Stargazin在切口痛大鼠脊髓背角GluR1-AMPA受体胞浆至胞膜转运中的作用

目的 评价Stargazin在切口痛大鼠脊髓背角含谷氨酸受体1亚基的使君子酸(GluR1-AMPA)受体胞浆至胞膜转运中的作用.方法 成年雄性清洁级SD大鼠45只,体重280 ～ 300 g,6～8周龄,采用随机数字表法,将其分为5组:正常对照组(C组)、假手术组(S组)、切口痛+生理盐水组(P组)、切口痛+ Stargazin小干扰RNA(siRNA)组(I组)和切口痛+Stargazin无意义siRNA组(N组).P组、I组和N组分别鞘内注射生理盐水10μl、20 μmol/L siRNA、20μmol/L无意义siRNA 10μl,2次/d,连续3d,4d后制备右足底切口痛模型.切口痛术后3h时测定大鼠累计痛评分(CPS)和机械缩足阈(PWT).然后处死大鼠,取L3-6节段脊髓背角,采用Westem blot法检测胞浆和胞膜GluR1和GluR2亚基表达,采用免疫共沉淀技术检测脊髓背角Stargazin与GluR1或GluR2亚基的共表达.结果 与C组比较,P组和N组CPS评分升高,PWT降低,脊髓背角胞浆GluR1表达下调,脊髓背角胞膜GluR1表达上调,I组CPS评分升高(P＜0.05或0.01);与P组比较,I组CPS评分降低,PWT升高,脊髓背角胞浆GluR1表达上调,脊髓背角胞膜GluR1表达下调,脊髓背角Stargazin和Stargazin与GluR1共表达下调(P＜ 0.05或0.01).结论 Stargazin介导了切口痛大鼠GluR1-AMPA受体从胞浆至胞膜转运.     

AMPA受体介导的突触可塑性与药物依赖

突触可塑性改变是形成药物依赖长期效应的病理基础,兴奋性氨基酸受体在其中起十分重要的作用。近年来的研究表明,多种药物依赖过程与AMPA受体有关。联系药物依赖所致的AMPA受体的变化与神经元的可塑性改变,探讨AMPA受体介导药物依赖的形成机制,可为进一步理解AMPA受体在药物依赖中的作用提供帮助。     

异丙酚对内脏痛大鼠脊髓背角使君子酸受体GluR1亚基磷酸化水平的影响

目的 探讨异丙酚对内脏痛大鼠脊髓背角使君子酸(AMPA)受体谷氨酸受体1(GluRl)亚基831和845位点丝氨酸磷酸化水平的影响.方法 成年雄性SD大鼠,体重200～300 g,6～8周龄,行鞘内置管术,5d后选取鞘内置管成功的大鼠30只,采用随机数字表法,将其随机分为3组(n=1 0):假手术组(Ⅰ组)、内脏痛组(Ⅱ组)和异丙酚组(Ⅲ组).Ⅱ组和Ⅲ组采用经直肠注射50μl10％辣椒素的方法制备内脏痛模型,Ⅰ组给予等容量生理盐水,Ⅲ组于给予辣椒素前10 min鞘内注射异丙酚20μg,Ⅰ组和Ⅱ组给予等容量二甲基亚砜.记录给予辣椒素后30 min内大鼠累计痛评分,然后处死大鼠,取L3-6腰骶段脊髓背角组织,采用免疫印迹法检测AMPA受体GluR1亚基及其831和845位点丝氨酸磷酸化水平.结果与Ⅰ组比较,Ⅱ组和Ⅲ组累计痛评分和脊髓背角GluR1亚基831和845位点丝氨酸磷酸化水平升高(P ＜0.05或0.01),而GluR1亚基表差异无统计学意义(P＞0.05);与Ⅱ组比较,Ⅲ组累计痛评分和脊髓背角GluR1亚基831和845位点丝氨酸磷酸化水平降低(P＜0.05或0.01).结论 异丙酚可减轻大鼠内脏痛,其机制与抑制脊髓背角AMPA受体GluR1亚基831和845位点丝氨酸磷酸化有关.     

切口痛大鼠脊髓背角GluR1-AMPA受体和GluR2-AMPA受体胞浆至胞膜转运的变化

目的 探讨切口痛大鼠脊髓背角含谷氨酸受体1亚基的使君子酸(GluR1-AMPA)受体和含谷氨酸受体2亚基的使君子酸(GluR2-AMPA)受体胞浆至胞膜转运的变化.方法 成年雄性清洁级SD大鼠32只,体重280～ 300 g,6～8周龄,采用随机数表法,将其随机分为2组:正常对照组(C组,n=8)和切口痛组(Ⅰ组,n=24).Ⅰ组大鼠制作右足底切口痛模型.Ⅰ组于术后3h、1d和3d时取8只大鼠,测定累计痛评分(CPS)和机械缩足阈值(PWT).然后处死大鼠,取L3～6节段脊髓背角,采用Western blot法检测胞浆和胞膜GluR1和GluR2亚基的表达,采用免疫共沉淀技术检测脊髓背角Stargazin与GluR1或GluR2亚基的共表达.结果 与C组比较,Ⅰ组CPS评分升高,PWT降低,脊髓背角胞浆GluR1亚基表达下调,脊髓背角胞膜GluR1表达及Stargazin与GluR1共表达上调(P＜0.05或0.01),脊髓背角胞浆和胞膜GluR2及Stargazin与GluR2共表达差异无统计学意义(P＞0.05).结论 切口痛大鼠脊髓背角GluR1-AMPA受体从胞浆转运至胞膜,而GluR2-AMPA受体不发生胞浆至胞膜的转运.     

神经突触中枢神经突触膜相关鸟甘酸激酶锚定蛋白参与疼痛调节的研究进展

背景 中枢神经突触膜相关鸟苷酸激酶(membrane-associated guanylate kinase,MAGUK)蛋白家族包含4种突触相关蛋白:PSD-93、PSD-95、SAP-102、SAP-97,它们参与调节谷氨酸突触信号传递,与学习记忆和疼痛等有关. 目的综述神经突触MAGUK锚定蛋白与疼痛相关受体和分子之间的相互作用及其在疼痛信号调节及传递中的作用. 内容 神经突触MAGUK锚定蛋白可通过与N-甲基-D-天冬氨酸(N-methyl-D-aspartate,NMDA)受体、神经元型一氧化氮合酶(neuronal nitric oxide synthase,nNOS)、使君子酸(α-amino-3-hydroxy-5-methy-4-isoxazole propionate,AMPA)受体以及突触细胞黏附分子(synaptic cell-adhesion molecules,Syn CAM)等相互作用参与调节疼痛信号在突触的传递,影响突触传递强度. 趋向 干扰神经突触MAGUK锚定蛋白与疼痛相关受体和重要分子间的相互作用可影响疼痛信号在突触的传递,是疼痛治疗的新靶点.     

NMDA受体2B亚基:一个潜在的镇痛治疗靶点

N甲-基-D天-冬氨酸(N-methyl-D-aspartate,NM-DA)受体是一种配体门控离子型谷氨酸受体,参与体内神经发育、突触可塑性、学习记忆以及痛觉信号的转导等生理病理过程。组成NMDA受体的亚基按基因型分为:NR1、NR2(A、B、C和D)和NR3(A和B)3个家族,其中NR1为必需功能亚基,NR2属于调节     

成年和老龄大鼠神经肌肉接头处突触后膜乙酰胆碱受体表达和分布的比较

目的 比较成年和老龄大鼠神经肌肉接头处突触后膜乙酰胆碱受体表达和空间分布的差异.方法 健康雄性Wistar大鼠10只,按月龄分为成年组(4～6月龄,n=5)和老龄组(24～28月龄,n=5),提取大鼠腓肠肌总RNA.根据编码大鼠烟碱型乙酰胆碱受体ε亚单位的mRNA序列,设计引物并合成引物对,采用实时定量PCR技术测定腓肠肌组织烟碱型乙酰胆碱受体ε亚单位mRNA表达量.用四甲基罗丹明-α-银环蛇毒标记大鼠神经肌肉接头处突触后膜乙酰胆碱受体,采用激光共聚焦显微镜激发标记物发光,观察受体分布情况,并测定受体分布区的面积、长度和宽度.结果 与成年组比较,老龄组大鼠腓肠肌烟碱型乙酰胆碱受体ε亚单位mRNA表达量降低(P＜0.05),突触后膜乙酰胆碱受体分布区面积、长度和宽度差异无统计学意义(P＞0.05).两组大鼠突触后膜乙酰胆碱受体分布形态存在明显差异.结论 老龄可下调大鼠神经肌肉接头处突触后膜乙酰胆碱受体表达,但并不改变运动神经轴突末梢与骨骼肌纤维的接触面积.     

切口痛-瑞芬太尼痛觉过敏大鼠脊髓背角含GluR1和GluR2亚基AMPA受体表达的变化

目的 探讨切口痛-瑞芬太尼痛觉过敏大鼠脊髓背角含GluR1和GluR2亚基AMPA受体表达的变化.方法 雄性SD大鼠32只,体重240 ～ 260 g,2～3月龄,采用随机数字表法,将其分为4组(n=8):对照组(C组)、瑞芬太尼组(R组)、切口痛组(P组)和瑞芬太尼+切口痛组(R+I组).制备足底切口痛模型的同时开始静脉输注瑞芬太尼1.0 μg·kg-1·min-1,输注1h.分别瑞芬太尼输注前、输注停止后2、6、24和48 h时测定机械刺激缩足阈(PWT)和热刺激缩足潜伏期(PWL).最后一次行为学测试后处死大鼠,取脊髓背角L4-6节段,采用Western blot法测定总蛋白及膜蛋白AMPA受体GluR1和GluR2亚基表达,并计算膜蛋白二者表达的比值(GluR1/GluR2).结果 与C组比较,I组、R组和R+I组PWL缩短,PWT降低,总蛋白及膜蛋白GluR1表达上调,总蛋白及膜蛋白GluR2表达下调,膜蛋白GluR1/GluR2增加(P＜0.05).与R组和I组比较,R+I组PWL缩短,PWT降低,总蛋白及膜蛋白GluR1表达上调,总蛋白及膜蛋白GluR2表达下调,膜蛋白GluR1/GluR2增加(P＜0.01).结论 大鼠切口痛-瑞芬太尼痛觉过敏的形成与脊髓背角总蛋白及膜蛋白含GluR1亚基AMPA受体表达上调和含GluR2亚基AMPA受体表达下调,导致膜蛋白含GluR1亚基AMPA受体组成比例增加有关.     

重症肌无力血清抗乙酰胆碱受体抗体和抗突触前膜抗体监测的临床意义

用ＡＢＣ－ＥＬＩＳＡ法对５０例重症肌无力（ＭＧ）病人血清中抗乙酰胆碱受体抗体（ＡｃｈＲａｂ）和抗突触前膜抗体（ＰｒＭａｂ）进行检测。结果发现：①ＭＧ患者抗体总阳性３７例（阳性率７４％），其中ＡｃｈＲａｂ阳性３３例（６６％），ＰｒＭａｂ２９例（５８％），二者均显示重症患者阳性率高于轻症。②血清中两种抗体滴度重症患者均明显高于轻症，胸腺肿瘤ＡｃｈＲａｂ滴度明显高于胸腺增生病例，抗体滴度与胸腺病理关系呈肿瘤＞萎缩或正常＞增生。③ＡｃｈＲａｂ和ＰｒＭａｂ高度相关。结果表明ＡｃｈＲａｂ与ＭＧ病情轻重和胸腺病理有一定关系，可用于ＭＧ的病情监测，ＰｒＭａｂ同样可以作为ＭＧ的一项免疫学诊断指标，有重要的临床应用价值。     

AMPA谷氨酸受体亚基-2在大鼠脊髓损伤急性期对少突胶质前体细胞凋亡的影响

目的:探讨AMPA谷氨酸受体亚基-2 (AMPA-GluR2)在大鼠脊髓损伤急性期对少突胶质前体细胞(oligodendrocyte precursor cells,OPCs)凋亡的影响。方法:60只SD雌性大鼠随机分为假手术组(Sham组,n=15),脊髓损伤组(SCI组,n=15),AMPA受体拮抗剂NBQX组(n=15)和Ca2+通透性AMPA受体拮抗剂JSTx组(n=15)。SCI组、NBQX组和JSTx组应用Allen′s打击法建立大鼠脊髓(T9)损伤模型。采用BBB评分评估各组大鼠脊髓损伤后运动功能恢复情况。HE染色观察脊髓损伤后病理学改变。免疫组化和免疫蛋白印迹(Western blot)法检测AMPA-GluR2在各组大鼠脊髓组织中的表达情况。免疫荧光标记OPCs并应用TUNEL法检测其在各组中的凋亡情况。结果:SCI组BBB评分较假手术组降低(P0.05),脊髓损伤后3d NBQX组(3.60±0.65)和JSTx组(3.80±0.76)BBB评分较SCI组(1.50±0.35)高(P0.05),NBQX组和JSTx组之间无差异(P0.05)。HE染色结果显示SCI组和两个拮抗剂组的脊髓组织均存在损伤,脊髓组织腹侧和腹外侧白质病理学损伤评分显示NBQX组(1.60±0.42)与JSTx组(1.50±0.35)评分较SCI组(2.30±0.20)低(P0.05)。AMPA-GluR2免疫组化结果显示,脊髓损伤后3d SCI组阳性细胞数(6.15±0.52)较假手术组(13.25±0.21)明显减少(P0.05),NBQX组(2.10±0.42)和JSTx组(4.45±0.54)阳性细胞数较SCI组少(P0.05),NBQX组阳性细胞数最少,与JSTx组比较有显著性差异(P0.05)。Western blot结果显示,脊髓损伤后3d SCI组和两个拮抗剂组AMPA-GluR2表达水平均较假手术组(0.94±0.07)降低(P0.05),NBQX组(0.37±0.07)及JSTx组(0.54±0.12)较SCI组(0.69±0.03)低(P0.05),且NBQX组AMPA-GluR2表达水平最低(P0.05)。免疫荧光显示,脊髓损伤后3d各组大鼠脊髓组织均存在免疫荧光标记的OPCs;TUNEL法检测OPCs凋亡指数表明,NBQX组(0.21±0.02)和JSTx组(0.17±0.01)较SCI组(0.42±0.02)均降低(P0.05),且JSTx组较NBQX组降低(P0.05)。结论:大鼠脊髓损伤急性期OPCs凋亡与脊髓组织中AMPA-GluR2表达下降有关。     

海马AMPA受体在氯胺酮对大鼠抗抑郁效应中的作用

目的 评价海马α-氨基-3-羟基-5-甲基-4-异恶唑基丙酸(AMPA)受体在氯胺酮对大鼠抗抑郁效应中的作用.方法 雄性Wistar大鼠30只,2月龄,体重180～220 g,采用随机数字表法,将其随机均分为3组(n=10):对照组(C组)、氯胺酮组(K组)和AMPA受体拮抗剂NBQX组(N组).行强迫游泳实验15 min建立大鼠抑郁模型.于第2天N组腹腔注射NBQX 10 mg/kg;30 min后C组腹腔注射生理盐水1.0ml,K组和N组腹腔注射氯胺酮10 mg/kg.30 min后再次进行强迫游泳试验5 min,记录大鼠不动时间.然后处死大鼠,取海马组织,测定磷酸化雷帕霉素靶蛋白(p-mTOR)和磷酸化谷氨酸受体1( p-GluRl)的表达.结果 与C组比较,K组不动时间缩短,海马mTOR和GluR1表达上调,N组不动时间缩短,海马mTOR表达上调,GluR1表达下调(P＜0.05);与K组比较,N组不动时间延长,海马mTOR和GluR1表达下调(P＜0.05).结论 海马AMPA受体参与了氯胺酮对大鼠的抗抑郁作用,可能与抑制mTOR和GluR1的活性有关.     

Novel targets in pain research: The case for CB2 receptors as a biorational pain target

The prevalence of neuropathic pain is rising, and is expected to further increase in aging populations. However, drug treatment for neuropathic pain remains inadequate, with the best available treatments having limited efficacy and dose-limiting side effects. Cannabinoids have been shown in clinical trials to be moderately effective at reducing neuropathic pain, but doses of cannabinoids currently in use are severely curtailed by psychoactive side effects through actions on the cannabinoid CB1 receptor. A relatively new class of drugs, selective cannabinoid CB2 receptor agonists, have shown considerable efficacy in a variety of animal models of neuropathic pain. Importantly, these drugs lack the psychoactivity of non-selective cannabinoid receptor agonists. The mechanisms by which CB2 receptor agonists reduce neuropathic pain are under intense investigation, and there are a number of plausible mechanisms by which CB2 agonists have antinociceptive effects. In this article, we review the preclinical evidence for the efficacy of CB2 agonists in the treatment of neuropathic pain. We also review the state of clinical development and trial of CB2 agonists, and argue that the need to test CB2 agonists for neuropathic pain in humans is urgent.     

Interaction between a NMDA receptor antagonist, AP-5 and an AMPA receptor antagonist, YM 872 in antinociception in the spinal cord

Background: The intrathecal N -methyl- d -aspartate (NMDA) receptor antagonist, AP-5 and the α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor antagonist, YM 872 showed inhibition on both acute and facilitated nociception in our previous study. The present study was performed to investigate the interaction between intrathecal AP-5 and YM 872 in antinociception for acute and chronic nociception.
Methods: Sprague–Dawley rats with lumbar intrathecal catheters were tested for their thermal tail withdrawal response and for their paw flinches by formalin injection after intrathecal administration of AP-5 or YM 872. The effects of the combination were tested by an isobolographic analysis using 50% effective dose (ED50). Total fractional dose was calculated as (ED50 dose of AP-5 in combination)/(ED50 dose of AP-5 alone)+(ED50 dose of YM 872 in combination)/(ED50 dose of YM 872 alone).
Results: Intrathecally administered AP-5, YM 872, and their combination produced dose-dependent increases of the tail-flick latency and decreases in the number of flinches in both phase 1 and 2 of the formalin test. The ED50 values of the combination were significantly lower than the calculated additive values ( P <0.01). Total fractional dose value was 0.22 in the tail flick test, 0.12 in the phase 1 and 0.14 in the phase 2 of the formalin test.
Conclusion: An NMDA receptor antagonist, AP-5 and an AMPA receptor antagonist, YM 872 had synergistic antinociceptive effects on both acute thermal and inflammatory induced acute and facilitated nociception.     

黑皮质素受体在神经病理性疼痛中的介导作用

国际疼痛研究会将神经病理性疼痛定义为:“原发或原发病灶引发的或神经系统的功能障碍所引起的疼痛”[1]。神经系统内的损伤或功能障碍,被认为是外周神经病理性疼痛或中枢性疼痛的主要病因。Dvorkin[2]认为神经病理性疼痛即是通常所指的慢性疼痛,即持续超过3个月或在疾病治愈后持续时间超出正常范围的疼痛。感染、创伤、机体代谢性疾病、恶性肿瘤的化疗、外科手术、射线、神经毒性药物、神经受压、炎症和肿瘤的侵袭都可以引起外周神经病理性疼痛和中枢神经病理性疼痛。神经病理性疼痛的发病率近年来有逐渐增加的趋势。原因主要在于以下几方…     

AMPA receptors: New targets for psychiatric disorders

AMPA receptors are one of the major excitatory receptors within the CNS with many of their functional effects being mediated by alterations in their trafficking to the cell surface and targeting into the synapse. Integral to these functions, and consequently, AMPA receptor activity is a class of proteins termed transmembrane AMPA receptor regulatory proteins (TARPs) which also possess diverse effects on AMPA receptor pharmacology. Incredibly, despite the evident importance of TARPs in AMPA receptor function, very few studies even allude to the potential significance of their potential role within the glutamatergic pathology of neurological disorder. This review brushes upon the importance of these proteins as potential targets for therapeutic agents in several psychological disorders where an increasingly significant glutamatergic component is being recognised with a rapidly expanding range of AMPA receptor modulatory compounds – AMPAkines – potentially offering new pharmacological intervention for disorders originally treated by targeting other neurotransmitter systems.