鞘内注射GABA转运体-1抑制剂NO-711对神经病理痛大鼠脊髓Fos蛋白表达的影响

目的:观察脊髓水平GABA转运体-1(γ-aminobutyric acid transporter-1,GAT-1)抑制剂NO-711对坐骨神经慢性松结扎(chronic constriction injury,CCI)大鼠机械痛敏和热痛敏以及Fos蛋白表达的影响,探讨NO-711抗伤害性的可能机制。方法:雄性SD大鼠84只,随机分为4组(n=21):假手术生理盐水组、假手术抑制剂组、神经损伤生理盐水组和神经损伤抑制剂组。各组大鼠CCI前5 d进行鞘内置管,在术前测定基础机械性缩足反射阈值(mechanical withdrawal threshold,MWT)和热缩足潜伏期(thermal withdrawal laten-cy,TWL)及Fos蛋白的表达,CCI后5 d鞘内注射100μg NO-711或生理盐水,测定节扎前、给药前、给药后0.5,1,2,4和8 h大鼠MWL和TWL及Fos蛋白的表达。结果:与给药前和神经损伤生理盐水组相比,神经损伤抑制剂组大鼠在给药后机械痛敏和热痛敏以及Fos蛋白的表达均逐渐降低,并随时间的延长又逐渐恢复到给药前水平,在给药后1 h时作用最明显,并一直持续到给药后4 h...     

鞘内注射益赛普对神经病理性疼痛大鼠痛敏的影响

目的观察鞘内注射益赛普对神经病理性疼痛大鼠痛敏的影响。方法成年雄性SD大鼠鞘内成功置管后,随机分为3组(n=10),分别为假手术组、慢性坐骨神经损伤(CCI)组(CCI+生理盐水)和益赛普组(CCI+益赛普)。于术后30min、第2、3d予鞘内注射益赛普或生理盐水。于术前1d,术后1、3、7、10、14d测定机械性痛觉阈值(MWT)、热痛觉阈值(TWL)。结果与术前1d比较,CCI组大鼠术后的MWT和TWL均明显下降(P<0.05);益赛普组仅在术后3、7d的MWT及1、3、7、10d的TWL下降的差异有统计学意义(P<0.05)。与假手术组比较,CCI组和益赛普组(除术后14d)术后各时点MWT和TWL均明显降低(P<0.05)。与CCI组比较,益赛普组术后各时点MWT和TWL均明显升高(P<0.05)。结论鞘内注射益赛普能够抑制CCI引起的神经病理性疼痛。     

γ-氨基丁酸转运体抑制剂NO-711术前鞘内注射对坐骨神经慢性挤压伤大鼠神经病理性痛觉过敏的影响

γ-氨基丁酸是哺乳动物中枢神经系统主要的抑制性神经递质。近年来的研究发现GABA递质受体系统在伤害性信息传递和调节方面起着重要的作用。定位在突触前膜和神经胶质细胞的转运体GAT1是最重要的神经递质转运体之一，能快速摄取GABA从而终止其抑制作用。GABA转运体抑制剂已经被广泛用于癫痫研究，但是这种药是否对疼痛动物或人有镇痛作用仍然不是十分清楚。本实验目的是在大鼠神经病理痛模型建立前鞘内给予NO-711，观察其对大鼠热痛敏和触诱发痛的影响。     

鞘内注射吗啡对切口痛大鼠脊髓兴奋性氨基酸含量的影响

目的　研究在大鼠切口疼痛模型上鞘内注射吗啡对脊髓 (L4～ 5)兴奋性氨基酸 (天门冬氨酸和谷氨酸 )含量的影响。方法　雄性SD大鼠 32只 ,随机分为 4组 ,每组 8只。组Ⅰ为假手术组 ;组Ⅱ术前 30min鞘内注射人工脑脊液 (ACSF) 2 0 μl;组Ⅲ和组Ⅳ分别在术后 30min和术前 30min鞘内注射吗啡 10 μg。按Brennan法制成大鼠足底切口疼痛模型 ,以累计疼痛评分确定疼痛行为。应用邻苯二甲醛柱前衍生高效液相色谱法测定脊髓兴奋性氨基酸含量。结果　组Ⅱ累计疼痛评分 (17± 3)明显高于组Ⅰ (P <0 0 1) ,与组Ⅱ比较 ,组Ⅲ和组Ⅳ累计疼痛评分 (组Ⅲ :3± 2 ,组Ⅳ :2 5± 2 )明显降低 (P <0 0 1)。与组Ⅰ (天门冬氨酸 :1 90±0 2 8μmol/g ,谷氨酸 :3 9± 0 5 1μmol/g)比较 ,组Ⅱ的脊髓天门冬氨酸 (2 36± 0 39μmol/g)和谷氨酸 (4 8±0 89μmol/g)的含量明显升高 ;组Ⅲ和组Ⅳ的脊髓天门冬氨酸含量分别为 2 0 0± 0 34μmol/g和 2 0 2± 0 2 9μmol/g ,均明显低于组Ⅱ (P <0 0 5 ) ;组Ⅲ和组Ⅳ的脊髓谷氨酸含量分别为 3 9± 0 5 9μmol/g和 4 0± 0 5 6μmol/g ,也明显低于组Ⅱ (P <0 0 5 )。而两用药组上述指标比较以及用药组与组Ⅰ比较均无显著差异 (P >0 0 5 )。结论　在大鼠切口疼痛模型中     

鞘内注射可乐定对甲醛致痛大鼠脊髓c-fos表达的影响

<正>本研究通过对甲醛致痛大鼠蛛网膜下腔给予可乐定,观察大鼠伤害性行为学反应、脊髓背角Fos蛋白表达的改变,旨在探讨可乐定在甲醛致痛模型中的作用及可能的作用机制。1材料与方法     

脑室注射生长抑素或GABA对大鼠痛阈和脑内GABA或生长抑素含量的影响(英文)

目的:研究脑内Som和GABA的相互影响及其与痛觉调制的关系.方法:应用放射免疫,氨基酸分析仪和痛阈测定法.结果:发现Som 10 μg icv可使大鼠海马,脑干内GABA含量显著减少,分别由对照组的2.3±0.3和2.2±0.4 μmol g~(-1)降至1.6±0.4和1.5±0.2μmol g~(-1),痛阈由对照组的4.2±0.2 s升高到7.0±1.1 s;半胱胺600 μg icv降低脑内Som后,海马和脑干内GABA含量也明显减少,但痛阈不变.GABA 1500 μg icv后,痛阈变化不明显,而海马、脑干内Som含量均显著减少,分别由对照组的55±4和84 4 ng g~(-1)降至37±5和55±6 ng g~(-1)这一效应可被荷包牡丹碱10 μg阻断;以异烟肼300 mg kg~(-1)降低脑内GABA后,海马和脑干内Som含量即明显增多.结论:脑内Som和GABA之间存在着相互抑制作用,但与它们在痛觉调制中的作用无关.     

鞘内注射Cav3.3反义寡聚核苷酸对CCD大鼠痛阈的影响

目的观察鞘内注射Cav3.3反义寡聚核苷酸对慢性背根节压迫(chronic compression of dorsal root ganglion,CCD)大鼠痛阈的影响,探讨脊髓Cav3.3T型钙通道在神经病理痛中的作用。方法鞘内置管的雄性SD大鼠32只,随机分为4组(行为学n=8,):CCD+NS组、CCD+Cav3.3反义核苷酸组(CCD+Cav3.3-AS)、CCD+Cav3.3错义核苷酸组(CCD+Cav3.3-MM)、假手术(sham)+NS组。各组大鼠在CCD或sham后第1天开始连续4d每天两次鞘内分别注射Cav3.3-AS、Cav3.3-MM12.5μg/10μl或NS10μl,行为学部分分别观察术后1、3、5、7、10、14d大鼠机械缩足阈值(mechanica lwithdrawal threshold,MWT)和热缩足潜伏期(thermal withdrawal latency,TWL)。结果鞘内注射Cav3.3反义寡聚核苷酸能显著延缓CCD大鼠痛敏的形成,在CCD术后10d才形成与CCD+NS组类似的痛敏,而鞘内注射Cav3.3错义核苷酸则与NS组无统计学差异。结论脊髓Cav3.3参与神经病理痛的形成,抑制脊髓Cav3.3基因的表达具有疼痛治疗作用。     

鞘内注射TDAG8的siRNA对大鼠骨癌痛的缓解作用

目的观察鞘内注射T细胞死亡相关基因8(T celldeath-associated gene 8,TDAG8)的小干扰RNA(small inter-fering RNA,siRNA)对骨癌痛大鼠机械性痛觉过敏以及脊髓TDAG8表达的影响。方法通过将Walker256肿瘤细胞接种在大鼠左侧胫骨骨髓腔内建立骨癌痛模型。观察接种肿瘤前后大鼠机械缩爪反射阈值(paw withdrawl threshould,PWT)和脊髓TDAG8表达水平的变化;并进一步观察痛觉过敏形成后鞘内注射TDAG8的siRNA对大鼠PWT和脊髓TDAG8表达的影响。结果大鼠接种肿瘤后6～18 d,PWT明显下降(P<0.01),脊髓TDAG8的表达明显升高(P<0.01);与对照组相比,鞘内注射siRNA的骨癌痛大鼠,其PWT明显增高(P<0.05),脊髓TDAG8表达水平明显降低(P<0.01)。结论脊髓部位的TDAG8可能参与了大鼠骨癌痛的形成和发展,鞘内注射其siRNA可以通过干扰脊髓TDAG8的表达而具有疼痛缓解作用。     

Suppression of stretch reflex activity after spinal or systemic treatment with AMPA receptor antagonist NGX424 in rats with developed baclofen tolerance

BACKGROUND AND PURPOSE

Baclofen (a GABA_B receptor agonist) is the most commonly used anti-spasticity agent in clinical practice. While effective when administered spinally or systemically, the development of progressive tolerance represents a serious limitation for its long-term use. The goal of the present study was to characterize the treatment potency after intrathecal or systemic treatment with the selective AMPA receptor antagonist NGX424 on stretch reflex activity (SRA) and background muscle activity (BMA) in rats with developed baclofen tolerance.

EXPERIMENTAL APPROACH

Animals were exposed to 10 min of spinal ischaemia to induce an increase in BMA and SRA. Selected animals were implanted with an intrathecal PE-5 catheter and infused intrathecally with baclofen (1 µg·h⁻¹) for 14 days. Before and after baclofen infusion, changes in BMA and SRA were measured at 2 day intervals. After development of baclofen tolerance, the animals were injected intrathecally (1 µg) or subcutaneously (3, 6 or 12 mg·kg⁻¹) with NGX424, and changes in BMA and SRA were measured.

KEY RESULTS

Intrathecal or systemic delivery of NGX424 significantly suppressed the BMA and SRA in baclofen-tolerant animals. This effect was dose dependent. The magnitude of BMA and SRA suppression seen after 1 µg (intrathecal) or 12 mg·kg⁻¹ (s.c.) of NGX424 injection was similar to that seen during the first 5 days of baclofen infusion.

CONCLUSIONS AND IMPLICATIONS

These data demonstrate that the use of NGX424 can represent an effective therapy to modulate chronic spasticity in patients who are refractory or tolerant to baclofen treatment.

LINKED ARTICLE

This article is commented on by Gómez-Soriano et al., pp. 972–975 of this issue. To view this commentary visit http://dx.doi.org/10.1111/j.1476-5381.2010.00964.x     

Effects of the GABAB receptor agonist baclofen on primary drinking in rats

The effects of subcutaneous (s.c.) administration of the GABA(B) receptor agonist baclofen were investigated on primary drinking in rats. Baclofen (1-4 mg/kg) produced a dose-related reduction in cumulative water intake in 16 h water-deprived rats during the 120 min measurement period (Experiment 1). The suppressant effect of baclofen (2mg/kg) on water intake 16 h water-deprived rats was significantly attenuated by pretreatment with the GABA(B) receptor antagonist CGP 35348 (3-aminopropyl (diethoxymethyl)-phosphinic acid; 50mg/kg; s.c., Experiment 2.), indicating that the hypodipsic effects of the drug in thirsty rats are mediated by an action at GABA(B) receptors. Experiment 3 was undertaken to investigate the effects of baclofen on volemic drinking induced in rats pretreated with propylene glycol. S.C. administration of polyethylene glycol induces volemic drinking in rats by reducing extracellular fluid. Baclofen (2mg/kg, s.c.) significantly reduced the volemic drinking in rats pretreated with polyethylene glycol (30% w/v solution). Experiment 4 was conducted to investigate the effects of baclofen on osmotic drinking in non-deprived rats pretreated with hypertonic sodium chloride (NaCl) solution. Hypertonic NaCl will draw out intracellular fluid to stimulate osmotic drinking. Baclofen (2mg/kg; s.c.) significantly reduced osmotic drinking in rats pretreated with 1 ml hypertonic NaCl (16% w/v). The results of this study indicate that (i) the hypodipsic effect of baclofen in water-deprived rats is mediated by an action at GABA(B) receptors and (ii) baclofen suppresses both volemic and osmotic drinking.     

Effects of baclofen on spinal neurones of cats

Actions of baclofen, a derivative of GABA, on spinal neurones were investigated in spinal as well as in decerebrated cats. 1. Monosynaptic, polysynaptic reflexes as well as dorsal root potential V were almost completely inhibited within about 20 min and the effects persisted for more than 2 hr after application of 1.0–3.0 mg/kg. 2. Spike discharges from interneurons generated by stimulation of primary afferents were also depressed. The sensitivity of different interneurones to the drug varied. 3. Inhibitory influence from high threshold afferents upon Renshaw cells was removed by baclofen. 4. Spike numbers evoked in Renshaw cells by antidromic ventral root stimulation were unchanged after drug application. 5. Baclofen had no visible effects on the discharges of α-motoneurones elicited by stimulation of reticular formation, pyramidal tract or cuneiform nucleus. 6. It was argued from these experimental results that baclofen acts specifically on transmitter substances liberated from the primary afferent fibres.     

GABAA receptor partially mediated propofol-induced hyperalgesia at superspinal level and analgesia at spinal cord level in rats

AIM:Toobserveeffectsofpropofolonnociceptiveresponseatsuperspinalandspinallevelinrats.METHODS:Twohundredsandfifty-eightSprague-Dawleymaleratswererandomizedintothirty-twogroups.Propofolandbicucullineweremicroinjectedintolateralventricle(icv),ventrolateralperiaqueductalgray(vlPAG),intrathecal(ith),andintraperitoneal(ip).Thenoxiousresponseswereevaluatedbyhotplateandformalintest.RESULTS:Inhot-platetest,systemicandsuperspinaladministrationofpropofol(40mg·kg-1ip,100μgin10μL,icv,and4μgin…     

胍丁胺鞘内注射对骨癌痛大鼠痛行为及脊髓CXCL13表达的影响

目的 探讨胍丁胺鞘内注射对骨癌痛大鼠痛行为及脊髓趋化因子CXC配体13（CXCL13）表达的影响。方法 成年雌性SD大鼠60只,体质量200~220 g,采用随机数字表法分为3组：假手术组（A组）、骨癌痛组（B组）、骨癌痛+胍丁胺组（C组）,各20只。B、C组采用大鼠胫骨上端骨髓腔内注入Walker 256癌细胞的方法建立骨癌痛模型,A组胫骨髓腔内注射等量生理盐水,B、C两组鞘内置管。造模成功后,C组鞘内注射胍丁胺160 mg/kg,连续6天;B组鞘内给予等量生理盐水,连续6天;A组不作处理。于造模后第12天用von Frey丝测定3组大鼠机械缩足反射阈值（MWT）;痛阈测定结束后,麻醉处死大鼠,取脊髓组织,采用免疫荧光法检测CXCL13在神经元中的表达;采用Western blot法分析CXCL13蛋白表达及逆转录-聚合酶链反应（RT-PCR）法检测CXCLl3 mRNA的表达。结果 建模后12天,与A组比较,B、C组大鼠MWT明显低于A组,与B组比较,C组MWT高于B组,差异均有统计学意义（P<0.05）。建模后12天,与A组比较,B、C组大鼠CXCL13在脊髓背角神经元中表达增加,CXCL13蛋白及其mRNA表达明显增加（P<0.05）;与B组比较,C组大鼠CXCL13在脊髓背角神经元中表达降低,CXCL13蛋白及其mRNA表达明显减少（P<0.05）。结论 鞘内注射胍丁胺可有效改善大鼠骨癌痛痛觉过敏行为,其机制可能与抑制大鼠脊髓CXCL13表达有关。     

NOS抑制剂L－NAME的镇痛、致痛和致瘫作用

鞘内注射（ｉｔ）ＮＯＳ抑制剂Ｌ－ＮＡＭＥ０．１２５～４μｍｏｌ可剂量依赖性抑制大鼠足底注射Ｆｏｒｍａｌｉｎ引起的癌症反应，并有７／３１大鼠出现迟发性一过性双后肢瘫痪。ｉｔＬＮＡＭＥ５μｍｏｌ对正常大鼠无明显影响，但１０μｍｏｌ和２０μｍｏｌ均引起明显的痛敏及截瘫．ｉｔ另一ＮＯＳ抑制剂氨基胍０．２～１．０μｍｏｌ也显著抑制Ｆｏｒｍａｌｉｎ痛定反应，１．２５～７．０μｍｏｌ则引起正常大鼠剂量依赖性痛敏行为，但对后肢运动功能无影响。结果表明脊髓水平ＮＯ在痛觉传递与调制中起重要作用，过度抑制ＮＯ的产生可引起痛觉敏化和瘫痪。     

Effects of intravenously administered enantiomers of baclofen on functionally identified units in lumbar dorsal horn of the spinal cat

The present study investigated the effects of intravenous administration of the d- and l-enantiomers of baclofen on extracellular single unit spikes recorded from the lumbar dorsal horn of the spinalized cat, either anaesthetized with chloralose or decerebrated. Both enantiomers had two types of depressant effect. One was a transient (complete within 2 min), non-specific depression of the discharge of synaptically-elicited responses and of the postsynaptic glutamate-evoked excitation; it is reasoned that this effect was due to a postsynaptic action of baclofen and its antagonism by bicuculline suggests it is via classical GABA receptors. The other type of depression was more prolonged, lasting usually for more than 1 hr. It was observed as a preferential blocking of spontaneous activity, as well as of evoked responses to noxious stimuli or innocuous thermal stimuli applied to the skin, with little or no effect on responses to hair movement or to the iontophoretic application of glutamate. In addition, baclofen preferentially reduced the late, higher threshold component of evoked responses of wide dynamic range neurones to electrical stimulation of the cutaneous receptive field. Thus, whether tested on naturally- or electrically-evoked responses, baclofen had a preferential effect on those mediated by small diameter afferents. Doses giving approximately equal effects were 0.1 mg/kg for l-baclofen and 10 mg/kg for d-baclofen.The results of the present study support recent evidence of a prolonged antinociceptive effect of baelofen, indicate that at least some of this effect is mediated by an action at the spinal level and support the possibility that the action is presynaptic, perhaps on the terminals of primary afferent fibres. In addition, a similar mechanism may account for the depression of spinal polysynaptic reflexes and thus, perhaps, additionally for some of the antispastic properties of baclofen.     

鞘内西地那非能减轻神经病理性疼痛大鼠的痛觉高敏

目的观察鞘内注射西地那非对腰5(L5)脊神经切断大鼠痛觉高敏及对脊髓小胶质细胞活化、炎症细胞因子表达的影响。方法♂SD大鼠120只,随机分为5组(n=24),Ⅰ组:假手术组;Ⅱ组:L5脊神经切断模型鞘内注射生理盐水20μl;Ⅲ～Ⅴ组:L5脊神经切断模型分别鞘内注射3μg/20μl、10μg/20μl、30μg/20μl西地那非组。Ⅰ组仅暴露L5脊神经,Ⅱ～Ⅴ组均切断L5脊神经,术后d 7开始鞘内给药,Ⅰ、Ⅱ组注射20μl生理盐水,Ⅲ～Ⅴ组分别给予上述剂量西地那非,各组每天1次,连续5 d。测定各组大鼠术前1d,术后7、8、10、12 d机械痛阈(mechanical withdrawa1 thresh-old,MWT),术后8、10、12 d取L5脊髓,测定各组大鼠肿瘤坏死因子(tumor necrosis factorα,TNF-α)、白细胞介素1β(in-terleukin-1β,IL-1β)含量和小胶质细胞标记物白细胞分化抗原11b(cluster differentiation antigen 11b,CD11b)的mRNA表达水平。结果①术后7 d,与Ⅰ组相比,各组MWT明显下降(P<0.05),术后8、10、12 d与Ⅱ组相比,Ⅲ～Ⅴ剂量依赖地升高MWT(P<0.05)。②与Ⅰ组相比较,其余各组大鼠术后8、10、12 d TNF-α和IL-1β的水平及CD11b mRNA含量均明显上升(P<0.05),与Ⅱ组相比较,Ⅲ～Ⅴ于术后8、10、12 d明显剂量依赖地抑制了TNF-α和IL-1β及CD11b mR-NA的表达(P<0.05)。结论西地那非能剂量依赖性地缓解大鼠神经病理性痛觉过敏的发展,该效应可能与抑制脊髓小胶质细胞活性,减少TNF-α和IL-1β表达有关。