谷氨酸对丘脑束旁核痛兴奋神经元放电的影响

目的：观察脑室注射谷氨酸（Glu)对大鼠丘脑束旁核（PF）痛兴奋神经元（PEN）电变化的影响。方法：以电脉冲刺激右侧坐骨神经作为伤害性痛刺激，用玻璃微电极细胞外记录神经元放电的变化。结果：（1）伤害性刺激使大鼠丘脑PF的PEN诱发放电频率增加；（2）脑室注射Glu(1.5μg/10μl）加强PEN的电活动，使PEN放电频率的净增值增加，潜伏期缩短；（3）这种作用可被Glu的NMDA受体拮抗剂MK－801（0．17μg/0.5μl)所阻断。结论：Glu在中枢痛沉调制中可能起兴奋作用，而NMDA受体参与介导中枢伤害性信息的传递过程。     

大鼠脑室注射强啡肽A（1～13）在冷水甩尾测痛中的镇痛及抗吗 …

建立大鼠冷水甩尾模型，观察脑室注射（ｉ．ｃ．ｖ．）强啡肽Ａ（１～１３）的镇痛作用及其对吗啡镇痛作用的影响。用冷水甩尾测痛观察皮下注射（ｓ．ｃ．）吗啡镇痛作用的时效和量效曲线以验证该测痛模型的可行性，强啡肽Ａ（１～１３）是脑室注射给药，冷水甩尾测痛模型稳定性好，灵敏度和准确度高，用冷水甩尾测痛时ｉ．ｃ．ｖ强啡肽Ａ（１－１３）有明显的镇痛作用，并可剂量依赖地对抗ｓ．ｃ．吗啡的镇痛作用，冷水甩尾测痛能效     

谷氨酸对抗吗啡对丘脑束旁核痛反应神经元放电的影响

目的 研究脑室注射谷氨酸(Glu)对吗啡引起的大鼠两侧丘脑束旁核痛反应神经元电活动的影响。方法 以电脉冲刺激右侧坐骨神经作为伤害性刺激，同时用两根玻璃微电极细胞外记录两侧丘脑束旁核神经元的放电。结果 (1)腹腔注射吗啡(10mg／kg)可抑制痛兴奋神经元(PEN)和加强痛抑制神经元(PIN)的电活动；(2)脑室注射Glu(1．5μg／10μl)能对抗吗啡引起PEN放电的抑制作用和PIN电活动的加强作用；(3)Glu可同时对抗吗啡所引起束旁核中PEN和PIN的电变化。结论 Glu对吗啡引起的镇痛效应有明显的对抗作用，提示Glu在中枢伤害性信息整合方面发挥重要作用。     

NMDA受体拮抗剂MK—801阻断福尔马林诱导的大鼠脊髓c—Fos表达

大量证据表明，兴奋性氨基酸（ｅｘｃｉｔａｔｏｒｙａｍｉｎｏａｃｉｄｓ，ＥＡＡｓ）是脊椎动物中枢神经系统的兴奋神经递质，并参与伤害性信息的一级传递，但对ＮＭＤＡ受体在不同伤害性信息传递中的作用却颇有争议，本实验采用免疫组化方法显示脊髓Ｆｏｓ样免疫活性（Ｆｏｓ－ｌｉｋｅｉｍｍｕｎｏｒｅａｃｔｉｖｉｉｔｙ，ＥＬＩ）神经元，观察化学性伤害性刺激物福尔马林（５％，１５０μｌ）足底注射对脊髓ｃ－Ｆｏｓ表达的诱     

神经生长因子对大鼠脑缺血后海马CA1区神经细胞凋亡的影响

目的　研究神经生长因子（ Ｎ Ｇ Ｆ）在缺血性脑损伤中对神经细胞凋亡的影响。方法　采用大鼠 ４ 血管闭塞脑缺血模型， Ｔ Ｕ Ｎ Ｅ Ｌ 方法原位标记 Ｄ Ｎ Ａ 片段，观察脑室内注射 Ｎ Ｇ Ｆ 后海马 Ｃ Ａ１ 区神经细胞凋亡的变化。结果　使用 Ｎ Ｇ Ｆ 后 ３ｄ 海马 Ｃ Ａ１ 区 Ｔ Ｕ Ｎ Ｅ Ｌ 阳性神经细胞数为神经细胞总数的１３．９％ ±１１．６％ ，与缺血对照组（２１．３％ ±１３．７％ ）比较显著减少（ Ｐ＜ ０．０１）。结论　外源性 Ｎ Ｇ Ｆ 对脑缺血所致的神经细胞凋亡可能具有一定的保护作用。     

大鼠脑室注射强啡肽A(1～13)在冷水甩尾测痛中的镇痛及抗吗啡镇痛作用

建立大鼠冷水甩尾模型,观察脑室注射（ｉ．ｃ．ｖ．）强啡肽Ａ（１～１３）的镇痛作用及其对吗啡镇痛作用的影响。用冷水甩尾测痛观察皮下注射（ｓ．ｃ．）吗啡镇痛作用的时效和量效曲线以验证该测痛模型的可行性;强啡肽Ａ（１～１３）经侧脑室注射给药。冷水甩尾测痛模型稳定性好,灵敏度和准确度高;用冷水甩尾测痛时ｉ．ｃ．ｖ．强啡肽Ａ（１～１３）有明显的镇痛作用,并可剂量依赖地对抗ｓ．ｃ．吗啡的镇痛作用。冷水甩尾测痛能有效检测ｓ．ｃ．吗啡和ｉ．ｃ．ｖ．强啡肽的镇痛作用;大鼠ｉ．ｃ．ｖ．强啡肽Ａ（１～１３）可对抗ｓ．ｃ．吗啡的镇痛作用。     

颈动脉注射辣椒素激活脑干心血管相关核团的儿茶酚胺神经元

在外周压力感受器去神经支配的大鼠上，用Ｆos蛋白和酪氨酸羟化酶（ＴＨ）的双重免疫组化方法，研究辣椒素的效应是否通过激活脑干核团内儿茶酚胺能神经元而诱发。结果显示，颈动脉注射辣椒素诱发脑干中最后区（ＡＰ）、孤束核（ＮＴＳ）、巨细胞旁外侧核（ＰＧＬ）和蓝斑（ＬＣ）等多个部位出现大量ＦOS样免疫反应（ＦＬＩ）神经元和双标神经元，辣椒素受体阻断剂钌红（ＲＲ）或ＮＭＤＡ受体阻断剂ＭＫ－８０１可明显减弱此效应。以上结果表明，辣椒素的兴奋效应通过激活儿茶酚胺能神经元而诱发，辣椒素受体和／（或）谷氨酸介导这一效应。     

生长抑素调节疑核神经元兴奋性氨基酸受体介导的兴奋

在含有孤束核中央亚核（ＮＴＳｃ）疑核神经元密集区（ＡＭＢｃ）及孤束─疑核传导束的脑片，注射生长抑素（ＳＳＴ）于ＡＭＢｃ区，对Ｎ—ｍｅｔｈｙｌ—Ｄ－ａｓｐａｒｔａｔｅ（ＮＭＤＡ）引起的疑核神经元膜电位去极化有易化作用，而注射ｃｙｓｔｅａｍｉｎｅ耗竭内源性ＳＳＴ后，ＮＭＤＡ的去极化作用减弱；ＮＭＤＡ受体阻断剂Ｄ，Ｌ—２—ａｍｉｎｏ—７一ｐｂｏｓｐｈｏ－ｎｏｈｅｐｔａｎｏｉｃａｃｉｄ（ＡＰ─７）使疑核神经元兴奋性突触后电位（ＥＰＳＰ）幅度降低，而ＳＳＴ可翻转ＡＰ—７的抑制效应；对ｎｏｎ—ＮＭＤＡ介导的疑核神经元膜去极化，ｃｙｓｔｅａｍｉｎｅ亦对其有明显抑制作用；甘氨酸（ｇｌｙｃｉｎｅ）可阻断ＳＳＴ易化疑核神经元的去极化作用。这些结果表明，ＳＳＴ对疑核神经元兴富性氨基酸（ＥＡＡ）受体介导的兴奋起重要的调节作用。     

中脑导水管周围灰质和海马在ACTH镇痛中的相互关系

以往工作发现，中脑导水管周围灰质（ＰＡＧ）和海马在非阿片肽ＡＣＴＨ痛觉调制中占有重要地位。但它们之间的相互影响在ＡＣＴＨ痛觉调制中的作用，尚未阐明。本工作利用免疫组织化学和病阈测定方法，进一步观察大鼠ＰＡＧ和海马在ＡＣＴＨ镇痛时的相互关系，并与吗啡镇痛作用相比较。结果如下：（１）海马内注射ＡＣＩＨ（０．５ｕ／４μｌ）或吗啡（５μｇ／４μｌ），痛阈明显升高（１１９．３±４．７％，１２２．７±２６．８％）与对照组比较有显著差异（Ｐ＜０．０１），该明显效应均可被ＰＡＧ内注射阿片受体拮抗剂纳络酮所阻断；（２）ＰＡＧ内注射吗啡或ＡＣＴＨ后病阈提高更显著（１８０．９±５０．３％，２１９．８±７７．０％，Ｐ＜０．０１），但海马内注射纳络酮可阻断前者的效应（Ｐ＜０．０５）而对后者却无影响（Ｐ＞０．０５）；（３）伤害性刺激福尔马林（Ｆ）可诱发大鼠脊髓腰膨大背角原癌基因ｃ－ｆｏｓ显著表达，以Ⅰ、Ⅱ层较显著，海马或ＰＡＧ内注射ＡＣＴＨ均可抑制其背角ｃ－ｆｏｓ表达。结果提示：ＰＡＧ、海马均参与ＡＣＴＨ和阿片系统对脊髓痛信息传递的调制作用，在ＡＣＴＨ痛觉调制作用中，表明ＰＡＧ、海马之间的相互影响是复杂的。     

κ阿片受体激动剂抑制大鼠吗啡戒断症状的发生

用多次注射吗啡的方法造成大鼠对吗啡的依赖，给大鼠脊髓蛛网下腔（ｉ．ｔ．）注射κ（ｋａｐｐａ）阿片受体激动剂Ｕ－５０，４８８Ｈ（２．５，５，１０μｌ）或κ受体拮抗剂ｎｏｒ－ＢＮＩ（１．２５，２．５，５μｌ／１０μｌ）后，用纳洛酮（ＮＸ）催瘾，观察并记录四种戒断症状；湿科（ｗｅｔｓｈａｋｅｓ）咬牙（ｔｅｅｔｈｃｈａｔｔｅｒｉｎｇ）逃跑企图（ｅｓｃａｐｅａｔｔｅｍｐｔｓ），体重丢失（ｗｅｉｇｈｔｌｏｓｅ     

听源性惊厥增强大鼠星形胶质细胞Cx43基因表达

星形胶质细胞之间通过缝隙连接形成偶联，其缝隙连接蛋白为Cx43。该缝隙连接对神经元兴奋时释放到细胞外的K＋起空间缓冲作用。本研究以遗传性癫痫易感大鼠P77PMC为模型，采用原位杂交的方法，观察了一次听源性惊厥后脑内星形胶质细胞Cx43基因表达的变化，结果显示，P77PMC大鼠一次听源性惊厥后在大脑皮质、海马Cx43mRNA表达呈时间依赖性增加，从惊厥后2h开始增加，4～8h达高峰，24h仍高于对照。结果表明：惊厥时，皮质和海马星形胶质细胞Cx43基因表达增强，可能有利于星形胶质细胞对神经元兴奋时释放到细胞外的K＋产生空间缓冲作用，以便维持神经辕围的的K＋平衡。     

胞内乳酸对急性分离大鼠新皮层神经元KATP通道的影响

采用膜片钳技术内面向外式记录法，研究了胞内乳酸对急性分离大鼠皮层神经元上ＡＴＰ敏感钾通道（ＫＡＴＰ通道）的影响。结果显示：浴槽液中加入５～２０ ｍ ｍ ｏｌ／Ｌ乳酸，通道电流幅度增大，电导由（２０２±１１）ｐＳ增到大（２５３±１３）ｐＳ；乳酸浓度＞ ２０ ｍ ｍ ｏｌ／Ｌ时，部分通道出现多级开放。当膜超极化时，乳酸可增加通道平均开放时间及开放概率并随其浓度的增大而增加。浴槽液中乳酸浓度为２０ ｍ ｍ ｏｌ／Ｌ时，ＡＴＰ阻断通道电流活动的半数有效浓度（ＩＣ５０）为１ ｍ ｍ ｏｌ／Ｌ，较无乳酸时ＩＣ５０（０．０５ ｍ ｍ ｏｌ／Ｌ）明显增高，即通道对ＡＴＰ敏感性明显降低（Ｐ＜ ０．０１）。上述结果表明：胞内乳酸可通过增大电导、增加开放概率、诱导多通道开放及降低通道的ＡＴＰ敏感性参与调节皮层神经元上ＫＡＴＰ通道。提示：脑在缺氧情况下，胞内无氧代谢所产生的乳酸可先于ＡＴＰ耗竭激活ＫＡＴＰ通道，降低神经元兴奋性，从而起到保护作用。     

雌激素对小鼠下丘脑腹内侧核神经元多聚核糖体的影响

电镜观测苯丙酸雌二醇（ＥＢ）和乙酸孕酮（ＨＰＣ）对雌性小鼠下丘脑腹内侧核神经元多聚核糖体的影响。根据雌鼠的动惰周期，对切除卵巢的幼鼠（ＯＶＸ）每５天分别肌肉注射１次８μｇＥＢ、２ｍｇＨＰＣ或８μｇＥＢ加２ｍｇＨＰＣ。疗程２个月。结果显示：（１）神经元胞质中游离型多聚核糖体每μｍ２的含量在ＯＶＸ组与正常组（ＩＮＴ）、ＯＶＸ＋ＥＢ组、ＯＶＸ＋ＨＰＣ组和ＯＶＸ＋ＥＢ、ＨＰＣ组比较均无显著差异（Ｐ＞０．０５）。（２）附着粗面内质网膜表面的结台型多聚核糖体每μｍ含量在ＯＶＸ组分别比ＩＮＴ组、ＯＶＸ＋ＥＢ组、ＯＶＸ＋ＨＰＣ组和ＯＶＸ＋ＥＢ．ＨＰＣ组少２９．８％、２６．２％、３５．２％和３３．７％，均有非常显著差异（Ｐ＜０．００５）。本实验结果证实雌性激素特别是孕酮在小鼠生育早期使下丘脑腹内侧核神经元结合型多聚核糖体含量增多。     

阿片肽促进大鼠大脑皮层神经细胞谷氨酸释放、摄取及细胞内游离钙浓度增加

本文以大鼠大脑皮层神经细胞为研究对象，探讨阿片肽β─内啡肽和亮脑啡肽对神经细胞的作用及其与谷氨酸释放、摄取和细胞内游离钙浓度的变化关系。结果表明：β─内啡肽及亮脑啡肽能促进大鼠大脑皮层神经细胞谷氨酸的释放、摄取和细胞内游离钙浓度增加。提示外源性阿片肽对神经细胞具有兴奋性作用，在惊厥性疾病的发生、发展过程中可能起着一定的作用。     

Spinal nerve ligation decreases γ-aminobutyric acidB receptors on specific populations of immunohistochemically identified neurons in L5 dorsal root ganglion of the rat

This study examined the distribution of γ‐aminobutyric acid (GABA)_B receptors on immunohistochemically identified neurons, and levels of GABA_B(1) and GABA_B(2) mRNA, in the L4 and L5 dorsal root ganglia (DRG) of the rat in the absence of injury and 2 weeks after L5 spinal nerve ligation. In uninjured DRG, GABA_B(1) immunoreactivity colocalized exclusively with the neuronal marker (NeuN) and did not colocalize with the satellite cell marker S‐100. The GABA_B(1) subunit colocalized to >97% of DRG neurons immunoreactive (IR) for neurofilament 200 (N52) or calcitonin gene‐related peptide (CGRP), or labeled by isolectin B4 (IB4). Immunoreactivity for GABA_B(2) was not detectable. L5 spinal nerve ligation did not alter the number of GABA_B(1)‐IR neurons or its colocalization pattern in the L4 DRG. However, ligation reduced the number of GABA_B(1)‐IR neurons in the L5 DRG by ≈38% compared with sham‐operated and naïve rats. Specifically, ligation decreased the number of CGRP‐IR neurons in the L5 DRG by 75%, but did not decrease the percent colocalization of GABA_B(1) in those that remained. In the few IB4‐positive neurons that remained in the L5 DRG, colocalization of GABA_B(1)‐IR decreased to 75%. Ligation also decreased levels of GABA_B(1) and GABA_B(2) mRNA in the L5, but not the L4 DRG compared with sham‐operated or naïve rats. These findings indicate that the GABA_B receptor is positioned to presynaptically modulate afferent transmission by myelinated, unmyelinated, and peptidergic afferents in the dorsal horn. Loss of GABA_B receptors on primary afferent neurons may contribute to the development of mechanical allodynia after L5 spinal nerve ligation. J. Comp. Neurol. 520:1663–1677, 2012. © 2011 Wiley Periodicals, Inc.     

Dorsal Root Ganglia Macrophages Maintain Osteoarthritis Pain

Pain is the major debilitating symptom of osteoarthritis (OA), which is difficult to treat. In OA patients joint tissue damage only poorly associates with pain, indicating other mechanisms contribute to OA pain. Immune cells regulate the sensory system, but little is known about the involvement of immune cells in OA pain. Here, we report that macrophages accumulate in the dorsal root ganglia (DRG) distant from the site of injury in two rodent models of OA. DRG macrophages acquired an M1-like phenotype, and depletion of DRG macrophages resolved OA pain in male and female mice. Sensory neurons innervating the damaged knee joint shape DRG macrophages into an M1-like phenotype. Persisting OA pain, accumulation of DRG macrophages, and programming of DRG macrophages into an M1-like phenotype were independent of Na_v1.8 nociceptors. Inhibition of M1-like macrophages in the DRG by intrathecal injection of an IL4-IL10 fusion protein or M2-like macrophages resolved persistent OA pain. In conclusion, these findings reveal a crucial role for macrophages in maintaining OA pain independent of the joint damage and suggest a new direction to treat OA pain.SIGNIFICANCE STATEMENT In OA patients pain poorly correlates with joint tissue changes indicating mechanisms other than only tissue damage that cause pain in OA. We identified that DRG containing the somata of sensory neurons innervating the damaged knee are infiltrated with macrophages that are shaped into an M1-like phenotype by sensory neurons. We show that these DRG macrophages actively maintain OA pain remotely and independent of joint damage. The phenotype of these macrophages is crucial for a pain-promoting role. Targeting the phenotype of DRG macrophages with either M2-like macrophages or a cytokine fusion protein that skews macrophages into an M2-like phenotype resolves OA pain. Our work reveals a mechanism that contributes to the maintenance of OA pain distant from the affected knee joint and suggests that dorsal root ganglia macrophages are a target to treat osteoarthritis chronic pain.     

PAIN-RELIEVING EFFECTS OF ACUPUNCTURE AND ELECTROACUPUNCTURE IN AN ANIMAL MODEL OF ARTHRITIC PAIN

The effects of acupuncture and electroacupuncture on an animal model of arthritic pain were examined. Under halothane anesthesia, arthritic pain was induced by the injection of carrageenan into the knee joint cavity of male Sprague-Dawley rats. Behavioral performance was tested before and after the termination of acupuncture or electroacupuncture. Electrophysiologically, the responses of afferents to a movement cycle were recorded before and after acupuncture or electroacupuncture. After the acupuncture procedure, the weight-bearing force of the rats was significantly improved and the neural responses to noxious movement stimulation were reduced. Electroacupuncture significantly improved weight-bearing behavior and inhibited neural responses of articular afferents to noxious stimulation. These results indicate that acupuncture and electroacupuncture may provide a potent strategy in relieving arthritic pain.     

Antinociception induced by local injections of carbachol into the nucleus raphe magnus in rats: Alteration by intrathecal injection of monoaminergic antagonists

Electrical stimulation of neurons located in the nucleus raphe magnus (NRM) produces antinociception which appears to result from inhibition of spinothalamic tract neurons located in the spinal cord dorsal horn. Iontophoretic application of acetylcholine also activates NRM neurons and microinjection of cholinergic agonists such as carbachol into the NRM produces a profound, long-lasting antinociception. Since the antinociception induced by electrical stimulation of NRM neurons is mediated, at least in part, by bulbospinal serotonergic and noradrenergic neurons, the role of these monoaminergic neurons in mediating the antinociception induced by microinjecting carbachol in the NRM was examined in the present study. To this end, various antagonists of serotonin and norepinephrine were injected into the spinal cord subarachnoid space following the induction of antinociception by the local injection of carbachol into the NRM. The serotonergic antagonist methysergide had no effect on carbachol-induced antinociception. However, the alpha 2-noradrenergic antagonist yohimbine attenuated, while the alpha 1-noradrenergic antagonists prazosin and WB4101 increased the effects of carbachol. The non-selective noradrenergic antagonist phentolamine also attenuated the effects of carbachol. These results lead to the suggestion that the antinociception induced by the local injection of carbachol into the NRM is mediated by selective activation of bulbospinal noradrenergic neurons. Furthermore, the antinociception resulting from the activation of these descending noradrenergic neurons appears to be mediated by alpha 2-noradrenergic receptors located in the spinal cord dorsal horn. Finally, the local injection of carbachol into the NRM also appears to activate another population of noradrenergic neurons which produces hyperalgesia mediated by alpha 1-noradrenergic receptors.     

白细胞介素2抑制脊髓痛敏神经元的活动

白细胞介素２（ＩＬ－２）是免疫系统中的一种重要的免疫调节物质。ＩＬ－２及其受体不仅存在于外周组织也分布在脑的许多部位，参与对神经系统的调节。本文旨在研究ＩＬ－２是否调制痛觉信息的传递。在猫的脊髓背角记录了１８个痛敏神经元。（１）侧脑室注射ＩＬ－２（９３０Ｕ／μｌ，２０－１００μｌ）９４．４％的神经元（ｎ＝１０）的电刺激外周神经引起的Ｃ反应受到明显的抑制，抑制时程４－２５分钟。而静脉或脊髓表面局部经药，对Ｃ反应没有明显影响。（２）记录了５个神经元对辐射热（５０℃）刺激下肢庶部诱发的反应。感受野局部注射ＩＬ－２（１０—２０μｌ），使伤害性热反应抑制了７６％，但不影响轻触感受野引起的反应。纳洛酮可反转ＩＬ－２引起的伤害性反应的抑制。本实验表明，ＩＬ－２通过感受器水平的外周机制和脑干下行抑制机制参与脊髓痛觉信息的调制。