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We previously identified a unique nucleus, the cerebrospinal fluid (CSF)-contacting nucleus. This study aims to understand its gene architecture and preliminarily suggest its functions. The results showed that there were about 19,666 genes in this nucleus, of which 913 were distinct from the dorsal raphe nucleus (non-CSF contacting). The top 40 highly-expressed genes are mainly related to energy metabolism, protein synthesis, transport, secretion, and hydrolysis. The main neurotransmitter is 5-HT. The receptors of 5-HT and GABA are abundant. The channels for Cl-, Na+, K+, and Ca2+ are routinely expressed. The signaling molecules associated with the CaMK, JAK, and MAPK pathways were identified accurately. In particular, the channels of transient receptor potential associated with nociceptors and the solute carrier superfamily members associated with cell membrane transport were significantly expressed. The relationship between the main genes of the nucleus and life activities is preliminarily verified.
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Ratos , Animais , Ratos Sprague-Dawley , Serotonina/metabolismo , Transdução de Sinais , Líquido Cefalorraquidiano/metabolismoRESUMO
Objective To evaluate the role of spinal histone acetylation in persistent postoperative pain in rats. Methods Pathogen?free healthy male Sprague?Dawley rats, weighing 200-250 g, aged 2 months, in which intrathecal catheters were implanted at the lumbar level according to an improved method, were used in the study. Eighty?four rats, in which intrathecal catheters were successfully implanted, were divided intoⅠ-Ⅵgroups(n=14 each)using a random number table. Artificial cerebrospinal fluid 20 μl was intrathecally administered at 1, 2, 3 and 4 days before operation and 1 day after operation inⅠandⅣgroups. At 1, 2, 3 and 4 days before operation and 1 day after operation, dimethyl sulfoxide 10 μl and SAHA(50 μg∕10μl)were intrathecally injected inⅡandⅤgroups and inⅢandⅥgroups, respective?ly, followed by artificial cerebrospinal fluid(10 μl)flush after each injection. Rats underwent sham oper?ation inⅠ?Ⅲ groups. Persistent postoperative pain was evoked by skin∕muscle incision and traction in Ⅳ?Ⅵ groups. The mechanical paw withdrawal threshold(MWT)was measured at 1 day before operation(T0)and 1, 3, 7, 14 and 21 days after operation(T1?5). Four rats were sacrificed in each group after measurement of MWT at T4, and the lumbar segments(L4?6)of the spinal cord were removed for determi?nation of the expression of acetylated histone H3(Ac?H3)and Ac?H4 by Western blot. Results There was no significant difference in each index amongⅠ?Ⅲ groups(P>0.05). Compared with group Ⅰ, the MWT was significantly decreased at T2?5, and the expression of Ac?H3 and Ac?H4 was down?regulated at T4 in group Ⅳ(P<0.05). Compared with group Ⅳ, the MWT was significantly increased at T2?5, and the expression of Ac?H3 and Ac?H4 was up?regulated at T4in group Ⅵ(P<0.05). Conclusion Histone acetylation is involved in the development and maintenance of persistent postoperative pain in rats.
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Objective To investigate the changes in acetylation of histone in the spinal dorsal horn in a rat model of persistent postoperative pain.Methods Ninety-six malc Sprague-Dawley rats,weighing 200-250 g,aged 6-8 weeks,were randomly divided into 2 groups (n=48 each) using a random number table:sham operation group (group S) and persistent postoperative pain group (group PPP).The rat model of persistent postoperative pain evoked by skin/muscle incision and retraction was established according to the method described by Flatters.After the rats were anesthetized with intraperitoneal chloral hydrate,the skin and superficial muscle of the medial thigh were incised and retractors inserted.This tissue was retracted for 1 h.The mechanical paw withdrawal threshold (MWT) was measured at 1 day before operation and 1,3,7,14,and 21 days after operation.Four animals were sacrificed in each group after measurement of MWT at each time point for detection of acetylated histone H3 (Ac-H3) and acetylated histone H4 (Ac-H4) expression (by Western blot analysis) and the number of Ac-H3 and Ac-H4 positive cells in the spinal cord horn (by immunofluorescence histochemistry).Results Compared with group S,the MWT was significantly decreased at 3,7,14 and 21 days after operation,the expression of Ac-H3 and Ac-H4b was significantly down-regulated at 3,7 and 14 days after operation,and the number of Ac-H3 and Ac-H4 positive cells was significantly decreased at 7,14 and 21 days after operation in group PPP (P＜0.05 or 0.01).The MWT,expression of Ac-H3 and Ac-H4b,and the number of Ac-H3 and Ac-H4 positive cells were significantly higher at 21 days after operation than at 14 days after operation in group PPP (P＜0.05).Conclusion Acetylation of histone in the spinal dorsal horn is decreased after operation,which may be involved in the development and maintenance of persistent postoperative pain in rats.
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Objective To evaluate the effects of hydrogen-rich saline on chronic inflammatory pain in rats.Methods Thirty-two male Sprague-Dawley rats,aged 8-10 weeks,weighing 200-250 g,were randomly divided into 4 groups (n =8 each) using a random number table:control group (group C);complete Freund's adjuvant (CFA) group;hydrogen-rich saline group (group H2);CFA + hydrogenrich saline group (CFA+H2 group).Chronic inflammatory pain was induced by injecting CFA 100 μl into the plantar surface of the left hindpaw in CFA and CFA + H2 groups.In H2 and CFA + H2 groups,0.6 mmol/L hydrogen-rich saline 5 ml/kg was injected intraperitoneally once a day for 7 consecutive days starting from 1 day after injection of CFA,while the equal volume of normal salinc was given instead of hydrogen-rich saline in C and CFA groups.The mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured at 1 day before CFA injection and 1,3 and 7 days after CFA injection.The rats were sacrificed after the last measurement of pain threshold on day 7 after CFA injection.The left lumbar segments (L4 5) of the spinal cord were removed for determination of nuclear factor E2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) expression by Western blot.Results Compared with C group,no significant change was found in the MWT,TWL and expression of Nrf2 and HO-1 in H2 group,and the MWT was significantly decreased,the TWL was shortened,and the expression of Nrf2 and HO-1 was up-regulated in CFA and CFA+H2 groups.Compared with CFA group,the MWT was significantly increased,the TWL was prolonged,and the expression of Nrf2 and HO-1 was up-regulated in CFA+H2 group.Conclusion Hydrogen-rich saline can alleviate chronic inflammatory pain in rats,and activation of Nrf2/ARE signaling pathway in the spinal cord is involved in the mechanism.
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Objective To evaluate the effects of intrathecal 2-PMPA on chronic inflammatory pain in rats . Methods Twenty four male Sprague-Dawley rats ,aged 4-6 months ,weighing 200-250 g ,were randomly divided into 3 groups (n=8 each) using a random number table :normal saline (NS) group ,complete Freund′s adjuvant (CFA ) group and N-acetylaspartylglutamate peptidase inhibitor 2-PMPA group (group 2-PMPA ) . Chronic inflammatory pain was induced by injecting 100μl of CFA into the plantar surface of the left hindpaw .Immediately after injection of CFA ,2-PMPA 100 μg was injected intrathecally once a day for 3 consecutive days in group 2-PMPA ,while the equal volume of NS was given instead of 2-PMPA in NS and CFA groups .The paw withdrawal latency to thermal nociceptive stimulus (TWL ) and paw withdrawal threshold (PWT ) to von Frey filament stimulation were measured before injection of CFA (baseline ,T1 ) and after the last injection of CFA (T2 ) .Then the rats were sacrificed and the L4 ,5 segments of the spinal cord were removed for determination of NR2B expression by Western blot .Results Compared with group NS ,TWL and PWT were significantly decreased at T2 and the expression of NR2B was up-regulated in CFA and 2-PMPA groups ( P<0.05 ) .Compared with group CFA ,TWL and PWT were significantly increased at T2 and the expression of NR2B was down-regulated in group 2-PMPA ( P<0.05) .Conclusion Intrathecal 2-PMPA can alleviate CFA-induced chronic inflammatory pain in rats ,and inhibition of NR2B expression in the spinal cord is involved in the mechanism .
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Objective To investigate the roles of spinal N-methyl-D-aspartic acid receptor-extracellular signal-regulated protein kinases 5 signaling pathway in naloxone-induced withdrawal response in morphine-dependent rats.Methods Ninety-six adult male SD rats weighting 230-250 g were randomly divided into 4 groups:control group,withdrawal group,DMSO group and MK801 group.Rats were subcutaneously injected with morphine.On day 6,rats were injected with naloxone (intraperitoneal) to precipitate morphine withdrawal syndromes.To identify the function of NMDAR-ERK5 signaling pathway in morphine withdrawal,morphine withdrawal-like behavior test and western blot technique were used in this research.The scores of morphine withdrawal symptom,morphine withdrawal-induced allodynia and the activation of ERK5 in spinal cord were observed after intrathecal injection of MK801.Results There was no withdrawal symptoms and withdrawal-induced allodynia in group A after intraperitoneal injection of naloxone.Compared with group A,withdrawal score (45.2±7.3),score of withdrawal-induced allodynia (14.4±3.7) of group B,withdrawal score (44.7±6.2),score of withdrawal-induced allodynia (13.2±2.7) of group C and withdrawal score (28.3±1.6),score of withdrawal-induced allodynia (5.9± 1.1) of group D were significantly increased (P＜ 0.05).Compared with group C,the total withdrawal score (28.3 ± 1.6),score of withdrawal-induced allodynia (5.9± 1.1) of group D were significantly decreased (P＜0.05).Compared with group A,the expression of spinal p-ERK5 of group B (12848±621) and group C (12579±396) were significantly increased (P＜0.05).Compared with group C,the expression of spinal p-ERK5 of group D (5 123±546) was significantly decreased (P＜0.05).Condusion The signaling pathway of spinal N-methyl-D-aspartic acid receptor-extracellular signal-regulated protein kinases 5 contributes to naloxone-induced withdrawal response in morphine-dependent rats.
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Objective To evaluate the role of spinal neuronal extracellular signal-regulated protein kinases 5/cAMP response element binding protein (ERK5/CREB) signaling pathway in withdrawal responses in morphinedependent rats.Methods Ninety-six adult male Sprague-Dawley rats in which intrathecal catheters were successfully placed,weighing 200-250 g,were randomly divided into 4 groups (n =24 each):normal control group (group A),morphine withdrawal group (group B),dimethyl sulfoxide (DMSO) + morphine withdrawal group (group C) and ERK5 inhibitor BIX02188 + morphine withdrawal group (group D).Morphine dependence (MD) was induced by increasing doses of subcutaneous morphine for 6 days.The initial dose of morphine was 10 mg/kg once a day and was increased by 10 mg/kg once a day from 2nd to 5th days until 50 mg/kg on 6th day in B,C and D groups.Morphine withdrawal response (MW) was induced by intraperitoneal naloxone 4 mg/kg at 4 h after last morphine administration in B,C and D groups.In addition,BIX02188 10 μg and 1％ DMSO 10 μl were injected intrathecally at 1 h before naloxone injection in D and C groups,respectively.MW and morphine withdrawal-induced hyperalgesia were scored.The rats were then sacrificed after hyperalgesia was scored and the spinal cord was removed for determination of CREB and phosphorylated CREB (p-CREB) expression.Results Compared with group A,MW and hyperalgesia scores were significantly increased and the expression of p-CREB was up-regulated in B,C and D groups.Compared with group B,MW and hyperalgesia scores were significantly decreased and the expression of p-CREB was down-regulated in D group,and no significant change was found in group C.Conclusion The spinal neuronal ERK5/CREB signaling pathway is involved in withdrawal responses in morphine-dependent rats.
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Aim To explore the role of KATP in the pa-raventricular nucleus in inflammatory pain. MethodsMale Sprague-Dawley rats,250~280 g, were randomly assigned into 5 groups ( each, n =6 ): Normal group, Saline group ( for control, subcutaneous injection of 100 μl of saline into the plantar surface of the left hindpaw) , CFA group ( subcutaneous injection of 100μl of complete freund's adjuvant into the plantar sur-face of the left hindpaw) , Vehicle group ( treated with dimethylsulfoxide), KATP selective agonist group(trea-ted with diaoxide) . Rats in each group were tested for TWL with radiant heat apparatus. Immunofluorescent technique was used to label KATP in PVN and c-Fos in lumber spinal cord. Three days after injected with CFA, a selective KATP agonist, diaoxide, was injected into one side of PVN to test its effect on inflammatory pain and c-Fos expression in lumber spinal cord. Re-sults ① Compared with pre-operation and saline group, rats showed significantly lower TWL on day 1, 3, 7 after injection of CFA;the numbers of KATP posi-tive cells were significantly lower; the numbers of c-Fos positive cells were significantly higher. ② Com-pared with those of vehicle group, TWL and the num-ber of c-Fos in lumber spinal cord were both signifi-cantly lower after injection of diaoxide into one side of PVN. Conclusion KATP in PVN is related to inflam-matory pain.
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Objective To evaluate the changes in the activity of extracellular signal-regulated kinase 5 (ERK5) in the distal cerebrospinal fluid contacting neurons (CSF-CNs) in the mid-brain of morphine dependent rats.Methods Forty-eight male adult Sprague-Dawley rats weighing 230-270 g,were randomly divided into 2 groups (n =24 each) using a random number table:control group (group A) and morphine dependence group (group B).Morphine dependence was induced by increasing doses of subautaneous morphine for 5 consecutive days.The initial dose of morphine was 10 mg/kg twice a day and was increased by 10 mg/kg everyday until 50 mg/kg on 5th dav.The equal volume of normal saline was injected subcutaneously instead of morphine in group A.On 3rd day after morphine dependence was induced,the distal CSF-CNs in the mid-brain was labeled with 30％ cholera toxin subunit B and horseradish peroxidase compound (CB-HRP) 3 μl injected in the lateral cerebral ventricle in the morning.At 4 h after the last injection of morphine,the segments in which CSF-CNs were located were removed,and CB-HRP positive neurons,phosphor-ERK5 (p-ERK5) positive neurons and CB-HRP/p-ERK5 positive neurons were counted.Results Compared with group A,the number of p-ERK5 and CB-HRP/p-ERK5 positive neurons in the mid-brain was significantly increased (P ＜ 0.05),and no significant change was found in CB-HRP positive neurons in group B (P ＞ 0.05).Conclusion The enhanced activity of ERK5 in the distal CSFCNs in the mid-brain may contribute to the development of morphine dependence in rats.
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Objective To evaluate the role of extracellular signal-regulated protein kinase 5 (ERK5) in the spinal cord in withdrawal responses in morphine-dependent rats.Methods Ninety-six adult male SpragueDawley rats in which intrathecal catheters were successfully placed,weighing 200-250 g,were randomly divided into 4 groups (n =24 each) using a random number table:normal saline group (group A),withdrawal group (group B),dimethyl sulfoxide (DMSO) group (group C) and ERK5 inhibitor BIX02188 group (group D).Morphine dependence (MD) was induced by increasing doses of subcutaneous morphine for 6 days.The initial dose of morphine was 10 mg/kg once a day and was increased by 10 mg/kg once a day from the 2nd to 5th days until 50 mg/kg on the 6th day in B,C and D groups.Morphine withdrawal response (MW) was induced by intraperitoneal naloxone 4 mg/kg at 4 h after last morphine administration in B,C and D groups.In addition,BIX02188 and 1％ DMSO 10 μl were injected intrathecally at 1 h before naloxone injection in D and C groups,respectively.MW and morphine withdrawal-induced hypemlgesia were scored.The rats were then sacrificed after hyperalgesia was scored and the spinal cord was removed for determination of ERK5 and phosphorylated ERK5 (p-ERK5) expression.Results Compared with group A,MW and hyperalgesia scores were significantly increased and the expression of pERK5 was up-regulated in B,C and D groups (P ＜ 0.05).Compared with group B,MW and hyperalgesia scores were significantly decreased and the expression of p-ERK5 was down-regulated in D group (P ＜ 0.05),and no significant change was found in group C (P ＞ 0.05).Conclusion ERK5 in the spinal cord is involved in withdrawal responses in morphine-dependent rats.
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Objective To evaluate the role of cerebrospinal fluid-contacting nuclei (CSF-CN) in maintenance of chronic itch in rats.Methods Forty-two adult male Sprague-Dawley rats,aged 3 months,weighing 240-280 g,were used in the study.The experiment was performed in two parts.Part Ⅰ Forty-two Sprague-Dawley rats were randomly divided into 3 groups (n =14 each):control group (C group),acetone group (A group) and oxazolone group (O group).0.5％ oxazolone 15 μl was applied to the neck and back of rats in group O,while the equal volume of normal saline and acetone was applied in groups C and A,respectively.Application of the drug mentioned above was repeated on day 7,9,13,16,17,18,21 and 23 after the first stimulation in each rat in each group.Scratching behaviors were oberserved within 30 min after each stimulaiton.Six rats in each group were chosen and sacrificed after the last application of oxazolone,and the brains were obtained for determination of c-Fos expression in CSF-CN.Part Ⅱ Twenty-four rats were randomly divided into 3 groups (n =8 each):control group (C1 group),chronic itch group (group CI),and chronic itch + lesion group (CI + KA group).Chronic itch was induced by repeated application of oxazolone as previously described in CI and CI + KA groups.The chemical lesion of CSF-CN was performed at 6 h after 8th application of the drug.Then the scratching behaviors were observed within 30 min after 9th application of the drug.Results Part Ⅰ Compared with C group,the scratching behaviors were increased significantly at T4-8 in A group,and at T1-8 in O group (P ＜ 0.05),and the expression of c-Fos was up-regulated in O and A groups (P ＜ 0.05).Compared with A group,the scratching behaviors were increased significantly at T1-8 and the expression of c-Fos was up-regulated in O group (P ＜ 0.05).Part Ⅱ Compared with C1 group,the scratching behaviors were significantly increased in CI and CI + KA groups (P ＜ 0.05).The scratching behaviors were significantly reduced in CI + KA group compared with CI group (P ＜ 0.05).Conclusion CSF-CN is involved in the maintenance of chronic itch in rats.
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Objective To investigate the roles of spinal extracellular signal-regulated protein kinases 5 (ERK5) on morphine withdrawal in rats.Methods Ninety-six male and adult SD rats weighting 230-250 g were randomly divided into saline-naloxone-DMSO group (group A),saline-naloxone-BIX02188 group (group B),morphine-naloxone-DMSO group (group C) and morphine-naloxone-BIX02188 group (group D).To set up morphine dependent model,rats were subcutaneously injected with morphine in the increasing dosage method.On day 6,4 h after the injection of morphine,rats were injected with naloxone (intraperitoneal) to precipitate morphine withdrawal syndrome.The scores of morphine withdrawal symptom and morphine withdrawal-induced allodynia were observed after intrathecal injection of ERK5 inhibitor BIX02188.Result There were not withdrawal symptoms and withdrawal-induced allodynia in group A and B after intraperitoneal injection of naloxone.Compared with group A,teeth chatting (7.5± 1.1),wet dog shacks (4.6± 0.7),jump (5.3± 0.7),abnormal position (8.9± 1.9),diarrhea (7.1 ± 1.6),salivation (2.8±0.6),weight loss (7.9±0.9),total withdrawal score (44.8±5.9),score of withdrawalinduced allodynia (14.6±2.4) of group C and teeth chatting (3.1±0.5),wet dog shacks (1.5±0.4),jump (2.2± 0.5),abnormal position (7.9± 1.6),diarrhea (1.8±0.5),salivation (2.8±0.9),weight loss (3.7±0.6),total withdrawal score (23.1± 1.3) and score of withdrawal-induced allodynia (3.5± 1.1) of group D were significantly increased (P＜0.05).Compared with group C,teeth chatting (3.1±0.5),wet dog shacks (1.5±0.4),jump (2.2±0.5),diarrhea (1.8±0.5),weigbt loss (3.7±0.6) and total withdirawal score (23.1±1.3),score of withdrawal-induced allodynia (3.5±1.1) of group D were significantly decreased (P＜0.05).But there was not significant change in abnoral position (7.9±1.6) and salivation (2.8±0.9).Conclusion Inhibition of the activation of spinal cord ERK5 can significantly alleviate withdrawal symptoms of morphine dependent rats by intrathecal injection BIX02188.
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Objective To evaluate the changes in the expression of Nogo-A protein in the dorsal root ganglion (DRG) and spinal dorsal horn in a rat model of inflammatory pain.Methods One hundred and twenty male Sprague-Dawley rats,weighing 250-300 g,were randomly divided into 2 groups (n =60 each):control group (group C) and formalin group (group F).The inflammatory pain was induced by injection of 3％ formalin 100 μl into the plantar surface of left hindpaw in group F.The equal volume of normal saline was given instead of formalin in group C.Mechanical withdrawal threshold to yon Frey filament stimulation was measured at 1 h and 1,2,3 and 7 days after injection.Twelve rats in each group were chosen at each time point and sacrificed.The L5 DRG and L4,5 segment of spinal cord on the operated side were removed for determination of Nogo-A protein expression by immunofluorescence and Western blot.Remlts Compared with group C,the mechanical withdrawal threshold was significantly decreased at 1 h,1,2,3 and 7 days after injection,and the expression of Nogo-A protein in the DRG and L4,5 segment of spinal cord was up-regulated at 1 h and 2,3 and 7 days after injection in group F (P ＜0.05).Conclusion Up-regulation of Nogo-A protein in the DRG and spinal dorsal horn may play an important role in the development of formalin-induced inflammatory pain in rats.
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Objective To investigate the changes in the expression of Nogo-A protein in the dorsal root ganglion (DRG) and spinal dorsal horn in a rat model of neuropathic pain (NP) .Methods Seventy-two male SD rats weighing 250-300 g were randomly divided into 3 groups ( n = 24 each) : control group (group C) , sham operation group (group S) and NP group. NP was induced by ligation and severance of tibial and common fibular nerves according to the technique described by Isabelle et al. The mechanical withdrawal threshold (MWT) to von Frey filament stimulation was measured at 1, 7, 14 and 21 days after ligation. Six rats in each group were randomly selected at each time point and sacrificed (3 for determination of Nogo-A protein expression by immunofluorescence, 3 for determination of Nogo-A protein expression by Western blot) . The L5 DRG and L4,5 segment of spinal cord on the injured side were removed for determination of Nogo-A protein expression by immunofluorescence and Western blot. Results Compared with the groups C and S, MWT was significantly decreased at 7, 14 and 21 days after ligation, the expression of Nogo-A protein in the DRG was down-regulated at 7 and 14 days after ligation and the expression of Nogo-A protein in the spinal dorsal horn was up-regulated at 14 and 21 days after ligation ( P ＜0.05) .Conclusion The Nogo-A protein in the DRG and spinal dorsal horn may play an important role in peripheral nerve injury-induced NP in rats.
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Objective To evaluate the role of 5-HT1A receptors in distal cerebrospinal fluid (CSF)-contacting neurons in neuropathic pain (NP) in rats. Methods Forty male SD rats weighing 230-270 g were randomly divided into 4 groups (n = 8 each): sham operation group (group S); NP group; dimethyl sulfoxide (DMSO) group and 8-OH-DPAT (a specific 5-HT1A receptor agonist) group. NP was induced by chronic constrictive injury (CCI) in groups NP, DMSO and 8-OH-DPAT. Four silk ligatures were placed on the sciatic nerve at 1 mm intervals . In group S, the sciatic nerve was exposed but not ligated. 8-OH-DPAT and DMSO 1 μl were injected into the region where most of CSF-contacting neurons are present over 5 min on 7th day after CCI in groups 8-OH-DPAT and DMSO respectively. Paw withdrawal latency (PWL) and paw withdrawal threshold (PWT) were measured before CCI, on 7th day after CCI, and at 3 and 6 h after administration. The rats were sacrificed 6 h after administration, and the brain tissues removed for determination of the expression of 5-HT1A receptors in the distal CSF-contacting neurons by immunofluorescence. Results Compared with group S, PWL was significantly shorten and PWT decreased at T, in groups NP, DMSO and 8-OH- DPAT (P ＜ 0.01) . Compared with group DMSO, PWL was significantly prolonged and PWT increased at T2 and T3 in group 8-OH-DPAT ( P ＜ 0.01). The 5-HT1A receptor expression was significantly down-regulated in groups NP and DMSO compared with group S, while up-regulated in group 8-OH-DPAT compared with groups NP and DMSO ( P ＜ 0.01). There was no significant difference in 5-HT1A receptor expression between groups NP and DMSO ( P ＞ 0.05). Conclusion 5-HT1A receptors in distal CSF-contacting neurons are involved in the regulation of NP in rats.
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Objective To investigate the effect of tramadol on the expression of 5-HT1A receptor in the distal'cerebrospinal fluid contacting neurons (CSF-CNs) in mid-brain in a rat model of neuropathic pain. Methods Forty male SPF SD rats weighing 220-280 g were randomly divided into 5 groups (n = 8 each): group Ⅰ normal control (group C); group Ⅱ normal saline (group NS); group Ⅲ tramodol (group T); group Ⅳ neuropathic pain + normal saline (group NP+ NS) and group Ⅴ neuropathic pain + tramadol (group NP + T). Neuropathic pain was induced by chronic constrictive injury (CCI) in group Ⅳ and Ⅴ . Four silk ligatures were placed on the sciatic nerve at 1 mm intervals. In group Ⅱ (NS) and group Ⅲ (T) the sciatic nerve was exposed but not ligated and NS 2 ml/kg and tramadol 10 mg/kg were injected IP respectively, while in group Ⅳ and Ⅴ NS 2 ml/kg and tramadol 10 mg/kg were injected IP respectively on the 7th day after CCI. Paw withdrawal threshold (PWT) to von Frey filament stimulation and paw withdrawal latency (PWL) to noxious thermal stimuli were measured before (T1) and after IP NS or tramadol injection (T2) in group Ⅱ-Ⅴ. The distal CSF-CNs in the mid-brain was labelled with 30% cholera toxin subunit B and horseradish peroxidase compound (CB-HRP) 3 μl injected in left lateral cerebral ventricle. The expression of 5-HT1A receptors was measured by immuno-histochemistry. Results PWT and PWL were significantly decreased after CCI in group Ⅳ (NP + NS) and tramadol significantly inhibited the mechanical and thermal hyperalgesia in group Ⅴ (NP + T). There was no significant difference in the number of distal CSF-CNs among the 5 groups. CCI significantly down-regulated the expression of 5-HT1A in distal CSF-CNs in group Ⅳ(NP+ NS) as compared with group Ⅰ , Ⅱ and Ⅲ and tramadol significantly inhibited the CCI-induced downregulation of 5-HT1A receptor expression. Conclusion Tramadol can ease neuropathic pain by down-regulating the expression of 5-HT1A receptor in distal CSF-CNs in mid-brain.
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Basing on the introductions to the three levels about the health statistics,including the concept of staffstics,the overview of the health statistics development and the current status of the Health Statistics on Traditional Chinese Medicine,we discuss the significance of Health Statistics on Traditional Chinese Medicine and analysis its existing problems,possible reasons and solutions.
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BACKGROUND: It is indistinct that whether ketamine can exert antinociceptive effect througb influencing the transmission of nocuous information in spinal cord; Nitric oxide (NO) in spinal cord participates mainly in the formation and development of hyperalgesia, and it can also induce Fos protein expression. It is still controversal whether it contributes to the transmission and mediation of ketamine to pain signal.OBJECTIVE: To observe the response to formalin stimulation in spinal cord of the rats and the effect of ketamine.DESIGN: Balanced randomized animal trial.SETTING: Department of Anesthesiology, Affiliated Hospital of Xuzhou Medical College; Jiangsu Provincial Key Laboratory of Anesthesiology.MATERIALS: This trial was carried out in the Jiangsu Provincial Key Laboratory of Anesthesiology, Xuzhou Medical College from January to March 2000. Totally 30 Sprague-Dawley rats were chosen and balanced randomized into 6 groups: formalin group (n=6), formalin + ketamine group (n=6), ketamine +formalin group (n=6), ketamine group (n=6), formalin+normal saline group (n=3) and normal saline group (n=3). The gender ratio was the same in each group.METHODS: Formalin group:The rats were stimulated for one hour by subcutaneous injection of 0.05 volume fraction of 200 μL in the center of palm of unilateral fore-claw. Formalin +ketamine group: The rats were stimulated for 10 minutes by formalin, then for one hour by intraperitoneal injection of 100 rg/kg ketamine. Ketamine + formalin group: The rats were injected with ketamine for 10 minutes, then with formalin for one hour. Ketamine group: the same dosage of ketamine was intraperitoneally injected into the rats for one hour. Formalin + normal saline group: The rats were stimulated for 10 minutes by formalin, then intraperitoneally given 10 mL/kg normal saline for one hour. Normal saline group: the same volume of normal saline was intraperitoneally injected into the rats for one hour.MAIN OUTCOME MEASURES: ① Behavioral performance of the rats in each group. ② Spinal sections were chosen, and stained with c-fos genetic immunohistochemical and NADPH-d histochemical methods. The changes of the number of Fos-like immuno-positive neurons (FLI) and FLI/nitric oxide synthase (NOS) double-labeled neurons in the 4-layer sections (layer Ⅰ -Ⅱ ,layer Ⅲ-Ⅳ ,layerⅤ-Ⅵ ,layer Ⅶ-X )of spinal dorsal horn of the rats were observed.RESULTS: All the thirty rats entered the stage of result analysis. ① Behavioral changes: The rats of formalin group and formalin+ normal salinegroup had apparent pain response; Several minutes after injection with ketamine, righting reflex disappeared and did not recover at perfusion period.Prolonged sleep was found without obvious pain response performance. ② FLI neuron expression: A lot of FLI positive neurons were found in the spinal dorsal horn of injec tion side of the rats in the formalin group and formalin+ normal saline group, and they distributed principally in the layer Ⅰ - Ⅱ of spinal dorsal horn.The distribution in the ketamine + formalin group and formalin + ketamine group was basically similar to that in the formalin group and formalin + normal saline group, but positive neuron counts were significantly reduced (P ＜ 0.01). ③ The expression of FLI/NOS double-labeled neurons: The number of double-labeled neurons in the spinal dorsal horn layer Ⅰ - Ⅱ of the rats in the ketamine+ formalin group and formalin+ ketamine group were significantly less than that in the formalin group and formalin+normal saline group [(1±1), (1±1), (7±3), (8±3),P ＜ 0.01].CONCLUSION: Some neurons of ipsilateral corresponding spinal segments participate in the transmission and mediation of pain signal. Ketamine can suppress the activities of these neurons and exert antinociceptive effect. The antinococeptive function of ketamine may be caused by the activity depression of the NOS-positive neurons in spinal cord.
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Aim To observe the neuron nitric oxide synthase(nNOS) expression in the distal cerebrospinal fluid contacting neurons(CSF-CNs) of rat brain parenchyma, and investigate the role of CSF-CNs in the development of morphine dependence and withdrawal.Methods Male adult Sprague-Dawley rats, weighed 260?20 g,were experimented with A 3 ?l volume of 30% cholera toxin subunit B with horseradish peroxidase(CB-HRP) was injected into one of the rats′lateral ventricles to trace and locate the distal CSF-CNs of rat brain parenchyma 48 hours before the animals were killed. All animals were perfused and the relative tissue of rats′brain was removed.Frozen serial coronal sections (40 ?m) were cut. Then TMB-ST reaction procedure was used to stain the CB-HRP positive neurons,followed by immunohistochemistry double-labeling of the nNOS with CB-HRP positive neurons. The withdrawal symptoms were observed and scored. The numbers of the CB-HRP, and CB-HRP/nNOS positive neurons on the same segmental brain sections were counted.Results The withdrawal symptoms of the withdrawal group were significant, scores of all signs were significantly higher than those of the dependence groups and control group(P
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TRP(transient receptor potential) ion channel is a kind of membrane proteins which are widespreadly present in various cells,which is used to identify various mixed flavor and warm,heat,cold,and other temperature.Originally cloned as a proatate-specific protein.TRPM8 is now best known as a cold-and menthol-activated channel implicated in thermosensation.We provide a brief review of current knowledge concerning the biophysical properties,gating mechanisms,pharmacology and(patho)physiology of this TRP channel.