胍丁胺抑制福尔马林诱导的脊髓PKCγ,pCREB,c-Fos和c-Jun表达上调

目的研究福尔马林致炎性疼痛脊髓蛋白激酶Cγ(PKCγ),磷酸化的环磷酸腺苷反应元件结合蛋白(pCREB),即刻早期基因c-fos和c-jun表达的变化及胍丁胺对其的影响。方法♂SD大鼠,180～220g,随机分为:①生理盐水组;②福尔马林组;③胍丁胺(160mg·kg-1,ip)组。足底注射5%福尔马林50μl后10、20、120min取L4,5脊髓,通过免疫组化和免疫印迹研究,检测胍丁胺对炎性疼痛脊髓PKCγ、pCREB、c-Fos和c-Jun蛋白表达变化的影响。结果大鼠单侧足底注射5%福尔马林10min后,引起双侧脊髓膜结合PKCγ表达量升高;足底注射20min后,双侧脊髓pCREB表达量升高;足底注射2h后,注射侧脊髓背角c-Fos和c-Jun蛋白表达量升高,注射对侧脊髓c-Fos和c-Jun蛋白表达量没有改变。胍丁胺明显抑制福尔马林所引起的膜结合PKCγ、pCREB、c-Fos和c-Jun蛋白表达量的升高(P<0.01)。结论炎性疼痛引起脊髓膜结合PKCγ、pCREB、c-Fos和c-Jun蛋白表达上调可能参与疼痛及痛觉过敏的产生。胍丁胺的镇痛机制可能与抑制PKCγ、pCREB、c-Fos和c-Jun等痛觉相关的信号转导分子的表达有关。     

胍丁胺对炎性疼痛的镇痛作用及对吗啡镇痛作用的影响

目的观察胍丁胺对炎性疼痛的镇痛作用及其对吗啡镇痛作用的影响,研究胍丁胺的镇痛作用是否与激动咪唑啉受体或影响受体前谷氨酸和γ-氨基丁酸(gamma-aminobutyr-icacid,GABA)释放有关。方法应用福尔马林致大鼠炎性疼痛模型,观察胍丁胺镇痛和增强吗啡镇痛的作用。应用高效液相色谱技术测定胍丁胺对脊髓切片孵育液中谷氨酸和GABA基础释放量及对高钾诱发神经元去极化引起神经递质释放的影响。结果单侧足底注射5%福尔马林使大鼠出现明显的双相伤害性行为反应。胍丁胺抑制福尔马林引起的第二相疼痛行为反应及痛觉过敏,并增强吗啡对第二相疼痛的镇痛作用,但在第一相疼痛过程中,无明显镇痛和增强吗啡镇痛的作用。咪唑啉受体拮抗剂咪唑克生不能拮抗胍丁胺镇痛及增强吗啡镇痛的作用。1~1000μmol.L-1胍丁胺对脊髓谷氨酸和GABA的基础释放量和高钾诱发谷氨酸和GABA释放量的升高均没有影响。结论胍丁胺对炎性疼痛具有明确的镇痛作用,并明显增强吗啡的镇痛效果,其镇痛机制可能与咪唑啉受体无关,也不是通过在受体前水平抑制谷氨酸或促进GABA释放来实现的。     

N~ω-硝基-L-精氨酸甲酯可抑制吗啡镇痛耐受大鼠的痛觉过敏以及脊髓和中脑c-Fos表达

目的:在福尔马林炎性疼痛模型观察非特异性一氧化氮合成酶(NOS)抑制剂/Nω-硝基-L-精氨酸甲酯(L-NAME)对吗啡镇痛耐受大鼠疼痛行为以及脊髓和中脑c-Fos表达的影响。方法:将24只健康成年SD大鼠随机平均分为4组:生理盐水(NS)组,即对照组,皮下注射(sc)NS1ml;L-NAME组、Mor组和L-NAME+Mor组,为处理组,分别scL-NAME20mg·kg-1、吗啡10mg·kg-1、L-NAME20mg.kg-1和吗啡10mg.kg-1。各组给药均为每天2次,连续7d。在d8上午最后1次给药后30min,于大鼠左后足掌侧sc5%福尔马林0.1ml,记录每5min内舔咬注射足时间(TTSLI),观察时间为50min。记录完毕后取脊髓和中脑做c-Fos免疫组化检查。结果:与NS组相比,L-NAME组的Ⅱ相TTSLI显著缩短,Mor组的Ⅰ相和Ⅱ相TTSLI显著延长,L-NAME+Mor组的Ⅰ相和Ⅱ相TTSLI均显著缩短。免疫组化检查结果显示,与NS组相比,L-NAME组、L-NAME+Mor组注射足同侧和对侧脊髓以及中脑导水管周围灰质(PAG)神经元的c-Fos样免疫反应阳性面积显著降低,但Mor组的F-LI阳性面积显著性增加。结论:吗啡镇痛耐受大鼠接受福尔马林刺激后表现为痛觉过敏,其脊髓和中脑PAG神经元的c-Fos表达增加,L-NAME可抑制吗啡镇痛耐受大鼠的痛觉过敏,并可抑制脊髓和中脑PAG神经元的c-Fos表达。本研究结果提示脊髓和中脑的一氧化氮系统与吗啡镇痛耐受时痛觉过敏的发生密切相关。     

GABA_A受体部分介导丙泊酚在大鼠脊髓水平的抗伤害作用

目的研究丙泊酚在脊髓水平对大鼠伤害性感受的影响及GABAA受体在其中可能的作用。方法Sprague-Daw-ley(SD)♀大鼠随机分组,丙泊酚(Propofol,Pro)和荷包牡丹碱(B icucu lline,B ic)采用鞘内注射(ith)。行为学实验采用热板法和福尔马林实验,分别以舔后爪潜伏时间(Hot-p latelatency,HPL)和疼痛(累计)评分为指标。免疫组化方法观察丙泊酚鞘内给药对福尔马林单侧足底皮下注射诱发的脊髓背角Fos蛋白表达的影响。结果行为学部分:在两种疼痛模型中,鞘内注射丙泊酚(10 g.L-1)产生镇痛作用(P<0.01)。在热板法实验中,鞘内注射丙泊酚(10 g.L-1)产生的镇痛作用在10、20、30和40 min时间点可被鞘内给予Bic(0.01 g.L-1)分别拮抗81%、55%、81%和97%(均P<0.01)。在福尔马林实验中,鞘内注射丙泊酚(10 g.L-1)减少的福尔马林疼痛评分在30 min时间点可被Bic(0.01 g.L-1)相同部位注射拮抗67%(P<0.01)。免疫组化部分:鞘内注射丙泊酚(10 g.L-1)明显减少福尔马林单侧足底皮下注射引起的大鼠同侧腰段脊髓背角各层Fos免疫反应样神经元(Fos-like immunoreactivity,FLI)阳性细胞数(P<0.01);鞘内注射丙泊酚(10 g.L-1)产生的效应可被鞘内注射Bic(0.01 g.L-1)部分拮抗(P<0.01)。结论鞘内注射丙泊酚在大鼠可产生镇痛作用;GABAA受体部分介导了丙泊酚的以上作用。     

胍丁胺通过抑制大鼠脊髓JNK通路对抗慢性吗啡耐受

目的探讨脊髓c-Jun蛋白氨基末端激酶(c-Jun N-ter-minal kinase,JNK)在胍丁胺抗慢性吗啡镇痛耐受中的作用。方法 SD大鼠皮下注射吗啡(10 mg.kg-1,每日2次,连续9 d)建立慢性吗啡镇痛耐受模型。应用热水甩尾法测定甩尾潜伏期观察吗啡的镇痛效果。应用免疫印迹法(Westernblot)检测脊髓总JNK和磷酸化(p)-JNK蛋白表达;免疫组织化学染色法检测脊髓p-JNK的免疫反应性(immnunoreac-tivity,IR)。结果吗啡耐受大鼠脊髓背角p-JNK-IR明显增多,p-JNK蛋白表达也增多,而总JNK没有改变。胍丁胺(10 mg.kg-1)不仅拮抗吗啡镇痛耐受,而且明显地抑制脊髓背角p-JNK-IR增多及p-JNK蛋白表达上调。结论抑制慢性吗啡注射所引起的脊髓JNK的激活可能是胍丁胺抗吗啡镇痛耐受的作用机制之一。     

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。     

Ciproxifan的镇痛作用及其对脊髓背角神经元的影响

目的观察ciproxifan在福尔马林痛觉试验中的镇痛作用,并探讨其可能的机制。方法小鼠足底皮下注射2％福尔马林,观察ciproxifan的镇痛作用;并用免疫组化和Westernblot法观察ciproxifan对小鼠脊髓背角神经元中c—fos的表达和nNOS表达及活化的影响。结果Ciproxifan在福尔马林痛觉试验中,能明显抑制小鼠Ⅰ相和Ⅱ相的痛觉行为,差异有统计学意义（P〈0．05）。同时,ciproxifan能抑制小鼠脊髓背角神经元c—fbs的表达和nNOS在细胞内的移位。结论Ciproxifan能产生镇痛作用,该作用可能与其抑制脊髓背角神经元的激活,从而抑制nNOS的活化有关。     

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。     

Ciproxifan在小鼠痛觉传导调节机制中的作用

目的:研究组胺H3受体拮抗剂ciproxifan(CPF)在小鼠痛觉传导调节过程中的作用及其机制.方法:用3种不同的小鼠痛觉模型(热板法、扭体法和福尔马林实验)观察CPF的镇痛作用.同时用特异性组胺脱羧酶(HDC)抑制药α-氟甲基组胺酸(α-FMH),观察组胺在CPF发挥镇痛效应过程中所起的作用.在福尔马林致痛模型中,还测定了小鼠脑、脊髓和血清中一氧化氮(NO)和前列腺素E2(PGE2)的含量.结果:热板实验中,CPF 1 mg%.皮下注射福尔马林能引起2个时相(Ⅰ相、Ⅱ相)的痛反应.这种由福尔马林引起的2个时相的痛反应均可明显被CPF 0.3, 1, 3 mg*kg-1抑制. 在3种致痛模型中,CPF的镇痛效应均可被α-FMH 50 mg*kg-1逆转.使用福尔马林后,小鼠脑和脊髓中NO和PGE2水平升高,而CPF能明显抑制这种升高作用,该抑制作用不被α-FMH所拮抗.但CPF对血清中NO和PGE2的浓度没有影响.结论:组胺H3受体拮抗药CPF对多种性质刺激引起的疼痛均有镇痛作用,对福尔马林引起的炎性疼痛和非炎性疼痛都有效.CPF的这种镇痛作用可能与其促进组胺释放有关;同时脑和脊髓中的NO和PGE2可能参与了CPF的镇痛作用.     

脊髓背角神经元上调Nav1.8通道参与缺血再灌注损伤后痛觉过敏的机制

目的观察鞘内注射钠通道抑制剂619C89对脊髓缺血再灌注损伤引起的痛觉过敏大鼠的痛阈、脊髓背角神经元中Nav1.8通道表达的影响。方法 SD大鼠随机分为3组:假手术组(S组)、痛觉过敏组(H组,缺血再灌注前3 d鞘内注射30μL生理盐水)、钠通道抑制剂组(I组,缺血再灌注前3 d鞘内注射619C895μg/30μL)。S组仅暴露主动脉弓而不结扎,其他各组开胸后无创动脉夹夹闭主动脉弓14 min后再开放,建立SCIRI引起的痛觉过敏模型。各组手术前均于L_(5-6)鞘内置管并连续注射3 d。术后1、3、5、7、14 d分别测定各组大鼠的热痛阈及机械性痛阈;取第4~6节腰段脊髓,采用免疫双荧光法观察背角神经元状态及其Nav1.8的表达,Real time-PCR法检测各组大鼠脊髓组织Nav1.8表达。结果与S组相比,术后各观察点(尤以第7天为著)H组大鼠热痛阈和机械性痛阈降低,损伤后7 d脊髓组织中Nav1.8 mRNA的表达增加(P<0.05);I组大鼠热痛阈和机械性痛阈值明显提高(P<0.05),脊髓组织中Nav1.8 mRNA的表达降低(P<0.05)。免疫双荧光染色显示,损伤后7 d,H组大鼠脊髓背角Nav1.8的荧光强度明显增加,且主要表达在NeuN表达阳性的神经元的胞浆中;且与S组相比,H组中NeuN/Nav1.8双阳性的细胞数量明显增多,而I组双阳性的细胞数量减少(P<0.05)。结论脊髓背角神经元通过上调Nav1.8通道参与缺血再灌注损伤后痛觉过敏的形成。     

Efficacy of gut lavage,hemodialysis, and hemoperfusion in the therapy of paraquat or diquat intoxication

Clinical and in vitro investigations were carried out to test the efficacy of gut lavage, hemodialysis, and hemoperfusion in the treatment of poisoning with paraquat or diquat. In a patient suffering from diquat intoxication 130 times more diquat was removed by gut lavage 30 h after ingestion than was removed by complete aspiration of the gastric contents.Determination of in vitro clearances for paraquat and diquat by hemodialysis showed that, at serum concentrations of 1–2 ppm, such as are frequently encountered in poisoning in man, toxicologically relevant quantities of herbicide cannot be removed from the body. At a concentration of 20 ppm, on the other hand, hemodialysis proved to be effective, the clearance being 70 ml/min at a blood flow rate of 100 ml/min. The efficacy of hemoperfusion with coated activated charcoal was on the whole better. Especially at concentrations around 1–2 ppm, the clearance values for hemoperfusion were some 5–7 times higher than those for hemodialysis.In a patient suffering from paraquat poisoning, both hemodialysis as well as hemoperfusion were carried out. The in vitro results could be confirmed: At serum concentrations of paraquat less than 1 ppm no clearance could be obtained by hemodialysis while by hemoperfusion with activated charcoal quite high clearance values were measured and the serum level dropped down to zero.

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Zusammenfassung Klinische Untersuchungen und Laboratoriumsversuche wurden durchgeführt, um die Wirksamkeit von Darmspülung, Hämodialyse und Hämoperfusion bei Paraquat- und Deiquat-Vergiftungen zu prüfen.Bei einem Patienten wurde 30 Std nach Deiquat-Aufnahme durch Darmspülung 130mal mehr Deiquat entfernt als durch vollständige Aspiration des Mageninhaltes. In vitro-Versuche ergaben, daß bei Blutserumkonzentrationen von 1–2 ppm, die bei Vergiftungen oft gemessen werden, durch Hämodialyse keine toxikologisch relevanten Paraquat- oder Deiquat-Mengen entfernt werden können. Dagegen erwies sich die Hämodialyse bei 20 ppm und einer Blutumlaufgeschwindigkeit von 100 ml/min mit einer Clearance von 70 ml/min als wirksam. Die Hämoperfusion mit beschicheter Aktivkohle war in diesen Versuchen aber eindeutig überlegen, denn insbesondere bei Konzentrationen um 1–2 ppm waren die Clearance-Werte 5–7mal höher als bei der Hämodialyse.Die in vitro-Ergebnisse wurden bei einem Patienten mit einer Paraquat-Vergiftung bestätigt: Bei Konzentrationen unter 1 ppm war die Hämodialyse wirkungslos, während durch Hämoperfusion relativ hohe Clearance-Werte erreicht wurden, so daß der Serumspiegel rasch unter die Nachweisgrenze abfiel.

     

In vitro studies on sterically stabilized liposomes (SL) as enzyme carriers in organophosphorus (OP) antagonism

This study describes a new approach for organophosphorous (OP) antidotal treatment by encapsulating an OP hydrolyzing enzyme, OPA anhydrolase (OPAA), within sterically stabilized liposomes. The recombinant OPAA enzyme was derived from Alteromonas strain JD6. It has broad substrate specificity to a wide range of OP compounds: DFP and the nerve agents, soman and sarin. Liposomes encapsulating OPAA (SL)* were made by mechanical dispersion method. Hydrolysis of DFP by (SL)* was measured by following an increase of fluoride ion concentration using a fluoride ion selective electrode. OPAA entrapped in the carrier liposomes rapidly hydrolyze DFP, with the rate of DFP hydrolysis directly proportional to the amount of (SL)* added to the solution. Liposomal carriers containing no enzyme did not hydrolyze DFP. The reaction was linear and the rate of hydrolysis was first order in the substrate. This enzyme carrier system serves as a biodegradable protective environment for the recombinant OP-metabolizing enzyme, OPAA, resulting in prolongation of enzymatic concentration in the body. These studies suggest that the protection of OP intoxication can be strikingly enhanced by adding OPAA encapsulated within (SL)* to pralidoxime and atropine.     

Aquatic Insects and Trace Metals: Bioavailability,Bioaccumulation, and Toxicity

Abstract

The uptake of metals from food and water sources by insects is thought to be additive. For a given metal, the proportions taken up from water and food will depend both on the bioavailable concentration of the metal associated with each source and the mechanism and rate by which the metal enters the insect. Attempts to correlate insect trace metal concentrations with the trophic level of insects should be made with a knowledge of the feeding relationships of the individual taxa concerned. Pathways for the uptake of essential metals, such as copper and zinc, exist at the cellular level, and other nonessential metals, such as cadmium, also appear to enter via these routes. Within cells, trace metals can be bound to proteins or stored in granules. The internal distribution of metals among body tissues is very heterogeneous, and distribution patterns tend to be both metal and taxon specific. Trace metals associated with insects can be both bound on the surface of their chitinous exoskeleton and incorporated into body tissues. The quantities of trace meals accumulated by an individual reflect the net balance between the rate of metal influx from both dissolved and particulate sources and the rate of metal efflux from the organism. The toxicity of metals has been demonstrated at all levels of biological organization: cell, tissue, individual, population, and community. Much of the literature pertaining to the toxic effects of metals on aquatic insects is based on laboratory observations and, as such, it is difficult to extrapolate the data to insects in nature. The few experimental studies in nature suggest that trace metal contaminants can affect both the distribution and the abundance of aquatic insects. Insects have a largely unexploited potential as biomonitors of metal contamination in nature. A better understanding of the physico-chemical and biological mechanisms mediating trace metal bioavailability and exchange will facilitate the development of general predictive models relating trace metal concentrations in insects to those in their environment. Such models will facilitate the use of insects as contaminant biomonitors.     

Steroidal sapogenin contents in some domestic plants

In order to find out the values of the steroid resources for the future use. the compositions and contents of steroidal sapogenins from 13 domestic plants have been investigated. As a result,Dioscorea nipponica, D. quinqueloba andSmilax china were found to have large amount of diosgenin. And pennogenin inTrillium kamtschaticum andParis verticillata, yuccagenin inAllium fistulosum, hecogenin inAgave americana and neochlorogenin inSolanum nigum were appeared to be major steroidal sapogenins.     

Alzheimer’s disease – current trends in basic and clinical research. Highlights from the 16th ECNP

Advances in the molecular biological knowledge of neuronal nicotinic acetylcholine receptors (nAChRs) have led to a growing interest by the pharmaceutical industry in the development of novel compounds that selectively modulate nAChR function. The ability of (-)-nicotine, an activator of nAChRs, to enhance attentional aspects of cognition in animals and humans, to exert neuroprotective and anxiolytic-like effects, and presumably to mediate the negative correlation between smoking and Alzheimer's (and Parkinson's) Disease, has focused interest on the potential therapeutic utility of modulators of nAChR function for treatment of some of the deficits associated with these progressive, neurodegenerative conditions. Numerous compounds are known which activate nAChRs and which might serve as lead compounds toward the development of such agents. The pharmacologic diversity of neuronal nAChR subtypes suggests the possibility of developing selective compounds which would have more favourable side-effect profiles than existing agents. This broader class of agents, collectively called cholinergic channel modulators (ChCMs), is anticipated to encompass compounds which would have more favourable side-effect profiles than existing agents, which generally exhibit low selectivity. This selectivity may be achieved by preferentially activating some subtypes of nAChRs (i.e., Cholinergic Channel Activators, ChCAs) or inhibiting the function of other subtypes (Cholinergic Channel Inhibitors, ChCIs). An overview of the biology of nAChRs and the rationale for the use of ChCMs for the treatment of dementia related to neurodegenerative diseases are presented, followed by a discussion of lead compounds and compounds under consideration for clinical evaluation.