烟碱对大脑皮层毒蕈碱型受体与其激动剂和拮抗剂结合的调节

目的：研究烟碱对脑Ｍ受体结合性能的调节作用。 方法：测定烟碱对脑Ｍ受体与其激动剂［＾３Ｈ］氧颤莫林－Ｍ和拮抗ｌ－［＾３Ｈ］奎纽定二苯羟乙酸（ＱＮＢ）结合的影响。 结果：大鼠大脑皮层膜标本经烟碱预处理后，Ｍ受体与［＾３Ｈ］氧颤莫林－Ｍ特异性结合的平衡解离常数降低，最大结合量不变；Ｍ受体与ｌ－［＾３Ｈ］ＱＮＢ特异性结合的平衡解离常数增高，最大结合量也不变。烟碱对Ｍ受体与ｌ－［＾３Ｈ］ＱＮＢ特异性结合的     

M胆碱能药物对家兔虹膜M受体亚型的作用

目的比较不同的Ｍ受体激动剂或Ｍ受体亚型拮抗剂对［３Ｈ］ ＱＮＢ与家兔虹膜中Ｍ受体竞争结合的影响。方法放射性配基受体结合试验。结果Ｍ受体激动剂和Ｍ受体亚型拮抗剂均可抑制［３Ｈ］ ＱＮＢ与家兔虹膜中Ｍ受体的结合,呈剂量依赖性。激动剂对其抑制的强度依次为：丁公藤碱＞乙酰奎宁＞毛果芸香碱,亚型拮抗剂对其抑制的强度依次为：４ ＤＡＭＰ＞ＰＺ＞ｇａｌａｍｉｎｅ。结论ｍ３受体亚型在兔缩瞳的药理作用中起重要作用。     

M胆碱能药物对家兔虹膜M受体亚型的作用

目的比较不同的Ｍ受体激动剂或Ｍ受体亚型拮抗剂对［３Ｈ］ＱＮＢ与家兔虹膜中Ｍ受体竞争结合的影响。方法放射性配基受体结合试验。结果Ｍ受体激动剂和Ｍ受体亚型拮抗剂均可抑制［３Ｈ］ＱＮＢ与家兔虹膜中Ｍ受体的结合,呈剂量依赖性。激动剂对其抑制的强度依次为：丁公藤碱＞乙酰奎宁＞毛果芸香碱,亚型拮抗剂对其抑制的强度依次为：４ＤＡＭＰ＞ＰＺ＞ｇａｌａｍｉｎｅ。结论ｍ３受体亚型在兔缩瞳的药理作用中起重要作用。     

新抗胆碱药[3H]三环哌酯对人脑M受体的作用

用放射配体受体结合试验法,研究了新化合物三环哌酯与人大脑皮质M受体的结合特性,并与QNB作了比较。饱和实验结果显示,[³H]三环哌酯的结合参数与[³H]QNB相近,两种配体的作用均符合单位点模型。竞争性抑制实验结果表明二者作用强度相当。[³H]三环哌酯的结合和解离速率常数均较[³H]QNB大,且其与皮质M受体的解离受季铵酚的变构调节,结果提示,两种配体与M受体有一些不同的结合特性,在M受体研究中,[³H]三环哌酯可以作为[³H]QNB的补充工具。     

遗传性癫痫易感大鼠脑内NMDA受体功能的研究

Ｎ－甲基－Ｄ－天门冬氨酸（ＮＭＤＡ）受体与癫痫的产生密切相关，我们以［３Ｈ］ＭＫ－８０１在ＮＭＤＡ受体激动剂作用下与突触膜结合情况，检测了遗传性癫痫易感大鼠Ｐ７７ＰＭＣ的ＮＭＤＡ受体功能。结果显示：１０－６ｍｏｌ·Ｌ－１谷氨酸或１０－６ｍｏｌ·Ｌ－１谷氨酸加１０－６ｍｏｌ·Ｌ－１甘氨酸可促进Ｐ７７ＰＭＣ大鼠大脑皮层、海马对［３Ｈ］ＭＫ－８０１的结合，并显著高于对照。一些抗癌药及生物制剂可降低或促进［３Ｈ］ＭＫ－８０１的结合。提示ＮＭＤＡ受体活性增高是遗传性癫痫易感大鼠惊厥产生的重要因素，以及抗病药的可能作用途径。     

［~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）５０μｍｏｌ·Ｌ－１可使［３Ｈ］ＤＨＥ的Ｋｄ值提高为７８７ｎｍｏｌ·Ｌ－１，Ｂｍａｘ值不变．激动剂和拮抗剂的竞争抑制实验均表明［３Ｈ］ＤＨＥ与μ阿片受体的亲和力大于δ和κ受体．结论：ＤＨＥ对μ阿片受体具有一定选择性．     

大脑皮层~3H-三环哌酯结合位点的药理学特征

目的研究大脑皮层３Ｈ－三环哌酯（３Ｈ－ＴＣＰＮ）结合位点的药理学特征。方法在大鼠大脑皮层匀浆标本上，测定３Ｈ－ＴＣＰＮ的特异性结合位点以及药物对它的影响。结果３Ｈ－ＴＣＰＮ与大鼠大脑皮层膜标本具有特异性结合，其饱和性结合的参数与３Ｈ－ＱＮＢ的饱和性结合参数相似，其中，Ｋｄ值为０．４０ｎｍｏｌ·Ｌ－１，Ｂｍａｘ值为１２５８ｐｍｏｌ·ｇ－１。３Ｈ－ＴＣＰＮ特异性结合位点中，被阿托品取代的Ｍ受体部分占７０％，不被阿托品取代的称Ｘ位点部分占３０％；Ｘ结合位点既不为Ｎ受体激动剂烟碱和非竞争拮抗剂美加明所占据，也不为ＧＡＢＡ受体拮抗剂苦味毒素，甘氨酸受体拮抗剂士的宁和胆碱酯酶抑制剂毒扁豆碱所占据。结论大鼠大脑皮层３Ｈ－ＴＣＰＮ特异性结合位点中，７０％为Ｍ受体，其它位点的药理学性质有待进一步研究     

Agonistic effects of berberine hydrochloride on muscarinic receptors 1

用大鼠离体胸主动脉环和豚鼠离体气管条功能实验及放射配基受体结合实验研究盐酸小檗碱（Ｂｅｒ）对组织毒蕈碱受体（Ｍ受体）的作用．结果表明较高浓度的Ｂｅｒ（≥２０μｍｏｌ·Ｌ－１）对有内皮的动脉环具直接舒张作用;在去内皮或阻断Ｍ受体后,其舒张作用被完全抑制．Ｂｅｒ使豚鼠离体气管条产生浓度依赖性收缩,此作用可被阿托品拮抗,其ｐＡ２值为９．８．放射配基受体结合实验显示,Ｂｅｒ对大鼠的唾液腺,大脑皮质和心脏Ｍ受体均有中度亲和力,且使［３Ｈ］－二苯羟乙酸奎宁酯（ＱＮＢ）与３种组织Ｍ受体结合的Ｋｄ值增大,最大结合量不变．其Ｋｉ值分别为（７．６±１．３）,（１．６±０．９）和（０．５８±０．０７）μｍｏｌ·Ｌ－１．结果提示,Ｂｅｒ有Ｍ受体激动作用．     

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     

莨菪类生物碱对18,28及38日龄小鼠的行为和记忆障碍作用

比较阿托品（Ａｔｒ），东莨菪碱（Ｓｃｏ），樟柳碱（ＡＴ３）和山莨菪碱（Ａｎｉ）对小鼠行为及记忆损伤作用。方法：行为和记忆实验用开阔和回避反应法。脑Ｍ受体用［＾３Ｈ］ＱＮＢ测定。结果：Ａｔｒ，Ｓｃｏ和ＡＴ３增加小鼠走动行为２６％－４２％，降低站忆。４个药物均能妨碍回避反应。小鼠１８日龄额叶皮层和海马［＾３Ｈ］ＱＮＢ结合位点数少于３８日龄７％－２３％。结论：１）莨菪类生物碱对小鼠行为和记忆障碍的作用随     

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.     

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.     

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.