氯代斯阔任对多巴胺受体的作用

目的:比较四氢原小檗碱同类物(THPB)和氢化苄基-四氢异喹啉类(HBTI)两类化合物对DA受体的作用强度,从而找出对DA受体作用更有效的化合物。方法:用小牛纹状体膜蛋白对D_1和D_2受体进行放射受体结合分析并进行大鼠行为实验。结果:(±)12-氯代斯阔任(CSL)对D_1和D_2受体的亲和力分别为13和51nmol·L~(-1),与先导化合物左旋千金藤立定[(-)stepholidine,SPD]在同一水平,动物行为实验表明它对DA受体有阻滞作用,但在超敏条件下,出现激动作用,这些特点与SPD的作用类似。结论:CSL是目前THPB中对DA受体作用最强者,与SPD类似是对DA受体阻滞剂兼有激动作用。     

多巴胺D1受体在Sf9昆虫细胞中的表达及左旋氯代斯阔任对重组D1受体的激动作用

目的:在Sf9昆虫细胞中表达D_1受体,并研究左旋氯代斯阔任对重组D_1受体的激动作用。方法:构建含D_1受体cDNA的重组杆状病毒,以其感染Sf9昆虫细胞得到D_1受体表达。[~3H]SCH23390受体结合检测重组D_1受体的药理特性。[~3H]SCH23390受体结合和cAMP测定实验检测左旋氯代斯阔任对重组D_1受体的激动作用。结果:在Sf9昆虫细胞中成功表达D_1受体,[~3H]SCH23390与重组D_1受体最大结合量(B_(max))为(0.94±0.06)nmol/g蛋白,[~3H]SCH23390与重组D_1受体的结合解离常数(K_d)为(1.9±0.3)nmol/L,其药理特性与小牛纹状体脑匀浆所得结果一致。左旋氯代斯阔任对重组D_1受体有高亲和力,解离常数K_i为(6.3±1.4)nmol/L;并剂量依赖地引起胞内cAMP增加,EC_(50)为0.72μmol/L(95％可信限为0.67-0.77μmol/L),表现出D_1激动作用。结论:在杆状病毒/昆虫细胞Sf9中,成功建立了D_1受体异源表达系统。在细胞分子水平,直接证实了左旋氯代斯阔任对D_1受体的激动作用。     

左旋千金藤立定和12-氯斯阔任旋光异构体对黑质多巴胺神经元放电活动的比较(英文)

目的:比较左旋千金藤立定((-)-stepholidine,(-)-SPD)和12-氯斯阔任(12-chloroscoulerine,CSL)对黑质(substantia nigra,SN)多巴胺(DA)神经元放电的影响。方法:麻痹大鼠上的胞外单单位记录。结果:在大鼠,(-)-SPD,(-)-,(±)-和( )-CSL减弱iv 10μg·kg~(-1)阿朴吗啡引起的放电抑制。ED_(50)值分别为15.1(11.9—19.4),7.8(7.0—8.7),12.6(2.0—17.9)μg·kg~(-1)和2.9(2.6—3.3)mg·kg~(-1)。(-)-CSL比(-)-SPD强1倍,比( )-CSL强371倍。在利血平化大鼠,(-)-SPD,(-)-,(±)-,和( )-CSL减弱4mg·kg~(-1)SKF-38393引起的放电抑制。ED_(50)值为0.53(0.51—0.55),0.51(0.43—0.60),1.2(0.7—2.0)和5.9(4.9—7.1)mg·kg~(-1)。(-)-CSL的强度与(-)-SPD相似,比( )-CSL强11倍。结论:(-)-SPD和CSL是D_1/D_2混合性阻滞剂。(-)-CSL最强,( )-CSL最弱。     

多巴胺诱导大鼠海马脑片Ca~(2 )-钙调素依赖性蛋白激酶Ⅱ活性的抑制作用(英文)

目的:研究多巴胺(DA)对大鼠海马脑片Ca~(2 )-钙调素依赖性蛋白激酶Ⅱ(CCDPK Ⅱ)活性的影响。方法:采用大鼠海马脑片体外培养模型,以~(32)P-掺入法测定CCDPK Ⅱ的活性。结果:外源性DA可显著降低大鼠海马脑片CCDPK Ⅱ活性,并有一定的浓度依赖性和时间依赖性。去除胞外的Ca~(2 )对不同浓度DA诱导的CCDPK Ⅱ活性抑制有部分或完全保护作用。阿扑吗啡(非特异性DA受体激动剂)、SKF38393(特异性D_1样DA受体激动剂)和喹吡罗(特异性D_2样DA受体激动剂)均可显著降低CCDPK Ⅱ的活性。Sch-23390(特异性D_1样DA受体拮抗剂)和多潘立酮(特异性D_2样DA受体拮抗剂)均可拮抗DA所诱导的酶活性抑制。结论:DA抑制海马CCDPK Ⅱ的活性,其作用机制与D_1样和D_2样受体以及胞外Ca~(2 )的内流有关。     

多巴胺对小鼠神经母细胞瘤和大鼠神经胶质瘤的杂交(NG108)细胞在体外的毒性(英文)

目的:研究多巴胺(DA)对小鼠神经母细胞瘤和大鼠神经胶质瘤的杂交细胞NG108的毒性.方法:用MTT法测定NG108细胞的活性.结果:当DA浓度在100 μmol L~(-1)时对NG108细胞有毒性作用.这时的细胞活性仅为对照的1/4左右.DA受体拮抗剂舒必利和Sch-23390不能阻断DA毒性,表明DA对NG108细胞的毒性作用不是由DA受体介导的.DA(125 μmol L~(-1))的毒性作用能被过氧化氢酶(50 kU L~(-1))、超氧化物歧化酶(50kU L~(-1))和维生素C(200 μmol L~(-1))抑制.它们分别能使NG108细胞的活性由DA单独作用时的25.9±11.0％上升到74.8±4.4％、72.3±4.5％和71.4±2.3％.结论:DA对NG108细胞的毒性作用是由DA氧化代谢产生的有毒产物如过氧化氢引起的.     

mTOR信号通路介导姜黄素抗抑郁作用机制

目的探讨mTOR信号通路介导姜黄素抗抑郁作用机制。方法建立皮质酮损伤SH-SY5Y细胞模型。通过CCK-8法检测姜黄素对皮质酮诱导SH-SY5Y细胞保护作用。建立小鼠强迫游泳和悬尾急性抑郁模型,将40只雄性ICR小鼠随机分成4组,分别为生理盐水(侧脑室注射生理盐水,ICV)+溶剂(灌胃,ig)组、生理盐水(ICV)+姜黄素(50 mg·kg-1,ig)组、雷帕霉素(150 nmol·L~(-1),ICV)+溶剂(ig)组、雷帕霉素(150 nmol·L~(-1),ICV)+姜黄素(50 mg·kg~(-1),ig)组。姜黄素给药前30 min预先侧脑室注射雷帕霉素,给药30 min后进行行为学测试。结果给予姜黄素共培养能够明显提高皮质酮损伤SH-SY5Y细胞存活率(1 nmol·L~(-1),P<0.01;0.5 nmol·L~(-1),P<0.01;0.25 nmol·L~(-1),P<0.05),而雷帕霉素能够阻断姜黄素的保护作用(P<0.05)。姜黄素能够明显降低小鼠强迫游泳不动时间(P<0.01)和悬尾不动时间(P<0.05),而预先侧脑室注射雷帕霉素后,姜黄素降低小鼠强迫游泳不动时间(P<0.01)和悬尾不动时间(P<0.05)的作用被降低。结论姜黄素具有明显的抗抑郁作用,且其抗抑郁作用可能与激动mTOR信号通路有关。     

盐酸吲满氨酯及依色林对胆碱酯酶的抑制作用

用微量二硫-双-硝基苯甲酸(DTNB)法测定胆碱酯酶(ChE)活力,比较了盐酸吲满氨酯(TMDMC)与依色林抑制ChE的作用,对于电鳐AChE依色林表现为竞争性抑制,K_i=0.115 μmol·L~1,TMDMC表现为竞争与非竞争混合性抑制,K_i=3.870μmol·L~(-1),K_i=16.321μmol·L~(-1)依色林和TMDMC抑制小鼠脑匀浆ChE活力的IC_(50)分别为1.78和5.07μmol·L~1、抑制小鼠全血ChE活力的IC_(50)分别为19.52和3.60μmol·L~1,说明TMDMC与依色林虽属同类化合物,但它们的抑酶类型和对真,假性ChE的抑制强度是不同的。     

放射配体结合法鉴定小鼠子宫平滑肌β肾上腺素受体(英文)

用放射配体结合法鉴定小鼠子宫平滑肌β肾上腺素受体,结果显示l-去甲肾上腺(NE),dl-普萘洛尔(Pro),d-噻吗洛尔(d-Tim),l-Tim的IC_(50)依次为171±10,10.3±4.3,6.5±2.1·0.40±0.23 nmol·L~(-1);K_1依次为113±6,6.3±2.8,4.0±1.3,0.25±0.14nmol·L~(-1),亲合力顺序为l-Tim>d-Tim>dl-Pro>l-NE,阿替洛尔不能抑制[~3H]二氢阿普丙洛尔的结合,提示小鼠子宫平滑肌具有β_2肾上腺素受体。     

胍丁胺对异丙肾上腺素诱发豚鼠乳头状肌后除极的影响(英文)

目的:研究胍丁胺(Agm)对异丙肾上腺素(Iso)诱发豚鼠乳头状肌早发和晚发后除极(EAD和DAD)的影响及其作用机制。方法:细胞内玻璃微电极技术。结果:(1)Agm明显抑制Iso诱发的EAD和DAD;(2)预先应用NOS抑制剂L-NAME0.5mmol·L~(-1),不能影响Agm1.0mmol·L~(-1)对Iso 20nmol·L~(-1)诱发EAD和DAD的抑制作用;(3)预先应用咪唑啉受体(IR)和肾上腺素能α_2受体(α_2-AR)拮抗剂idazoxan 0.1mmol·L~(-1)则可阻断这种作用。结论:Agm对Iso诱发EAD和DAD的抑制作用由α_2-AR和/或IR介导,并与钙内流减少有关。     

左旋千金藤立定和DA受体激动剂对6-OHDA损毁大鼠旋转行为和基底核神经元放电的作用部位(英文)

目的:确定l-SPD在基底神经核的作用部位。方法:6-OHDA损毁大鼠单侧黑质致密区(SNC),核团内微注或微电泳给予l-SPD或DA激动剂,作旋转实验和神经元放电记录。结果:1)大鼠纹状体损毁侧DA免疫反应物减少。2)新纹状体或黑质网质区(SNR)内微注DA激动剂Apo(D_1/D_2),SK＆F38393(D_1)或SPD引起大鼠强烈旋转,而微注Ly171555(D_2)于SNR或DA激动剂和l-SPD于苍白球(GP)均不引起旋转。卡英酸进一步损毁GP或脚间核(EP),DA激动剂或l-SPD诱发大鼠旋转显著下降。3)微电泳Apo或SPD引起SNR神经元放电,但对GP神经元无效。结论:l-SPD诱发大鼠旋转和神经元放电由D_1受体介导,基底核新纹状体和SNR是其作用部位,而不是GP。通过SNR的直接环路在旋转行为中起重要作用。     

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.

     

Pharmacological treatment of COVID-19: an opinion paper

The precocity and efficacy of the vaccines developed so far against COVID-19 has been the most significant and saving advance against the pandemic. The development of vaccines has not prevented, during the whole period of the pandemic, the constant search for therapeutic medicines, both among existing drugs with different indications and in the development of new drugs. The Scientific Committee of the COVID-19 of the Illustrious College of Physicians of Madrid wanted to offer an early, simplified and critical approach to these new drugs, to new developments in immunotherapy and to what has been learned from the immune response modulators already known and which have proven effective against the virus, in order to help understand the current situation.     

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.     

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.     

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.