蝙蝠葛碱对豚鼠心室肌细胞L型钙电流阻断作用

目的：研究蝙蝠葛碱对豚鼠心室肌细胞Ｌ型钙电流的阻断作用及其特性。方法：利用全细胞记录方法，记录单个豚鼠心室肌细胞Ｌ型钙电流。结果：蝙蝠葛碱１，１０，１００μｍｏｌ·Ｌ＾－１可使钙电流分别减少１５．２％±２．２％，４１％±５％，８２％±８％。冲洗后，可使钙电流部分恢复，蝙蝠葛碱具有浓度依赖性阻断钙电流的作用。在刺激频率３Ｈｚ与１Ｈｚ，其阻断钙电流的程序相似。结论：蝙蝠葛碱具有阻断Ｌ型钙电流的作用。     

Effects of dauricine,quinidine,and sotalol on action potential duration of papillary muscles in vitro

目的：观察蝙蝠葛碱对豚鼠乳头状肌的动作电位是否具有使用依赖性特征，并与奎尼丁、索他洛尔作平行比较．方法：利用细胞内微电极技术记录豚鼠乳头状肌跨膜动作电位．结果：蝙蝠葛碱２０μｍｏｌ·Ｌ－１能明显延长乳头状肌跨膜动作电位时程，在刺激周长为２００，３００，４００，６００，８００，１０００，２０００ｍｓ时，其延长动作电位时程的百分率分别为２２±８，１１±６，９±５，７±５，６±３，４３±２８，４５±２８，蝙蝠葛碱延长动作电位时程作用于刺激周期较短时作用明显，呈使用依赖性特征．而奎尼丁１μｍｏｌ·Ｌ－１和索他洛尔１０μｍｏｌ·Ｌ－１延长动作电位时程作用随刺激周期延长而增强，呈现逆向使用依赖性特征．结论：蝙蝠葛碱使用依赖性延长豚鼠乳头状肌动作电位时程．     

Blocking effects of phentolamine on L-type calcium current and ATP-sensitive potassium current in guinea pig ventricular myocytes

目的：研究酚妥拉明对豚鼠心室肌细胞Ｌ型钙电流及ＡＴＰ敏感钾电流的作用．方法：用膜片钳的全细胞记录方式观察钙电流和ＡＴＰ敏感钾电流．结果：酚妥拉明５，２５和１００μｍｏｌ·Ｌ－１对钙电流呈浓度依赖性和非电压依赖性的抑制作用，抑制率分别为１７％，２３％和３０％，而对电流电压关系没有影响．这一抑制作用与酚妥拉明对α１和α２受体的作用无关．酚妥拉明１００μｍｏｌ·Ｌ－１可显著抑制ＤＮＰ诱导产生的ＡＴＰ敏感钾电流，抑制率为７５％．结论：酚妥拉明显著抑制豚鼠心室肌细胞Ｌ型钙电流和ＡＴＰ敏感钾电流．     

Effects of berberine on L-and T-type calcium channels in guinea pig ventricular myocytes

目的：研究小檗碱（Ｂｅｒ）对心室肌细胞钙通道的影响．方法：全细胞膜片箝技术．结果：Ｂｅｒ（１０，３０μｍｏｌ·Ｌ－１）使豚鼠心室肌细胞Ｌ型钙流由１４００±２４７ｐＡ分别减至９７８±２０４ｐＡ及６１７±２３ｐＡ（ｎ＝５，Ｐ＜００５），抑制效应呈浓度依赖及非频率依赖，其电流－电压曲线的峰值下降．Ｂｅｒ（１０μｍｏｌ·Ｌ－１）使Ｌ型钙流失活曲线的最大半激活电压由－２７８ｍＶ变为－３４２ｍＶ，斜率因子由９２２变为１３０３，对激活曲线无影响．Ｂｅｒ（１０，３０μｍｏｌ·Ｌ－１）使Ｔ型钙流峰值由加药前的１５４±８０ｐＡ降至１０１±７８ｐＡ及４８±４５ｐＡ（ｎ＝８，Ｐ＜００５）．结论：Ｂｅｒ对Ｌ和Ｔ型钙通道均有抑制作用．     

蝙蝠葛碱对豚鼠心室肌细胞钾电流的阻断作用(英文)

目的:研究蝙蝠葛碱对豚鼠心室肌细胞快激活(I_(Kr))和慢激活(I_(Ks))延迟整流钾电流及内向整流钾电流(I_(K1))的作用。方法:酶解法制备单个心室肌细胞。电压箝制方式下全细胞记录豚鼠单个心室肌细胞钾通道电流。结果:蝙蝠葛碱1-100μmol·L~(-1)浓度依赖性阻断I_(Ks),I_(Ks-tail)[IC_(50)=33(95 ％可信限:24-46)μmol·L~(-1)]及I_(Kr),I_(Kr-tail)[IC_(50))=16 (95％可信限:13-22)μmol·L~(-1)]。对I_(Ks-tail),I_(Kr-tail)的去激活过程无明显影响,给药前的时间常数分别为(92±18)ms和(140±38)ms,给药后分别为(84±16)ms和(130±26)ms(P>0.05)。蝙蝠葛碱对I_(Ks)的抑制作用具有电压依赖性。 蝙蝠葛碱20μmol·L~(-1)对I_(K1)的内向部分具有阻断作用。结论:蝙蝠葛碱对I_(Kr)和I_(Ks)具有阻断作用,但不影响此两种成分的去激活过程. 蝙蝠葛碱同时具有阻断I_(K1)的作用。     

Effects of dauricine on early afterdepolarizations and triggered activity induced by quinidine in guinea pig papillary muscle

用标准微电极技术观察了中药蝙蝠葛的有效成分蝙蝠葛碱对奎尼丁诱发的豚鼠乳头肌早后去极化及触发活动的影响．结果表明，奎尼丁２μｍｏｌ·Ｌ－１能诱发豚鼠乳头肌早后去极化及触发活动，早后去极化的发生率为８／２０，幅值为１３．４±２．６ｍＶ，起始电位为－４２±５ｍＶ，触发活动的发生率为２／２０．蝙蝠葛碱２０μｍｏｌ·Ｌ－１能明显抑制奎尼丁诱发的早后去极化及触发活动，早后去极化的发生率为４／２０，幅值为７．３±１．１ｍＶ，无触发活动．结果提示蝙蝠葛碱具有抗早后去极化所致心律失常．     

蝙蝠葛苏林碱对心肌细胞浆Ca~（2＋）活度的影响

目的：探讨蝙蝠葛苏林碱（ＤＳ）对迟后除极的作用．方法：采用Ｃａ２＋敏感性微电极技术．结果：毒毛旋花甙Ｇ（Ｓｔｒ，３μｍｏｌ·Ｌ－１）使豚鼠心室乳头肌细胞浆Ｃａ２＋活度（ɑｉＣａ）增加０１９±０１１μｍｏｌ·Ｌ－１，在出现迟后除极和触发活动（ＴＡ）时又分别增加１４８±０５５和４９６±１８１μｍｏｌ·Ｌ－１．标本经ＤＳ作用后．Ｓｔｒ不再引起ɑｉＣａ增高和ＴＡ．ＤＳ抑制无Ｎａ＋和咖啡因引起的狗心肌ɑｉＣａ增加．结论：ＤＳ可阻止Ｃａ２＋跨膜入胞浆而防止ɑｉＣａ增高起抗ＴＡ作用．     

粉防己碱对分离的豚鼠心室肌单细胞动作电位及钙通道电流的影响

用自行研制的膜片钳实验系统，研究粉防己碱对分离的豚鼠心室肌单细胞动作电位及钙电流的影响。在电流钳制方式下，给予脉宽３ｍｓ，０．５Ｈｚ电流刺激，引出单细胞动作电位，粉防己碱３０μｍｏｌ·Ｌ－１可使ＡＰＤ５０缩短７２．２％，ＡＰＤ９０缩短４４．０％，而静息电住，动作电位幅值无明显改变，在电压钳方式下，保持电位－４０ｍＶ，给予脉宽１５０ｍ５、０．５Ｈｚ去极化刺激可记录到Ｌ型钙通道电流，０．３～３００μｍｏｌ·Ｌ－１粉防己碱浓度依赖性地阻滞钙电流，ＩＣ５０＝１３．３μｍｏｌ·Ｌ－１．粉防己碱对钙通道的电流－电压关系无明显影响。     

白花前胡甲素对豚鼠单一心室肌细胞钙电流的频率依赖性阻断作用

本文利用全细胞膜片钳制技术，观察了白花前胡有效成分Ｐｒａ－Ａ对豚鼠单一心室肌细胞钙电流的影响．结果表明：１，１０，１００μｍｏｌ·Ｌ－１Ｐｒａ－Ａ可使钙电流峰值变小，随浓度增加，作用加强；１０μｍｏｌ·Ｌ－１Ｐｒａ－Ａ对钙电流的抑制具使用依赖性和频率依赖性．结果提示Ｐｒａ－Ａ对钙电流的阻断作用可能是白花前胡抗心律失常作用的机理之一；Ｐｒａ－Ａ可能对快速型心律失常有防治作用．     

甲基莲心碱对心肌细胞I_(Na)、I_(Ca-L)及稳态外向K~+电流的影响

目的　为证明甲基莲心碱（ Ｎｅｆｅｒｉｎｅ, Ｎｅｆ） 对单个心肌细胞离子通道电流的影响及抗心律失常作用的离子通道机制。方法　采用全细胞记录膜片钳技术,记录了 Ｎｅｆ 对培养大鼠心室肌细胞钠电流（ Ｉ Ｎａ） 及豚鼠心室肌细胞动作电位、 Ｉ Ｎａ 、 Ｌ 型钙电流（ Ｉ Ｃａ Ｌ） 及稳态外向 Ｋ＋ 电流的影响。结果　 Ｎｅｆ ３０ ,１００ μｍｏｌ· Ｌ－ １ 明显抑制培养大鼠心室肌细胞 Ｉ Ｎａ ,分别从对照水平的（３４ ±０７） ｎ Ａ 降至（２１ ±０５） 和（０４ ±０２） ｎ Ａ。 Ｎｅｆ １０ μｍｏｌ· Ｌ－ １ 可降低豚鼠心室肌细胞动作电位振幅、静息电位,延长动作电位时程。 Ｎｅｆ １０ ,３０ μｍｏｌ· Ｌ－ １ 分别使豚鼠心室肌细胞 Ｉ Ｎａ 及 Ｉ Ｃａ Ｌ从给药前的（７９ ±２１） ｎ Ａ 和（６８９ ±２４３） ｐ Ａ 降至（４０ ±１４） 、（１３ ±０６） ｎ Ａ和（３７４ ±１７２） 、（１０９ ±６７） ｐ Ａ。 Ｎｅｆ １０ μｍｏｌ· Ｌ－ １ 还抑制 Ｉ Ｎａ 、稳态外向 Ｋ＋ 电流和 Ｉ Ｃａ Ｌ的 Ｉ Ｖ 曲线并使后者的峰值电流电位略右移。结论　 Ｎｅｆ 有钠、 Ｌ 型钙通道阻滞作用并抑制稳态外向 Ｋ＋ 电流,这些可解释     

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.