected by PCR method.

RESULTSThere were no differences in PWTs among all groups before model establishment (P>0. 05). Each time point after model establishment, PWTs in model group were obviously lower than those in the control group (all P<0. 01). Compared with the model group, PWTs in each EA subgroup were all increased (all P<0.05), but the differences at different time points were not significant among EA subgroups (P>0.05). The mRNA expressions of MOR, KOR, POMC, and PDYN in L4-L6 DRG in the 2 Hz/100 Hz II group were significantly higher than those in model group (P<0. 05, P<0. 01), while the mRNA expressions of MOR, KOR, DOR, POMC and PDYN in SCDH were not different compared with the model group (P>0. 05).

CONCLUSIONEA treatment has obvious analgesic effect on bone-cancer pain, however, its effect is not related with current frequency and treating frequency. EA against bone-cancer pain may be related with increasing the mRNA expression of some peripheral opioid receptors and precursor.

Acupuncture Analgesia ; instrumentation ; methods ; Acupuncture Points ; Animals ; Bone Neoplasms ; complications ; Electroacupuncture ; instrumentation ; methods ; Enkephalins ; metabolism ; Female ; Ganglia, Spinal ; metabolism ; Humans ; Pain ; etiology ; genetics ; metabolism ; Pain Management ; instrumentation ; methods ; Protein Precursors ; metabolism ; Rats ; Rats, Sprague-Dawley ; Receptors, Opioid ; genetics ; metabolism

Neuropathic pain is a chronic pain caused by primary nervous system damage and nerve dysfunction. Its pathogenesis is complex and diverse. It is difficult to treat clinically. In recent years, researchers used electroacupuncture to treat neuropathic pain and obtained a desirable effect. This article summarizes recent years’ studies on the main mechanisms of neuropathic pain and the intervention effect of electroacupuncture to provide reference for following studies on electroacupuncture treatment of neuropathic pain.

AIM AND METHODS: To explore the effects calcitonin gene-related peptide (CGRP) and endothelin-1(ET-1) on the mechanisms of hypoxic pulmonary hypertension (HPH),the contents of CGRP and ET-1 in plasma of pulmonary artery and thoracic aorta and in extractives of lung and ventricular tissues of the chronic hypoxic rats were determined by radioimmunoassay. The changes of their hemodynamic indices and right heart hypertrophy index were monitored simultaneously. RESULTS: The level of pulmonary artery plasma CGRP was significantly higher than that of thoracic aorta plasma,but just the reverse was ET-1 or the ratio of ET-1 and CGRP in control rats( P

Objective To explore the effect of low-frequency electroacupuncture (EA) on neuropathic pain induced by spinal nerve injury and its underlying mechanism.Methods Thirty-two male Sprague-Dawley rats were randomly divided into a normal group,a sham spared nerve injury (SNI) group,an SNI group and an SNI+EA group,each of 8.The rats in the SNI and SNI+EA groups were given SNI surgery,while those of the sham-SNI group only had the sciatic nerve and its branches exposed without any lesion.EA at 2 Hz was applied over the ipsilateral Zusanli and Kunlun acupoints daily for 14 days after the surgery.The ipsilateral paw withdrawal threshold (PWT) was measured,along with protein kinase A (PKA) levels in the dorsal horn of the spinal cord,calcitonin gene-related peptide (CGRP) and substance P (SP) levels along with transient receptor potential V1 (TRPV1).Results Compared to the normal group,the SNI groups all showed significant decreases in their PWTs on the affected side and significant increases in PKA,TRPV1,CGRP and substance P on the affected side.Compared to SNI group,the average ipsilateral PWT in the SNI+EA group increased significantly after EA treatment,while PKA levels,TRPV1,CGRP levels and SP expression all decreased significantly.Conclusion Electroacupuncture at low frequency can effectively relieve neuropathic pain,perhaps through down-regulation of PKA in the spinal cord and by decreasing pain hypersensitivity related to CGRP and SP.

Objective To detect the role of PAR2-PKA/PKCε signaling pathway in periphery neurons in the tran-sition from acute to chronic pain,and investigate the possible approach to prevent both acute and chronic pain simultane-ously. Methods SD rats were randomly divided into control group,sham model group,model group,iPAR2-1 group and iPAR2-2 group. The hyperalgesia priming model was established by injection of carrageenan and PGE2 into the left hind-paw except control and sham model group. PGE2 was administrated at 7 days after carrageenan injection. The PAR2 inhibi-tor was administrated before and after PGE2 injection separately in the iPAR2-1 group and iPAR2-2 group. The paw with-drawal thresholds(PWTs)of rats in each group was detected before and at 5 h,3 d,6 d,7 d 0.5 h,7 d 4 h,7 d 24 h after carrageenan injection. The expression level of PAR2, PKA and PKCε proteins in the dorsal root ganglion(DRG) were detected at 24 h after carrageenan injection. Results The hyperalgesia priming model was successfully generated. When PGE2 was administrated at 7 days after carrageenan injection, the hyperalgesia induced by PGE2 was significantly prolonged. The PWTs of rats in the model group were significantly lower than that of the control and sham model groups(P<0.01),though the PWTs of sham model group had no significant difference with the control on 7 d 24 h after carrageenan injection(P>0.05). The expression level of PAR2 and PKCε in the ipsilateral DRG neurons were significantly increased on 7 d 24 h after carrageenan injection,when compared with the control and sham model groups(P<0.05). PAR2 inhibi-tor prevented the prolonged hyperalgesia induced by PGE2(P<0.05)and decreased the PKCε expression in DRG neurons whenever it was given(P<0.05). However,PAR2 inhibitor did not regulate the acute inflammatory pain of PGE2 and the expression of PKA in DRG neurons(P>0.05). Conclusions Inhibition of the expression of PAR2 can prevent the tran-sition from acute to chronic pain. This effect may be related with the inhibitory effect on the activation of PAR2-PKCε sig-naling pathway in DRG neurons. However,inhibition of PAR2 can not regulate the acute pain. These may because of that the PAR2-PKA signaling pathway does not play a role in acute pain.