乙状结肠痛诱导大鼠远位触液神经元Fos蛋白的表达

目的：探讨远位触液神经元在乙状结肠痛刺激信息调控中的作用。方法：采用CB-HRP／Fos双重标记技术，观察乙状结肠痛大鼠远位触液神经元中Fos样免疫反应蛋白（Fos）表达的变化。结果：乙状结肠痛刺激后，不仅疼痛行为学评分显著增加，而且远位触液神经元内Fos表达的数量显著增加，与空白对照组相比有显著性差异。结论：远位触液神经元可能参与了机体对乙状结肠痛刺激信息传递或调控。     

“免疫-脑通讯”通路中延髓内脏带至下丘脑室旁核儿茶酚胺能作用的实验研究

背景：脂多糖(lipopolysaccharide，LPS)作为一种多克隆免疫激发剂刺激免疫细胞，来模拟免疫激发状态，观察延髓内脏带(medullary visceral zone，MVZ)投射至下丘脑室旁核(paraventricular nucleus of hypothalamus，PVN)的儿茶酚胺神经元是否对LPS刺激起反应，为脑功能保护研究提供理论依据。目的：观察MVZ投射至PVN的儿茶酚胺神经元是否对脂多糖刺激起反应，探讨MVZ至PVN的儿茶酚胺能通路在“免疫-脑通讯”中的作用。设计：以实验动物为研究对象，随机对照的研究。单位：一所军医大学的神经外科和神经科学研究所。材料：实验在南方医科大学珠江医院神经外科和解放军解放军第四军医大学全军神经科学研究所完成。10只健康清洁级成年SD大鼠由第四军医大学实验动物中心提供。方法：将WGA—HRP注人大鼠一侧PVN内，存活48h后经腹腔注射免疫刺激剂LPS诱发免疫反应，应用WGA-HRP逆行追踪与抗Fos和抗酪氨酸羟化酶(TH)抗体双重免疫组织化学相结合三重标记方法进行染色。主要观察指标：观察MVZ中WGA-HRP逆标细胞、Fos蛋白和儿茶酚胺能神经元(以TH为标记物)的分布及表达状况。结果：在MVZ内发现7种阳性神经元，即HRP，Fos和TH单标细胞，Fos／HRP，Fos／TH和HRP／TH双标细胞，Fos／HRP／TH三标细胞。Fos／HRP双标记和Fos／HRP／TH三标记细胞分别占总HRP逆行标记细胞的12．5％和39．6％。结论：MVZ对脂多糖免疫刺激起反应，并可能将免疫信息经儿茶酚胺能神经元上传至PVN；MVZ可能作为“免疫-脑通讯”的一个中继站，通过“MVZ→PVN”通路起免疫调节作用。     

雌激素对去卵巢大鼠中缝核簇5-羟色胺能神经元的影响

目的：通过观察雌二醇对去卵巢大鼠中缝核簇5-羟色胺(5-hydroxytryptamine，5-HT)免疫阳性物质表达的影响，探讨围绝经期潮热发病机制。方法：实验于2003—09／2004—01在解放军第四军医大学神经生物研究所形态学实验室完成。成年雌性SD大鼠18只，解放军第四军医大学实验动物中心提供，体质量200—250g。清洁级动物，许可证号为SCXK(军)2002—005。采用酶联免疫吸附试验测定血清激素水平，用免疫组织化学方法和图像分析技术观察大鼠中缝核簇5-HT样阳性物质的表达。结果：5-HT样阳性反应产物在大鼠中缝背核、中缝正中核表达较多，去卵巢组大鼠中缝背核、中缝正中核5-HT样阳性细胞数(82．5&;#177;17．7)及吸光度(5．12&;#177;0.46)都低于假去势组(164．1&;#177;15．4，5．90&;#177;0．51)(P&;lt;0．05)，去卵巢雌激素组大鼠中缝背核、中缝正中核5-HT样阳性神经元(149．5&;#177;13．4)及吸光度(5．80&;#177;0．41)都与假去势组类似，差异无显著性意义(P&;gt;0．05)。结论：雌激素可改变大鼠中缝背核、中缝正中核5-HT样阳性物质表达，从而影响其神经元的功能，导致绝经期潮热发生。     

异氟醚对部分脑啡肽神经元激活的作用及其机制

目的：观察异氟醚诱导大鼠中枢神经系统各核团Fos蛋白与脑啡肽的表达及共存情况。方法：SD大鼠12只，随机分为对照组和异氟醚组，每组6只。异氟醚组吸入20mL／L异氟醚2h，对照组吸入氧气。取脑和脊髓，冰冻切片，进行Fos蛋白与脑啡肽的免疫组织化学双重染色。结果：对照组中，脑啡肽免疫反应阳性(ELI)神经元较多，Fos免疫反应阳性(FLI)神经元少量、散在无规律地分布，Fos，脑啡肽双标记(FLI／ELI)神经元极少见。异氟醚组中可明显观察到ELI，FLI，FLI／ELI 3种神经元，主要分布在大脑额顶皮质、外侧隔阂、杏仁核、海马CAI区、丘脑室旁核、丘脑腹外侧核、僵核、下丘脑腹内侧核、视上核、视交叉上核、脚间核、中脑中央灰质及脊髓背角等神经核团，这些核团内FLI和ELI神经元数量与对照组比较显著增多(P&;lt;0．05或P&;lt;0．01)，在其他核团内无显著变化；Fos与脑啡肽神经元彼此靠近，分布区域非常一致，FLI／ELI神经元占FLI神经元的15％-42％。结论：异氟醚可诱导Fos蛋白在某些神经核团内表达并使其内脑啡肽增多；异氟醚可激活部分脑啡肽神经元，麻醉诱导的Fos蛋白可能作为脑啡肽基因的转录调控因子，进而引起脑啡肽的变化。     

氯胺酮对甲醛致痛诱导大鼠脊髓背角神经元兴奋性的抑制

背景：氯胺酮是否可通过影响脊髓水平的伤害性信息的传递而发挥抗伤害作用尚不清楚；一氧化氮在脊髓水平主要参与痛觉过敏的形成和发展，可诱导Fos表达，但其是否参与了氯胺酮对痛信号的转导或调控的机制不明。 目的：观察大鼠脊髓对甲醛痛刺激的反应及氯胺酮的影响。 设计：均衡随机的动物实验。 单位：徐州医学院附属医院麻醉科和江苏省麻醉学重点实验室。 材料：实验于2000-01／03在徐州医学院江苏省麻醉学重点实验室进行。取SD大鼠30只，用均衡随机方法分为6组。甲醛组6只，甲醛＋氯胺酮组6只，氯胺酮＋甲醛组6只，氯胺酮组6只。甲醛＋生理盐水组3只，生理盐水组3只，各组雌雄比例相同。 方法：④甲醛组：体积分数为0．05的甲醛200μL一侧前爪掌心皮下注射，刺激1h。②甲醛＋氯胺酮组：甲醛痛刺激10min后腹腔注射100mg／kg氯胺酮1h。③氯胺酮＋甲醛组：腹腔注射氯胺酮10min，后再行甲醛痛刺激1h。④氯胺酮组：腹腔注射同等剂量氯胺酮1h。⑤甲醛＋生理盐水组：甲醛痛刺激10min后腹腔注射等容（10mL／kg）的生理盐水1h。⑥生理盐水组：腹腔注射等容生理盐水1h。 主要观察指标：①各组大鼠行为学表现。②取脊髓切片，用c-fos基因免疫组化法和NADPH-d组化技术染色，观察大鼠脊髓背角4层（Ⅰ～Ⅱ层，Ⅲ～Ⅳ层，Ⅴ～Ⅵ层，Ⅶ～Ⅹ层）切片Fos样免疫阳性神经元（FLI）和FLI／NOS双标记神经元的数目变化。 结果：30只大鼠全部进入结果分析。①行为学变化：甲醛组及甲醛＋生理盐水组大鼠注射甲醛后，出现痛反应；注射氯胺酮的大鼠，注射后数分钟内翻正反射消失，无明显的痛行为表现，而呈持续睡眠状态。至灌注时翻正反射仍未恢复。②FLI神经元表达：甲醛组及甲醛＋生理盐水组大鼠注射侧脊髓背角出现大量FLI阳性神经元，主要分布在脊髓背角Ⅰ～Ⅱ层；氯胺酮＋甲醛组、甲醛＋氯胺酮组大鼠脊髓FLI细胞的分布与甲醛组及甲醛＋生理盐水组基本相似，但FLI阳性细胞数量显著减少（P〈0．01）；氯胺酮组和生理盐水组大鼠脊髓未见或偶见FLI阳性细胞。③FLI／NOS双标记神经元表达：氯胺酮＋甲醛组、甲醛＋氯胺酮组脊髓背角Ⅰ～Ⅱ层双标记神经元数目显著少于甲醛组及甲醛＋生理盐水组[（1&;#177;1），（1&;#177;1），（7&;#177;3），（8&;#177;3）个／切片，P〈0．01]，氯胺酮组和生理盐水组无表达。 结论：同侧相应脊髓节段的某些神经元参与了化学性致痛信息的传导和调控，氯胺酮通过抑制这些神经元的活动而产生抗伤害作用；此作用与抑制脊髓内一氧化氮合酶阳性神经元的活性有关。     

雌激素对去卵巢大鼠中缝核簇5-羟色胺能神经元的影响

目的:通过观察雌二醇对去卵巢大鼠中缝核簇5-羟色胺(5-hydroxytryptamine,5-HT)免疫阳性物质表达的影响,探讨围绝经期潮热发病机制。方法:实验于2003-09/2004-01在解放军第四军医大学神经生物研究所形态学实验室完成。成年雌性SD大鼠18只,解放军第四军医大学实验动物中心提供,体质量200～250g。清洁级动物,许可证号为SCXK(军)2002-005。采用酶联免疫吸附试验测定血清激素水平,用免疫组织化学方法和图像分析技术观察大鼠中缝核簇5-HT样阳性物质的表达。结果:5-HT样阳性反应产物在大鼠中缝背核、中缝正中核表达较多,去卵巢组大鼠中缝背核、中缝正中核5-HT样阳性细胞数(82.5±17.7)及吸光度(5.12±0.46)都低于假去势组(164.1±15.4,5.90±0.51)(P<0.05),去卵巢雌激素组大鼠中缝背核、中缝正中核5-HT样阳性神经元(149.5±13.4)及吸光度(5.80±0.41)都与假去势组类似,差异无显著性意义(P>0.05)。结论:雌激素可改变大鼠中缝背核、中缝正中核5-HT样阳性物质表达,从而影响其神经元的功能,导致绝经期潮热发生。     

中缝背核介导缰核对大鼠呼吸和行为的影响

目的：观察缰核-中缝背核下行通路对大鼠呼吸、血压的影响。方法：实验于2004-10／12在吉林大学基础医学院生理学实验室完成。取Wistar大鼠25只随机分为两组：①电刺激缰核组（n=17）：经气管插管，采用不锈钢同心圆刺激电极电刺激缰核，电极外壳直径为0．4mm，内芯直径为0．2mm，两极在生理盐水中直流电阻为40～60kΩ。刺激强度为0．10-0．25mA，刺激持续时间5s。②电损毁中缝背核组（n=8）：采用刺激强度为0．05mA的直流电刺激损毁中缝背核。在损毁中缝背核前后，刺激缰核，方法同前。应用胸廓皮肤连接张力换能器及股动脉插管的方法记录大鼠刺激缰核前后的呼吸频率及动脉血压。结果：25只大鼠进入结果分析。①电刺激缰核组大鼠刺激缰核后呼吸频率较刺激前加快【（146．7&;#177;47．5），（78．1&;#177;12，6）次／min，P〈0．011，动脉血压较刺激前升高【（141.4&;#177;18．0），（89．5&;#177;10．5）mmHg（1mmHg=0．133kPa），P〈0．001】。②电损毁中缝背核组大鼠损毁中缝背核后刺激缰核，呼吸频率增加值低于损毁前【（28．5&;#177;18．9），（84．5&;#177;32．5）次／min，P〈0．051，动脉血压升高值也明显低于损毁前【（24．1&;#177;14．3），（50．4&;#177;18．8）mmHg，P〈0．01]．呼吸频率增加效应被阻断66．8％。升压反应被阻断53．6％。结论：缰核对大鼠呼吸运动和心血管活动具有调节作用。缰核的某些功能活动可能通过中缝背核下行通路实现，中缝背核也能介导缰核引起的呼吸和心血管效应，在呼吸和心血管活动调节中，缰核和中缝背核两者互为条件、互为依赖、相互影响。     

"免疫-脑通讯"通路中延髓内脏带至下丘脑室旁核儿茶酚胺能作用的实验研究

背景脂多糖(1ipopolysaccharide,LPS)作为一种多克隆免疫激发剂刺激免疫细胞,来模拟免疫激发状态,观察延髓内脏带(medullary visceral zone,MVZ)投射至下丘脑室旁核(paraventricular nucleus of hypothalamus,PVN)的儿茶酚胺神经元是否对LPS刺激起反应,为脑功能保护研究提供理论依据.目的观察MVZ投射至PVN的儿茶酚胺神经元是否对脂多糖刺激起反应,探讨MVZ至PVN的儿茶酚胺能通路在"免疫-脑通讯"中的作用.设计以实验动物为研究对象,随机对照的研究.单位一所军医大学的神经外科和神经科学研究所.材料实验在南方医科大学珠江医院神经外科和解放军解放军第四军医大学全军神经科学研究所完成.10只健康清洁级成年SD大鼠由第四军医大学实验动物中心提供.方法将WGA-HRP注入大鼠一侧PVN内,存活48 h后经腹腔注射免疫刺激剂LPS诱发免疫反应,应用WGA-HRP逆行追踪与抗Fos和抗酪氨酸羟化酶(TH)抗体双重免疫组织化学相结合三重标记方法进行染色.主要观察指标观察MVZ中WGA-HRP逆标细胞、Fos蛋白和儿茶酚胺能神经元(以TH为标记物)的分布及表达状况.结果在MVZ内发现7种阳性神经元,即HRP,Fos和TH单标细胞,Fos/HRP,Fos/TH和HRP/TH双标细胞,Fos/HRP/TH三标细胞.Fos/HRP双标记和Fos/HRP/TH三标记细胞分别占总HRP逆行标记细胞的12.5%和39.6%.结论MVZ对脂多糖免疫刺激起反应,并可能将免疫信息经儿茶酚胺能神经元上传至PVN;MVZ可能作为"免疫-脑通讯"的一个中继站,通过"MVZ→PVN"通路起免疫调节作用.     

大鼠脑内Fos蛋白在脂多糖免疫激发过程中的传导通路变化

背景：越来越多的研究事实表明免疫系统不是一个仅有自主调节的孤立系统．而是与中枢神经系统之间存在双向联系的，但中枢神经系统哪些部位参与免疫调节仍是一个尚未解决的问题。目的：研究与神经免疫调节有关的功能神经元在大鼠脑内的分布。设计：随机对照的研究。单位：解放军第一军医大学珠江医院神经外科，解放军第四军医大学神经科学研究所和解放军第四军医大学唐都医院呼吸科。对象：实验在第一军医大学珠江医院神经外科和第四军医大学全军神经科学研究所完成。10只健康清洁级成年SD大鼠由第四军医大学实验动物中心提供。干预：以腹腔注射脂多糖(LPS)为免疫激发模型，采用免疫组织化学抗Fos蛋白ABC方法进行染色。主要观察指标：Fos蛋白在脑内不同区域内的分布。结果：Fos阳性产物多集中分布在大脑额顶皮质、边缘前脑(扣带皮质、梨状皮质、外侧隔核和中央杏仁核等)、丘脑室旁核、下丘脑室旁核、弓状核、视上核、视交叉上核、下丘脑外侧区、中脑导水管周围灰质腹外侧部、外侧臂旁核和延髓内脏带。小脑内无明显Fos分布密集区。结论：LPS诱发的Fos阳性神经元在脑内有相对广泛的分布。     

癫痫发作1h后延髓内脏带区域内反应神经元与星形胶质细胞功能单位的分布特征：激光共聚焦显微镜研究

背景：传统观点认为癫痫是大脑不同区域内神经元出现异常兴奋引起的复杂神经行为紊乱现象。而对星形胶质细胞在癫痫发病中的作用目前研究较少。目的：研究戊四氮诱导大鼠癫痫发作后延髓内脏带内神经元和星形胶质细胞的反应。设计：随机对照的实验研究。地点和材料：实验在南方医科大学珠江医院神经外科实验室和解放军第四军医大学全军神经科学研究所完成。成年健康SD大鼠14只，体质量180-220g，清洁级，由解放军第四军医大学实验动物中心提供。干预：用抗Fos蛋白、抗酪氨酸羟化酶和抗胶质原纤维酸性蛋白的三重免疫荧光组织化学方法结合激光共聚焦显微镜技术，显示癫痫发作1h后延髓内脏带内反应性神经元与星形胶质细胞的分布。主要观察指标：对延髓内脏带内Fos，胶质原纤维酸性蛋白和抗酪氨酸羟化酶阳性细胞的分布及胶质原纤维酸性蛋白阳性星形胶质细胞与神经元的关系进行观察。结果：延髓内脏带内的Fos阳性神经元和胶质原纤维酸性蛋白阳性星形胶质细胞明显增多，三重免疫组化方法显示反应性神经元(Fos阳性)与反应性星形胶质细胞(胶质原纤维酸性蛋白阳性)关系密切，发现3种不同标记的“神经元-星形胶质细胞复合体”：即抗酪氨酸羟化酶 ／Fos ／胶质原纤维酸性蛋白 三标记复合体、抗酪氨酸羟化酶 ／胶质原纤维酸性蛋白 ／Fos-和Fos ／胶质原纤维酸性蛋白 ／抗酪氨酸羟化酶-二标记复合体。结论：延髓内脏带内的神经元和星形胶质细胞在癫痫发作时反应强烈，可能以神经元一星形胶质细胞复合体作为功能单位参与癫痫发病的调节。     

皮内注射对急性内脏炎症痛大鼠的抗伤害效应和对脊髓Fos表达的影响

目的:观察皮内注射对福尔马林诱导的急性内脏炎症痛大鼠是否具有抗伤害效应和对脊髓Fos蛋白表达的影响. 方法:实验选用SD大鼠随机分为7组:单纯福尔马林致炎组(F);0.25%利多卡因实验区皮内注射组(F-0.25%L-IN);0.25%利多卡因实验区外皮内注射组(F-0.25%L-OUT);0.125%利多卡因实验区皮内注射组(F-0.125%L-IN);0.125%利多卡因实验区外皮内注射组(F-0.125%L-OUT);生理盐水实验区皮内注射组(F-S-IN);生理盐水实验区外皮内注射组(F-S-OUT).对各组大鼠分别进行疼痛学评分,每15min为一个时间段,共4次,1h后取出S1脊髓节段以免疫组化法检测FLI阳性神经元. 结果:各组在第一个时间段内疼痛学评分差异无显著性(P＞0.05);在第三、第四个时间段内F组和F-0.25%L-IN、F-0.25%L-OUT、F-S-IN组相比疼痛学评分差异有显著性(P＜0.01)而和F-0.125%L-IN、F-0.125%L-OUT、F-S-OUT相比疼痛学评分差异无显著性(P＞0.05);脊髓Fos阳性神经元数量在F-0.25%L-IN、F-0.25%L-OUT、F-S-IN组均显著减少(P＜0.01). 结论:Fos阳性神经元可能参与了化学性致痛信息的传导和调控.     

The dorsal raphe nucleus as a site of action of the antinociceptive and behavioral effects of the alpha4 nicotinic receptor agonist epibatidine

The mechanisms and sites of action of epibatidine-induced antinociception and side effects are poorly understood. The present study tested the hypothesis that the serotonergic dorsal raphe nucleus is a site of action of epibatidine. Behavioral responses of rats to hindpaw formalin injection were compared after direct administration of epibatidine into the dorsal raphe and after subcutaneous administration. Different groups of rats were injected with formalin into the rear paw after administration of either epibatidine (0.01, 0.015, 0.03, and 0.06 microg) in the dorsal raphe or epibatidine (2.5-5 microg/kg) subcutaneously. Assessment of pain related behavior was done evaluating the incidence of favoring, lifting, and licking of the injected paw in the different groups. Abnormal behavior (freezing) was also recorded. Epibatidine was at least 100 times more potent when administered into the dorsal raphe nucleus versus systemically, implicating this nucleus as a site of action of the analgesic effects of epibatidine. Thus, epibatidine (0.015, 0.03, and 0.06 microg) in the dorsal raphe resulted in a significant lower pain score in the second phase of the formalin test compared with control rats and was as effective as subcutaneous epibatidine. The analgesic effects of epibatidine were regionally selective in that administration of epibatidine within the periaqueductal gray area but outside the dorsal raphe area was not analgesic. The highest doses of intraraphe epibatidine (i.e., 0.03-0.06 microg) also produced "freezing" behavior immediately after injection, which was relatively short-lived compared with the analgesic effect. Together, the results implicate the dorsal raphe nucleus as a target for the analgesic and perhaps anxiogenic effects of epibatidine.     

大鼠脑干孤束核中神经激肽B受体神经元在内脏痛信息传递与整合中的作用

背景 脑干孤束核是内脏痛信息向高位脑中枢传递的一个关键的中继站.形态学证据表明,大鼠孤束核中分布有大量的神经激肽 B受体( neurokinin B receptors, NKR).然而,孤束核中表达 NKR的神经元是否参与内脏痛信息的传入与整合目前仍不清楚. 目的 阐明孤束核中表达 NKR的神经元在脑肠通路中传递内脏痛信息中的作用. 设计 随机的对照实验性研究. 地点和对象 12只 SD大鼠购自第四军医大学实验动物中心.大鼠均为雄性,体质量 220～ 250 g,用随机数字表法分为实验组和对照组,每组各 6只. 干预 6只雄性大鼠吸入麻醉后,将 2 mL 50 g/L的乙酸经导管注入大鼠升结肠内, 20 s后再注入 5 mL生理盐水冲洗结肠.对照组大鼠则注射等体积的磷酸缓冲液( 0.01 mol/L). 24 h后大鼠开胸经心脏灌流 40 g/L的甲醛.灌注毕后取出鼠脑修块,然后将含有孤束核的脑块在 300 g/L的蔗糖溶液中浸泡过夜,冰冻切片机切片.用抗 FOS抗体和抗 NKR抗体行免疫组化双重标记染色.免疫组化由第一作者完成,动物模型构建由第二作者完成,第三及第四作者负责免疫组化结果评估. 主要观察指标 孤束核中 NKR和 FOS蛋白的共表达. 结果 孤束核各个亚核中均有大量的 NKR免疫阳性的神经元,但在内侧亚核和联合亚核中尤其浓密.阳性产物分布在细胞膜和树突上;胃肠道给予甲醛刺激后,表达 FOS蛋白的神经元主要分布在孤束核的内侧亚核和联合亚核. NKR和 FOS蛋白双重标记神经元的胞核为黑色,而胞膜为棕黄色.在本研究中,双重标记神经元分别占所有 NKR或 FOS免疫阳性神经元的 37%和 42%. 结论在乙酸诱导的炎症性肠病大鼠孤束核中大约有 1/3的 NKR免疫阳性神经元表达 FOS蛋白,提示这些神经元可能参与了内脏痛信息的传递与整合.     

氯胺酮对甲醛致痛诱导大鼠脊髓背角神经元兴奋性的抑制

背景:氯胺酮是否可通过影响脊髓水平的伤害性信息的传递而发挥抗伤害作用尚不清楚;一氧化氮在脊髓水平主要参与痛觉过敏的形成和发展,可诱导Fos表达,但其是否参与了氯胺酮对痛信号的转导或调控的机制不明。目的:观察大鼠脊髓对甲醛痛刺激的反应及氯胺酮的影响。设计:均衡随机的动物实验。单位:徐州医学院附属医院麻醉科和江苏省麻醉学重点实验室。材料:实验于2000-01/03在徐州医学院江苏省麻醉学重点实验室进行。取SD大鼠30只,用均衡随机方法分为6组熏甲醛组6只,甲醛 氯胺酮组6只,氯胺酮 甲醛组6只,氯胺酮组6只,甲醛 生理盐水组3只,生理盐水组3只,各组雌雄比例相同。方法:①甲醛组:体积分数为0.05的甲醛200μL一侧前爪掌心皮下注射,刺激1h。②甲醛 氯胺酮组:甲醛痛刺激10min后腹腔注射100mg/kg氯胺酮1h。③氯胺酮 甲醛组:腹腔注射氯胺酮10min后再行甲醛痛刺激1h。④氯胺酮组:腹腔注射同等剂量氯胺酮1h。⑤甲醛 生理盐水组:甲醛痛刺激10min后腹腔注射等容(10mL/kg)的生理盐水1h。⑥生理盐水组:腹腔注射等容生理盐水1h。主要观察指标:①各组大鼠行为学表现。②取脊髓切片,用c-fos基因免疫组化法和NADPH-d组化技术染色,观察大鼠脊髓背角4层(Ⅰ～Ⅱ层,Ⅲ～Ⅳ层,Ⅴ～Ⅵ层,Ⅶ～Ⅹ层)切片Fos样免疫阳性神经元(FLI)和FLI/NOS双标记神经元的数目变化。结果:30只大鼠全部进入结果分析。①行为学变化:甲醛组及甲醛 生理盐水组大鼠注射甲醛后,出现痛反应;注射氯胺酮的大鼠,注射后数分钟内翻正反射消失,无明显的痛行为表现,而呈持续睡眠状态,至灌注时翻正反射仍未恢复。②FLI神经元表达:甲醛组及甲醛 生理盐水组大鼠注射侧脊髓背角出现大量FLI阳性神经元,主要分布在脊髓背角Ⅰ～Ⅱ层;氯胺酮 甲醛组、甲醛 氯胺酮组大鼠脊髓FLI细胞的分布与甲醛组及甲醛 生理盐水组基本相似,但FLI阳性细胞数量显著减少(P<0.01);氯胺酮组和生理盐水组大鼠脊髓未见或偶见FLI阳性细胞。③FLI/NOS双标记神经元表达:氯胺酮 甲醛组、甲醛 氯胺酮组脊髓背角Ⅰ～Ⅱ层双标记神经元数目显著少于甲醛组及甲醛 生理盐水组眼(1±1),(1±1),(7±3),(8±3)个/切片,P<0.01演,氯胺酮组和生理盐水组无表达。结论:同侧相应脊髓节段的某些神经元参与了化学性致痛信息的传导和调控,氯胺酮通过抑制这些神经元的活动而产生抗伤害作用;此作用与抑制脊髓内一氧化氮合酶阳性神经元的活性有关。     

Effects of intra‐basolateral amygdala administration of rimonabant on nociceptive behaviour and neuronal activity in the presence or absence of contextual fear

The basolateral amygdala (BLA) contains a high density of cannabinoid CB₁ receptors and is critically involved in pain and fear‐related behaviour. We investigated the effects of bilateral intra‐BLA administration of the CB₁ receptor antagonist/inverse agonist, rimonabant, on formalin‐evoked nociceptive behaviour, fear‐conditioned behaviour including analgesia, and associated brain regional alterations in Fos expression in rats. Intra‐BLA administration of rimonabant significantly reduced formalin‐evoked nociceptive behaviour in the absence, but not presence, of conditioned fear. Rimonabant attenuated a formalin‐evoked reduction in freezing while emitting 22 kHz ultrasonic vocalisation in the early part of the fear expression trial. Formalin‐evoked nociceptive behaviour was associated with increased Fos immunoreactivity (FI) in the CA2/3 region of the hippocampus and rostral ventromedial medulla, effects attenuated by intra‐BLA rimonabant. Formalin also decreased FI in the cingulate cortex, an effect which was not observed in fear‐conditioned rats. Contextually‐induced fear was associated with increased FI in the dorsal caudal periaqueductal grey in the absence, but not presence, of formalin‐evoked nociceptive tone. In conclusion, bilateral intra‐BLA administration of rimonabant reduces nociceptive behaviour in a model of tonic, persistent inflammatory pain, an effect associated with reduced activation of neurons in the CA2/3 hippocampus and rostral ventromedial medulla. The data also provide evidence for differential pain‐ and fear‐related brain regional activity in the presence or absence of contextually‐induced aversion and nociceptive tone.     

Trigeminal nociception-induced cerebral Fos expression in the conscious rat

Little is known about trigeminal nociception-induced cerebral activity and involvement of cerebral structures in pathogenesis of trigeminovascular headaches such as migraine. Neuroimaging has demonstrated cortical, hypothalamic and brainstem activation during the attack and after abolition with sumatriptan. This has led to the conclusion that the dorsal raphe and locus coeruleus may initiate events that generate migraneous headache. Using a conscious rat model of trigeminal nociception and cerebral Fos expression as histochemical markers of neuronal activity, we characterized the pattern of brain activity after noxious trigeminal stimulation with capsaicin (250 and 1000 nm). A significantly increased Fos immunoreactivity was found in the trigeminal nucleus caudalis (layers I and II), the area postrema, the nucleus of the solitary tract, the parvicellular reticular nucleus, the locus coeruleus, the parabrachial nucleus and the raphe nuclei. In addition, the ventrolateral periaqueductal grey, the intralaminar thalamic and various hypothalamic areas, showed an enhanced Fos expression after the intracisternal administration of capsaicin. Other responding areas were the amygdala, the upper lip and forelimb regions of the primary somatosensory cortex, and the insula. Many of these areas participate in (anti)-nociception, although we cannot exclude the possibility that in conscious animals the pain-associated physiological and behavioural responses that are an intrinsic and necessary part of coping with pain have generated the increased Fos expression. Trigeminal stimulation-induced locus coeruleus, dorsal raphe and hypothalamic activation are opposed to a suggested pathogenic role of these nuclei in migraine and cluster headache, respectively.     

Genetic evidence for the correlation of deep dorsal horn Fos protein immunoreactivity with tonic formalin pain behavior.

The formalin test is commonly used as a model of persistent pain. Besides producing pain behavior, hind paw formalin injection induces the expression of the immediate-early gene, c-fos. A current controversy is whether noxious stimulus-induced Fos protein immunoreactivity can be considered a proxy (biomarker) of nociception in the spinal cord. We investigated this issue by exploiting our recent demonstration of genotype-dependent behavioral differences in response to formalin injection among inbred mouse strains. Accordingly, 6 inbred and 2 outbred strains were administered formalin (5% in 25 microL) into the ventral hind paw, monitored for licking behavior, and then sacrificed at 90 minutes after injection for Fos protein immunocytochemistry. Significant strain differences were observed in both licking behavior and Fos counts in superficial and deep laminae. We observed a significant correlation among strains between licking behavior in the late phase (10 to 60 minutes) of the formalin test and Fos expression in laminae V-VI (but not laminae I-II) of the dorsal horn (r = 0.94). These findings reinforce the use of the Fos technique to study the neuronal processing underlying pain but suggest that Fos labeling reliably reflects tonic pain behavior only in neurons located in the neck of the dorsal horn in mice.     

Comparison of the influence of rostral and caudal raphe neurons on the adrenal secretion of catecholamines and on the release of adrenocorticotropin in the cat

Neuroendocrine and autonomic responses were assessed in chloralose-anesthetized cats after chemical stimulation of medial brain-stem regions, including those that influence nociceptive input to the medullary or spinal dorsal horn. Microinjections of L-glutamate (0.5 M, 160 nl) were directed at the following rostral and caudal raphe nuclei: the periaqueductal gray (PAG), the dorsal raphe nucleus (DR), the raphe magnus (RM), and the raphe obscurus/raphe pallidus (Ro/Rpa). Activation of DR neurons evoked a significant increase in the adrenal secretion of epinephrine (+2.6 +/- 1.1 ng/min, P less than 0.01) that returned towards prestimulus values by 6 min, whereas microinjections into other raphe nuclei had no consistent effect. Activation of Ro/Rpa neurons evoked an increase in the plasma concentration of adrenocorticotropin (ACTH, +47.9 +/- 12.3 pg/ml, P less than 0.01), whereas microinjections into other raphe nuclei did not affect ACTH. Arterial pressure increased significantly after activation of PAG (+7.5 +/- 2.1 mm Hg, P less than 0.01) or of DR (+4.8 +/- 2.0 mm Hg, P less than 0.05) neurons, whereas heart rate increased significantly (P less than 0.05) after stimulation of cells within the Ro/Rpa. Glutamate microinjections within the RM, a raphe nucleus that exerts a significant descending influence on nociceptive input to the medullary and to the spinal dorsal horns, had no consistent effect on any measured variable. No evidence was seen to suggest that chemical activation of neurons within raphe nuclei inhibited the adrenal secretion of catecholamines or inhibited the release of ACTH. The results indicated that glutamate activation of neurons within different raphe nuclei evoked non-uniform effects on neuroendocrine and autonomic function. Further, these data suggested that the neural substrate underlying the control of the adrenal secretion of catecholamines and of the release of ACTH in response to activation of raphe neurons is likely distinct from that which contributes to the descending influence on nociceptive input to the medullary and spinal dorsal horn.     

Nucleus reticularis gigantocellularis and nucleus raphe magnus in the brain stem exert opposite effects on behavioral hyperalgesia and spinal Fos protein expression after peripheral inflammation

Previous findings indicate that the brain stem descending system becomes more active in modulating spinal nociceptive processes during the development of persistent pain. The present study further identified the supraspinal sites that mediate enhanced descending modulation of behavior hyperalgesia and dorsal horn hyperexcitability (as measured by Fos-like immunoreactivity) produced by subcutaneous complete Freund's adjuvant (CFA). Selective chemical lesions were produced in the nucleus raphe magnus (NRM), the nuclei reticularis gigantocellularis (NGC), or the locus coeruleus/subcoeruleus (LC/SC). Compared to vehicle-injected animals with injection of vehicle alone, microinjection of a serotoninergic neurotoxin 5,7-dihydroxytryptamine into the NRM significantly increased thermal hyperalgesia and Fos protein expression in lumbar spinal cord after hindpaw inflammation. In contrast, the selective bilateral destruction of the NGC with a soma-selective excitotoxic neurotoxin, ibotenic acid, led to an attenuation of hyperalgesia and a reduction of inflammation-induced spinal Fos expression. Furthermore, if the NGC lesion was extended to involve the NRM, the behavioral hyperalgesia and CFA-induced Fos expression were similar to that in vehicle-injected rats. Bilateral LC/SC lesions were produced by microinjections of a noradrenergic neurotoxin, DSP-4. There was a significant increase in inflammation-induced spinal Fos expression, especially in the ipsilateral superficial dorsal horn following LC/SC lesions. These results demonstrated that multiple specific brain stem sites are involved in descending modulation of inflammatory hyperalgesia. Both NRM and LC/SC descending pathways are major sources of enhanced inhibitory modulation in inflamed animals. The persistent hyperalgesia and neuronal hyperexcitability may be mediated in part by a descending pain facilitatory system involving NGC. Thus, the intensity of perceived pain and hyperalgesia is fine-tuned by descending pathways. The imbalance of these modulating systems may be one mechanism underlying variability in acute and chronic pain conditions.