ABSTRACT
Excitatory toxicity(ET) is an important factor of neuropathic pain(NPP) induced by central sensitization(CS), and the association of pannexin-1(Panx1)-Src-N-methyl-D-aspartate receptor subunit 2 B(NMDAR-2 B) is an important new pathway for ET to initiate CS. The present study confirmed whether the central analgesic effect of Chuanxiong Rhizoma extract(CRE) was achieved through the synchronous regulation of the brain and spinal pathways of Panx1-Src-NMDAR-2 B. In this study, dynamic and simulta-neo-us microdialysis of the brain and spinal cord in vivo combined with behavioristics, high performance liquid chromatography(HPLC)-fluorescence detection, microdialysis analysis(ISCUS~(flex)), ultrasensitive multifactorial electrochemiluminescence immunoassay, ELISA, and Western blot was employed to investigate the protein expression of NMDAR-2 B, Src, and Panx1, extracellular excitatory amino acids, cytokines, energy metabolites, and substance P in spinal dorsal horn(SDH) and anterior cingulate cortex(ACC) after CRE intervention with the rat model of spared sciatic nerve injury(SNI) as the experimental tool. Compared with the sham group, the SNI group exhibited diminished mechanical withdrawal threshold(MWT)(P<0.01), increased cold spray scores(P<0.01), glutamate(Glu), D-serine(D-Ser), and glycine(Gly) in extracellular fluids of ACC, and Glu, D-Ser, interleukin-1β(IL-1β), and lactic acid(Lac) in extracellular fluids of SDH(P<0.05), dwindled tumor necrosis factor(TNF-α)(P<0.05), and elevated protein levels of NMDAR-2 B, Src, and Panx1 in ACC(P<0.05). Compared with the SNI model rats, high-and medium-dose CRE(CRE-H/M) could potentiate the analgesic activity as revealed by the MWT test(P<0.05) and CRE-M enabled the decrease in cold spray scores(P<0.05). CRE-H/M could inhibit the levels of Glu, D-Ser and Gly in the extracellular fluids of ACC(P<0.05), and the levels of Glu in the extracellular fluids of SDH(P<0.05) in SNI rats. CRE-M significantly increased the levels of glucose(Gluc), Lac, interferon-gamma(IFN-γ), keratinocyte chemoattractant/human growth-regulated oncogenes(KC/GRO), and IL-4 in extracellular fluids of SDH in SNI rats(P<0.05). CRE-H/M/L could also inhibit the levels of NMDAR-2 B, Src and Panx1 in ACC and SDH in SNI rats(P<0.05). The central analgesic effect of CRE is presumedly related to the inhibited release of excitatory amino acid transmitters(Glu, D-Ser and Gly) in ACC and SDH of SNI rats, decreased protein expression of NMDAR-2 B, Src and Panx1 in the two regions, and the regulation of the Panx1-Src-NMDAR-2 B pathway in the spinal cord and brain. The above findings partially clarified the scientific basis of clinical analgesic effect of Chuanxiong Rhizoma.
Subject(s)
Animals , Rats , Central Nervous System Sensitization , Neuralgia/drug therapy , Rats, Sprague-Dawley , Receptors, N-Methyl-D-Aspartate/metabolism , Signal Transduction , Spinal Cord/metabolismABSTRACT
Objective To investigate the effects of different concentration and inhalation duration time of isoflurane on cognitive performance and the expression of GABAR1 and NMDAR2B in aged SD rat cerebral temporal lopes.Methods Aged male SD rats (9 months) were randomly divided into control group (n=10) and test group (n=80).The control group received air at room tempreture.Test groups were divided into four groups: group S1 (1.5%-2 h),group S2 (2.5%-2 h),group S3 (1.5%-4 h),group S4 (2.5%-4 h)according to isoflurane concentration and inhalation duration time.Every group was equally divided into two groups and Morris water maze test was performed day 1 and day 7 after isoflurane inhalation.Then the right temporal lobe was gathered and the mRNA transcription and protein expression of GABAR1 and NMDAR2B were detected by RT-PCR and Immunofluorescence technique.Results One day after isoflurane inhalation, accompanied with increased isoflurane concentration and inhalation duration, the spatial memory ability of every test group decreased continually, and the mRNA transcription and protein expression of GABAR1 increased and the mRNA transcription and protein expression of NMDAR2B decreased compared with control group (P<0.01).Seven days after isoflurane inhalation, the spatial memory ability of group S4 decreased, the mRNA transcription and protein expression of both GABAR1 increased, the mRNA transcription and protein expression of NMDAR2B decreased compared with control group and the other test groups (P<0.01).There was no significant difference between the control group and groups S1, S2, S3.Conclusion Continuous inhalation of isoflurane has great effects on spatial memory ability.And impaired spatial memory by isoflurane inhalation of high concentration with long duration is present in a long time.Thoses are related with the mRNA transcription and protein expressions of GABAR1 and NMDAR2B in cerebral temporal lope.
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Objective To explore the effects of excise-induced fatigue on the microloop plasticity of prefrontal cortex through observing the expression of parvalbumin positive neurons in prefrontal cortexes of rats induced by exhaustive exercise,so as to find out the possible mechanism of the central regulation of exercise-induced fatigue by measuring the expression of NMDAR2B receptors.Methods Thirty-six Wistar rats were randomly divided into an exhausted group (E),a repeated exhaustion group (RE) and a control group (CG),each of 12.For group E,the adjusted Bedford incremental load of treadmill exercise program was employed:the initial treadmill speed was 8.2 m/min,lasting for 15 minutes,then increased to 15 m/min for another 15 minutes,and finally increased to 20 m/min till exhaustion.For RE group,they were given continuous treadmill exercises to exhaustion for consecutive 7 days.The immunofluorescence technique was used to observe the expression of PV+ interneurons after exhausted treadmill running.The Western blotting technique was used to determine the expression of NMDAR2B in the tissue of the prefrontal cortex.Results After the exhausted treadmill running,the expression of PV+ interneurons in the prefrontal cortexes of both E and RE groups increased significantly compared with the control group(P＜0.01).The immunofluorescence results indicated that NMDAR2B positive neurons were seen in group E,but not obviously in group CG and RE.The Western blotting showed that compared with CG group the protein expression of NMDAR2B in prefrontal cortexes of group E was relatively high,and that of group RE was relatively low,but without significant difference (P＞0.05).The running distance and prefrontal cortex NMDAR2B expression were found negatively correlated (P＜ 0.01).Conclusions Exhaustive exercises have an impact on the plasticity in rats' prefrontal cortex neural network through regulating the local loop of PV positive neurons.This plasticity of the prefrontal cortex is involved in the regulation of central fatigue.The present study might provide morphological basis for the research of central mechanism of the exercise-induced fatigue.
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Objective To observe the change of learning and memory quality and the expression change of GABAR1 and NMDAR2B in aged SD rat cerebral temporal lobe by propofol injection and discuss the influence that may be caused by propofol.Methods Aged male sd rats were randomly divided into three groups,each group of 20.Propofol intraperitoneal injection was implemented to groups P1 and P7 according 50 mg/kg and maintained anesthesia for 3 hours.The same dose of emulsion was given to control group. Morris water maze test was done in the first days and the seventh days after intraperitoneal injection.Then the left temporal lobe was gathered and the mRNA transcription and protein expression of GABAR1 and NMDAR2B were detected by FISH and Immunofluorescence technique.Results Compared with control group,the latent time of group P1 was significantly prolonged and the numbers of passing through the target frequency were decreased significantly (P <0.05).Group P7 had no significant differences.The mRNA transcription and protein expression of GABAR1 in group P1 were increased significantly and the mRNA transcription and protein expression of NMDAR2B in group P1 were decreased significantly (P <0.05 ). Group P7 had no significant differences.Conclusion The short-term memory of brain declined after propofol was used.This may be related to the function of temporal lobe.The mechanism may be related to the up regulation of GABAR1 and the down regulation of NMDAR2B simultaneously.
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Objective To investigate the effect of butylphthalide (NBP) on H2S content and the expression of NR2B in the hippocampus of alcohol dependence rats. Methods A total of 84 SD male rats were randomly divided into 6 groups. Except for the normal group, other groups were subjected to alcohol solution with concentration of 6% ( V/V) for 28 d. Drug intervention began at the 14th day,and rats in the low,medium,high dose group were treated with NBP with a different concentration. Erden abstinence scoring was used to evaluate the rats withdrawal symptom. H2S content was measured in one side of hippocampus and CBS activity was tested in the other side of hippocampus. Hippocampus of 3 rats from each group was used to investigate NR2B mRNA level. Results Withdrawal symptom score ( 12.27 ± 1. 19),H2S content(30. 25 ±8.82), CBS activity (72. 44 ±7. 46) and NR2B mRNA expression( 19. 47 ±0. 86) in medium dose NBP group rats were lower than withdrawal symptom score(14.09 ±2.21) ,H2S content(44. 50 ±6. 65) , CBS activity(79. 06 ±4. 57) and NR2B mRNA expression (29. 13 ±1.39) in experimental control group (P<0.05). Withdrawal symptom score(12. 18 ±1.08) ,H2S content(33.00 ±5.38) ,CBS activity(67. 81 ±9. 37) and NR2B mRNA expression(23. 12 ± 1. 86) in high dose NBP group rats were lower than experimental control group (P < 0. 05). Conclusion NBP can reduce withdrawal symptoms of alcohol dependence rats,may be related to decreased expression of H2S/CBS system, and NR2B mRNA expression.
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Objective To investigate the changes and mechanism of learning and memory in rats by different doses of benzo (a) pyrene (B(a)P). Methods Forty weaned rats (28 days) were randomly divided into control group (NS), solvent group ( vegetable oil) and three B (a) P dosage groups (the doses were 5,10 and 20 mg / kg body weight respectively ). And all rats were administrated intraperitoneally every other day to one month. The capability of learning and memory in rats were measured by Morris water maze test, and the brain-derived neurotrophic factor ( BDNF) and NMDAR2B content in hippocampus were tested by immunohistochemistry. Results In training of Morris water maze,the average escape latency was extended gradually with increasing dose, and there was a statistically significant difference between high-dose group((62. 78 ±47. 25 )s) and the control group((40.60±38.79)s)(P＜ 0.01). Compared with the control group(11.25 ±2.63), the number of crossplatform of high-dose group(4.33 ±2.08) was statistically reduced (P＜0.05). B(a)P at 10 and 20 mg/kg decreased NMDAR2B and BDNF expression in hippocampus of rats in immunohistochemistry. The level of NMDAR2B was (162.23 ±6.56) in the high-dose group and (150.38 ± 15.34) in the control group(P＜0.05);the expression level of BDNF was (163. 13 ± 8.09) in the high-dose group and (141.83 ± 13.37) in the control group(P＜ 0.05). Conclusion Subacute B(a)P exposure can reduce spatial learning and memory in weaning rats, it may be related to decreased levels of NMDAR2B and BDNF in hippocampus.