（^3H）二氢埃托啡与大鼠脑膜阿片受体的结合

目的：观察二氢埃托啡（ＤＨＥ）与阿片受体的结合情况。方法：采用放射配体受体结合实验，观察了（＾３Ｈ）ＤＨＥ与大鼠脑膜阿片受体的结合，结果：饱和实验显示（＾３Ｈ）ＤＨＥ的结合呈高亲和力单一位点，Ｋｄ＝０．１９±０．０５ｎｍｏｌ．Ｌ＾－１，Ｂｍａｘ＝１１５±２１ｐｍｏｌ／ｇｐｒｏｔｅｉｎ，动力学实验表明（＾３Ｈ）ＤＨＥ与阿片受体结合极快，解离很慢，ＮａＣｌ１００ｍｍｏｌ．Ｌ＾－１＋鸟苷三磷酸（ＧＴＰ）     

Modulation of NMDA receptor by huperzine A in rat cerebral cortex 1

目的：研究石杉碱甲（ＨｕｐＡ）对大脑皮层ＮＭＤＡ受体的影响．方法：１）用急性分离海马锥细胞全细胞记录研究ＨｕｐＡ对ＮＭＤＡ诱发电流的影响．２）用大脑皮层突触膜标本研究ＨｕｐＡ对［３Ｈ］Ｄｉｚ特异性结合的影响．结果：１）ＨｕｐＡ可逆地抑制ＮＭＤＡ诱发的电流反应（ＩＣ５０＝４５４μｍｏｌ·Ｌ－１）．２）在突触膜标本,ＨｕｐＡ抑制［３Ｈ］Ｄｉｚ的结合量（ＩＣ５０＝０５（０１－１９）μｍｏｌ·Ｌ－１,ｎ＝４）．３）Ｌ谷氨酸１０μｍｏｌ·Ｌ－１增加［３Ｈ］Ｄｉｚ结合量．加入Ｌ谷氨酸后,ＨｕｐＡ０００１－０１μｍｏｌ·Ｌ－１进一步增加结合量;ＨｕｐＡ１－３００μｍｏｌ·Ｌ－１则抑制结合量（ＩＣ５０＝１２３（５８－２６３）μｍｏｌ·Ｌ－１,ｎ＝５）．结论：ＨｕｐＡ在大脑皮层除了抑制乙酰胆碱酯酶外,还是ＮＭＤＡ受体拮抗剂     

赛庚啶对大鼠心肌细胞膜［~3H］－d－cis－硫氮卓酮结合部位的影响

苯并噻嗪类钙通道阻滞剂［３Ｈ］－ｄ－ｃｉｓ－硫氮酮能以一种特异和可饱和的方式与离体大鼠心肌细胞膜结合，其ＫＤ值和Ｂｍａｘ分别为８４ｎｍｏｌ·Ｌ－１和０．２７９ｐｍｏｌ·ｍｇｐｒｏｔｅｉｎ－１。非标记的硫氮酮和赛庚啶均能完全抑制这种结合，其Ｋｉ值分别为１０２ｎｍｏｌＬ－１和５．５ｕｍｏｌ·Ｌ－１。上述结果证实在大鼠心肌细胞膜上也存有［３Ｈ］－硫氮酮受体，同时还提示赛马庚啶对心肌细胞膜的钙通道阻滞作用可能与作用于心肌细胞膜［３Ｈ］硫氮酮受体有关。     

BN3C对大鼠心肌细胞膜二氢吡啶受体的作用

目的研究ＢＮ３Ｃ对大鼠心肌细胞膜二氢吡啶受体的作用。方法放射性配基结合实验。结果［３Ｈ］ＰＮ２００－１１０在０．１～３．２ｎｍｏｌ·Ｌ－１范围与大鼠心肌细胞膜的特异性结合是可饱和的,其ＫＤ和Ｂｍａｘ值分别为０．８２ｎｍｏｌ·Ｌ－１和１０９．７２ｐｍｏｌ·ｇ－１Ｐｒｏ－１。当有１×１０－９ｍｏｌ·Ｌ－１ＢＮ３Ｃ存在时,其ＫＤ和Ｂｍａｘ值分别为２．０１ｎｍｏｌ·Ｌ－１和１１５．３１ｐｍｏｌ·ｇ－１Ｐｒｏ－１。ＢＮ３Ｃ、拉西地平、硝苯吡啶竞争性抑制［３Ｈ］ＰＮ２００－１１０与大鼠心肌细胞膜结合的ＩＣ５０分别为２．４×１０－９,１．５×１０－８,１．９×１０－８ｎｍｏｌ·Ｌ－１;ＫＩ值分别为１．４９,９．２２和１１．６４ｎｍｏｌ·Ｌ－１。结论ＢＮ３Ｃ可特异性地作用于［３Ｈ］ＰＮ２００－１１０的结合部位,竞争性地抑制［３Ｈ］ＰＮ２００－１１０与大鼠心肌细胞膜的结合;ＢＮ３Ｃ与受体的亲和力强于拉西地平和硝苯吡啶。     

Binding properties of C-truncated delta opioid receptors

目的：研究δ阿片受体Ｃ末端在受体结合配体的亲和力及选择性中的作用．方法：在中国苍鼠卵巢细胞（ＣＨＯ细胞）中分别稳定表达Ｃ末端截短３１个氨基酸残基及野生型δ阿片受体，用受体结合分析法研究表达产物与配体的结合特征．结果：表达得到典型突变受体克隆ＣＨＯＴ及野生型受体克隆ＣＨＯＷ．ＣＨＯＴ结合［３Ｈ］ｄｉｐｒｅｎｏｒｐｈｉｎｅ（Ｄｉｐ）及［３Ｈ］［ＤＡｌａ２，ＤＬｅｕ５］ｅｎｋｅｐｈａｌｉｎ（ＤＡＤＬＥ）的Ｋｄ值与ＣＨＯＷ一致，δ选择性激动剂对二者与［３Ｈ］Ｄｉｐ的结合均有很强的抑制作用，且Ｋｉ相似；而μ及κ选择性激动剂则对二者均无抑制作用．结论：δ阿片受体的Ｃ末端与受体结合配体的亲和力及选择性无关．     

兔小脑μ阿片受体的特性及其分布

应用放射配体结合试验和放射自显影研究了［＾３Ｈ］羟甲芬太尼（［＾３Ｈ］ＯＭＦ），［＾３Ｈ］埃托啡（［＾３Ｈ］Ｅｔｏ），［＾３Ｈ］Ｕ６９５９３和［＾３Ｈ］ＤＰＤＰＥ与兔小脑的结合特性。［＾３］ＯＭＦ和［＾３Ｈ］Ｅｔｏ与兔小脑有一呈饱和性的单位点的结合，它们的Ｋｄ分别为２．２±１．３和１．０±０．４ｎｍｏｌ·Ｌ＾－１，Ｂｍａｘ分别为６９±１３和１６±６ｆｍｏｌ／ｍｇ蛋白。［＾３Ｈ］Ｕ６９５９３和［＾３     

NAD-and NADP-dependent 11β-hydroxysteroid dehydrogenase isoforms in guinea pig kidney with gossypol inhibition

探讨棉酚诱发低钾血症机制．方法：从豚鼠肾脏皮质制备１１βＯＨＳＤ，反相高效液相测定该酶活性．结果：依赖辅酶Ｉ的１１βＯＨＳＤ的Ｖｍａｘ＝０６４ｍｍｏｌ·ｈ－１／ｇｐｒｏｔｅｉｎ，Ｋｍ＝００７μｍｏｌ；依赖辅酶ＩＩ的１１βＯＨＳＤ的Ｖｍａｘ＝１７５ｍｍｏｌ·ｈ－１／ｇｐｒｏｔｅｉｎ，Ｋｍ＝０２１μｍｏｌ．棉酚对它们的抑制有显著差异，ＩＣ５０（９５％可信限）前者为５０２（４８３－５２０）μｍｏｌ，后者为１１４３（１０９８－１１８８）μｍｏｌ，抑制常数Ｋｉ分别为９６ｍｍｏｌ·Ｌ－１和３４０ｍｍｏｌ·Ｌ－１．结论：抑制依赖辅酶Ｉ的１１βＯＨＳＤ是棉酚诱发低钾血症的更主要的生理因素．     

槲皮素对大鼠大脑皮质细胞膜α_2－肾上腺素能受体的影响

用３Ｈ－可乐定分析大鼠大脑皮质细胞膜α２－肾上腺素能受体的特征，研究槲皮素对３Ｈ－可乐定结合的影响。３Ｈ－可乐定与大鼠大脑皮质细胞膜的结合是快速（Ｋ１：０．０２７Ｌ·ｎｍｏｌ－１·ｍｉｎ－１）、可逆（Ｋ２：０．１０４ｍｉｎ－１）的，有高度亲和力（ＫＤ：５．８７±１．１３ｎｍｏｌ·Ｌ－１）和可饱和性（Ｂｍａｘ：１６０±１０ｐｍｏｌ·ｇ－１，ｐｒ）。ｌ－可乐定、ｌ－肾上腺素、ｌ－去甲肾上腺素和ｌ－异丙肾上腺素等药物抑制３Ｈ－可乐定结合的效能顺序表明，大鼠大脑皮质细胞膜上３Ｈ－可乐定结合点为α２－肾上腺素能受体。１ｎｍｏｌ·Ｌ－１～１ｍｍｏｌ·Ｌ－１槲皮素竞争抑制３Ｈ－可乐定与大鼠大脑皮质细胞膜α２－肾上腺素能受体结合，Ｋｉ值为５．７３±１．５８μｍｏｌ·Ｌ－１。     

Kinetic properties of nicotinic receptors in cultured rat sympathetic neurons from superior cervical ganglia

目的：研究培养的新生大鼠颈上神经节交感神经元烟碱受体的动力学特性．方法：膜片箝技术的全细胞记录方法，记录不同浓度烟碱诱发的电流，使用Ｃｌａｒｋ方程对烟碱作用的量效曲线进行拟合．结果：１０，２０，４０，８０和１６０μｍｏｌ·Ｌ－１烟碱诱发电流的幅度分别为：０９１±００８，１５６±０１４，２５３±０２７，３９３±０４６和４５７±０５５ｎＡ（ｎ＝１５），经Ｃｌａｒｋ方程拟合，得到Ｈ＝１０９７，Ｅｍａｘ＝５９５８ｎＡ，Ｋ＝７３０６１μｍｏｌ·Ｌ－１，将Ｈ＝１时拟合得到的Ｅｍａｘ（６５１３ｎＡ）和Ｋ值（６１４５７μｍｏｌ·Ｌ－１）代入Ｃｌａｒｋ方程，所计算出的理论值与相应浓度烟碱诱发电流的实测值基本相符．结论：烟碱与交感神经元烟碱受体作用的动力学特性符合一个作用位点的反应模型．     

金仓鼠脑内的 kappa 受体

目的：研究〔３Ｈ〕依托啡与金仓鼠脑内ｋａｐｐａ受体结合及其在脑内分布的特性。方法：用受体结合和药物的竞争抑制试验研究〔３Ｈ〕依托啡与金仓鼠脑匀浆中ｋａｐｐａ受体结合。结果：〔３Ｈ〕依托啡与金仓鼠脑匀浆中ｋａｐｐａ受体结合的Ｋｄ值和Ｂｍａｘ值分别为０．５２ｎｍｏｌ·Ｌ－１和３４．０ｐｍｏｌ·ｇ－１蛋白。５μｍｏｌ·Ｌ－１（Ｄ－Ａｌａ２，Ｄ－Ｌｅｕ５）脑啡肽可完全阻断〔３Ｈ〕依托啡与ｋａｐｐａ受体的结合。该结合易被苯吗啡烷类及奥列巴文类药物取代，而不易被强啡肽Ａ（１－１３）取代。金仓鼠脑内ｋａｐｐａ受体存在不同的局部分布，纹状体和中脑的密度较高（Ｋｄ和Ｂｍａｘ值为０．４８±０．０２１ｎｍｏｌ·Ｌ－１和２６．６±２．１ｐｍｏｌ·ｇ－１蛋白；０．４１±０．０１５ｎｍｏｌ·Ｌ－１和２４．９±０．３６ｐｍｏｌ·ｇ－１蛋白），大脑皮层的密度较低（Ｋｄ和Ｂｍａｘ值为０．４２±０．０２ｎｍｏｌ·Ｌ－１和１０．５±０．８５ｐｍｏｌ·ｇ－１蛋白）。结论：金仓鼠脑内有优势的ｋａｐｐａ受体，它不同于经典的ｋａｐｐａ受体，可能属于ｋａｐ－ｐａ２受体。纹状体和中脑的ｋａｐｐａ受体分布密度最高。     

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.