不同频率电针刺激对神经痛模型大鼠脊髓背角P物质的影响

目的:观察P物质(Substance P,SP)在慢性坐骨神经压迫损伤(chronic constriction injury,CCI)模型脊髓中表达的变化,探讨电针镇痛的机制是否与脊髓背角中SP表达的变化有关。方法:选择32只雄性、体重180-200 g的SD大鼠,并将其随机均分为4组(n=8)。空白组(Con组)为正常痛阈值大鼠;假电针组(CCI+A组)在损伤的坐骨神经旁置入电针,但无电流刺激;2 Hz组和100Hz组分别给予相应频率电流刺激30 min。在实验开始前和术后1、4、7、14、20、22天记录大鼠的热缩足反射潜伏期(Paw Withdrawal Latency,PWL)和机械刺激缩足反射阈值(Paw Withdrawal Threshold,PWT)。免疫组化方法检测脊髓背角SP的表达。结果:术后20天,电针治疗后,100 Hz组和2 Hz组PWT分别为(7.33±1.42)g和(7.80±1.42)g,均显著高于假电针组(2.60±1.46)g,差异有统计学意义(P0.05)。100 Hz组在术后20天后和2 Hz组在术后14天后PWL值均显著高于假电针组,差异有统计学意义(P0.05)。免疫组化显示:2 Hz组和100 Hz组大鼠脊髓背角中P物质阳性细胞显著低于假电针组(P0.05)。结论:坐骨神经旁电针刺激能够显著减轻CCI模型大鼠热痛觉及机械痛觉过敏,其机制可能与抑制脊髓背角SP的表达有关。     

奥沙利铂周围神经毒性模型大鼠行为学检测方法的比较

目的进行两种大鼠机械性痛觉敏感性测量方法、两种冷刺激缩足反应测量方法的比较研究。方法雌性Wistar大鼠,腹腔注射奥沙利铂4 mg/kg,建立标准奥沙利铂周围神经毒性大鼠模型。检测机械和冷热温度刺激下大鼠行为学变化,并对不同行为学检测方法的特点进行比较分析。结果模型组大鼠较正常组相比50%缩足阈明显降低(P0.05)、出现痛觉过敏及痛觉超敏(P0.05)、冷刺激诱发的缩足次数增多(P0.05),两组大鼠对热痛刺激反应均无明显差异,与临床患者症状表现基本一致。结论 Von Frey纤维丝刺激检测中4 g和15 g方法可更好的模拟临床患者的痛觉过敏、超敏反应;up-down法客观量化的反应出大鼠缩足阈值下降的程度。冷温度刺激中,丙酮喷洒法可较直观的观察大鼠受到冷刺激后的反应。     

吗啡受体拮抗剂翻转电针镇痛的程度决定于电针刺激的频率

电针镇痛能被吗啡受体拮抗剂所对抗,被认为是内源性吗啡样物质参与针刺镇痛的有力证据。给大鼠皮下注射吗啡受体拮抗剂纳洛酮或纳曲酮 1mg/kg, 可以对抗低频和中频(2和15Hz)电针的镇痛效应,但不能对抗高频(100Hz)电针镇痛效应。增加纳洛酮剂量至20mg/kg才能部分对抗 100Hz电针镇痛。根据不同剂量纳洛酮(0.25—20mg/kg)对抗不同频率电针镇痛的剂量效应曲线,求得对2,15和100Hz电针镇痛产生50％翻转作用的纳洛酮剂量分别为 0.53,1.02和 24mg/kg。2—15Hz变频电针的镇痛作用也需用大剂量纳洛酮(20mg/kg)才能阻断。实验表明,在三种频率下,改变电针刺激强度(1,2,3V)并不影响纳洛酮翻转电针镇痛的百分数。以上结果表明,纳洛酮翻转电针镇痛的程度决定于电针的频率,不同频率的电针刺激可能在中枢神经系统中释放出不同的内源性吗啡样物质而发挥镇痛作用。     

中脑导水管周围灰质电刺激与丘脑电刺激对大鼠伤害感知行为的差异调节（英文）

深部脑刺激是一种广泛用于治疗中枢神经及精神疾病的功能型手术疗法。深部脑刺激在临床应用于疼痛治疗起源于半个多世纪以前,能够有效治疗多种类型的顽固疼痛,然而其作用机制尚不清楚。为了进一步探索其神经机制,首先需要建立合适的深部脑刺激治疗疼痛的动物模型。本研究在大鼠的中脑导水管周围灰质腹外侧区(ventrolateral periaqueductal gray,vl PAG)或丘脑腹后外侧核(ventral posterior lateral nucleus,VPL)埋置刺激电极,研究深部脑刺激对正常大鼠急性痛、完全弗式佐剂(complete Freund’s adjuvant,CFA)注射引起的慢性炎症痛大鼠模型以及脊神经结扎(spinal nerve ligation,SNL)手术引起神经病理痛大鼠模型的镇痛效果。主要结果如下:(1)在正常大鼠中,单侧vl PAG刺激能够显著提高双侧足底的热辐射痛阈,即产生显著的双侧镇痛作用;(2)在CFA建立的慢性炎症痛模型中,对侧vl PAG刺激和VPL刺激都能够显著提高CFA侧足底的热辐射痛阈,即产生显著的镇痛作用;(3)在SNL手术引发的慢性神经源性痛模型中,对侧VPL刺激能够显著提高SNL侧足底的机械痛阈,而vl PAG刺激对SNL引发的触诱发痛没有影响。以上结果提示,PAG刺激对于急性痛以及慢性炎症痛有着较好的镇痛效果,而VPL刺激更适合慢性炎症痛和慢性神经病理痛的镇痛研究。     

电针对大鼠尾核痛兴奋,痛抑制神经元放电和甩尾反射的影响

浅麻醉ｗｉｓｔａｒ大鼠２５只,用Ｇ－６８０５型治疗仪电针刺激双侧“足三里”。以辐射热照尾部作为伤害性刺激,将痛兴奋神经元（ＰＥＮ）诱发放电频率减少,痛抑制神经元（ＰＩＮ）诱发放电频率增加和甩尾反射潜伏期（ＴＦＬ）延长作为镇痛效应,观察电针刺激“足三里”对尾核中ＰＥＮ、ＰＩＮ及ＴＦＬ的影响。结果表明,电针刺激“足三里”,尾核中ＰＥＮ、ＰＩＮ放电及ＴＦＬ均显示镇痛效应;电针对ＰＥＮ、ＰＩＮ放电及ＴＦＬ的影响高峰均出现在电针后即刻;电针前ＰＥＮ放电频率增加、ＰＩＮ放电频率减少与甩尾反射（ＴＦ）相伴行。放电变化发生在ＴＦ之前,结束在ＴＦ之后,ＰＥＮ、ＰＩＮ放电变化与ＴＦＬ呈高度正相关。镇痛作用高峰期ＰＥＮ、ＰＩＮ放电变化仍在ＴＦ前,结束在ＴＦ之后,两者呈高度正相关。提示尾核中的ＰＥＮ、ＰＩＮ是痛觉调节中枢的一部分,可能参与对ＴＦ的调节。     

大鼠杏仁核簇与痛觉调制的关系

目的：研究伤害性刺激对大鼠杏仁核簇中各亚核痛反应神经元电活动的影响。方法：用串电脉冲刺激坐骨神经作为伤害性刺激,用玻璃微电极引导神经元放电。结果：杏仁核簇中多个亚核均存在痛反应神经元。伤害性刺激使痛兴奋神经元(PEN)诱发放电频率增加;使痛抑制神经元(PIN)诱发放电频率降低,并出现放电频率极低现象;两类神经元电活动相互配合。腹腔注射吗啡(10mg／kg)可以对抗伤害性刺激对痛反应神经元的作用。结论：杏仁核簇中的部分亚核在感受、整合和传递痛觉信息方面起一定作用,是中枢神经系统控制和处理痛觉信息的一个组成部分。     

阻断炎症部位5-HT2A受体对大鼠完全弗氏佐剂诱发炎性痛和脊髓背角神经肽Y表达的作用

炎症时组织释放5-羟色胺(5-hydroxytryptamine,5-HT),对炎性痛觉过敏的产生起重要作用。但炎症组织5-HT2A受体在其中的意义尚不明确。本文旨在研究外周组织5-HT2A受体在慢性炎性痛中的作用。大鼠后足底注射完全弗氏佐剂(complete Freund’s adjuvant,CFA),在局部炎性部位给予选择性5-HT2A受体阻断剂酮色林,用行为学检测后足底对热和机械刺激的撤足反射,用免疫组织化学方法检查脊髓背角和背根神经节(dorsal root ganglion,DRG)中神经肽Y(neuropeptide Y,NPY)表达变化。结果显示,炎症局部给予酮色林(20、40、80μg)能剂量依赖性地抑制CFA诱发的热痛觉过敏;每日给予80μg酮色林,在第三天即完全翻转CFA引起的热痛觉过敏,以及部分地减轻触觉超敏。CFA诱发脊髓背角I~II层NPY表达增加,炎症组织局部注射酮色林能抑制脊髓背角NPY的表达增加,但不改变DRG中NPY的表达。这些结果表明:外周炎症组织5-HT2A受体激活参与慢性痛觉过敏的发生;阻断炎症部位5-HT2A受体能缓解疼痛,矫正与病理疼痛密切关联的脊髓背角细胞异常改变。因此,外周5-HT2A受体,有望成为治疗慢性炎性痛觉敏感性增高、不产生中枢神经系统副作用的药物靶点。     

低频和高频电针镇痛由脊髓水平不同类型的阿片受体介导:交叉耐受试验

以往的工作表明,给大鼠低频或高频电针在脊髓中分别释放出脑啡肽或强啡肽,产生镇痛效果。本工作用交叉耐受方法对此进行检验并进一步分析其受体机制。结果表明:(1) 给大鼠2Hz电针电针6h,镇痛作用逐渐降低导致耐受后,100Hz电针仍有明显的镇痛作用;100Hz耐受后,2Hz电针仍有效。说明低频和高频电针镇痛之间无明显的交叉耐受。(2) 100Hz电针耐受后,k激动剂强啡肽A(1—13)的脊髓镇痛作用明显减弱,而δ激动剂[(?)]enkephalin(DPDPE)仍保持明显的镇痛作用。(3) 2Hz电针耐受后,DPDPE的镇痛效果显著降低,而强啡肽A(1—13)的镇痛作用不受影响。根据以上的交叉耐受实验结果可以认为,脊髓中δ型阿片受体参与2Hz电针镇痛,而κ型阿片受体参与100Hz电针镇痛。     

急性神经损伤引起脊髓背角C-纤维诱发电位长时程增强

神经损伤引起神经病性疼痛,表现为持续性痛超敏和痛觉过敏。目前对神经病性疼痛的机制尚缺乏了解。我们以往的工作表明强直电刺激坐骨神经可引起脊髓背角C-纤维诱发电位的长时程增强(long-term potentiation,LTP),该LTP被认为是病理性疼痛的突触模型。本研究的目的在于探讨急性神经损伤是否能在完整动物的脊髓背角诱发出C-纤维诱发电位LTP。在以测试刺激(10～20V,0．5ms)电刺激坐骨神经的同时在脊髓背角用微电极记录C一纤维诱发电位。分别用强直刺激、剪断或夹捏坐骨神经诱导LTP。结果发现：(1)剪断或夹捏坐骨神经都可以诱导脊髓背角C-纤维诱发电位的LTP,该LTP可持续到实验结束(3～9h),在剪断神经前10min用利多卡因局部阻滞坐骨神经则可完全阻断LTP的产生;(2)神经损伤诱导的LTP可被NMDA受体阻断剂AP5所阻断;(3)用单次强直刺激引起LTP后,切断坐骨神经可使LTP的幅度进一步增大,而用多次强直电刺激使LTP饱和后,损伤神经则不能使LTP进一步增大。切断神经引起LTP后,强直电刺激也不能使LTP进一步增大。这些结果表明,急性神经损伤可以诱导脊髓背角C纤维诱发电位LTP,且切断神经能更有效地诱导LTP。该试验进一步支持我们的设想,即脊髓背角C-纤维诱发电位LTP可能在病理性疼痛的形成中起重要作用。     

HO/CO在甲醛炎性痛大鼠脊髓痛传导及痛觉过敏产生中的作用

目的:探讨血红素氧合酶/一氧化碳(HO/CO)在甲醛诱导的大鼠自发痛和痛觉过敏形成中的作用。方法:采用鞘内注射的方法,在甲醛炎性痛大鼠和正常大鼠分别给予HO抑制剂Znpp和HO激动剂Hemin;采用加权积分法对痛反应进行评分以代表痛反应程度;采用观察热辐射缩足潜伏期和机械刺激缩足反射阈值表示热和机械性痛觉过敏的程度。结果:Znpp各剂量组与单纯甲醛组相比,大鼠痛反应评分明显降低,且Znpp剂量越大,对大鼠痛反应的抑制作用越明显;与单纯甲醛组相比,Znpp各剂量组大鼠注射足热辐射缩足潜伏期和机械刺激缩足反射阈值均无明显变化,而非注射足热辐射缩足潜伏期和机械刺激缩足反射阈值均明显升高,且Znpp的剂量越大,这种改变越明显。正常大鼠鞘内注射HO的激动剂Hemin后,双侧足热辐射缩足潜伏期和机械刺激缩足反射阈值均明显降低。结论:鞘内给予HO抑制剂可明显抑制甲醛诱导的自发痛反应及热和机械性痛觉过敏程度;正常大鼠鞘内给予HO激动剂可诱发热和机械性痛觉过敏的产生,提示HO/CO系统参与脊髓伤害性信息的传导和痛觉过敏的形成过程。     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细