三七皂甙对血管平滑肌上受体操纵Ca^2＋通道的特异性作用

三七皂甙能明显抑制狗肠系膜动脉及大隐静脉α肾上腺素能受体触发的收缩反应及＾４５Ｃａ内流，但对高Ｋ＾＋引起的Ｃａ＾２＋内流无影响。三七皂甙不影响Ｃａ＾２＋内流无影响。三七皂甙不影响Ｃａ＾２＋释放及受体的亲和力。提示三七皂甙具有特异性阻断受体操纵Ｃａ＾２＋通道的特性，对电位依赖性Ｃａ＾２＋通道无作用。     

三七皂甙对血管平滑肌α受体引起~(45)Ca外溢与内流的影响

在血管平滑肌,三七总皂甙明显减少苯肾上腺素引起的~(45)Ca内流量,不影响高钾引起的~(45)Ca内流;而硝苯吡啶几乎完全阻断后一种的~(45)Ca内流。三七总皂甙不抑制~(45)Ca外溢。结果表明,三七总皂甙能特异阻断血管平滑肌α受体操纵的Ca~(2+)通道而不影响胞内Ca~(2+)释放过程。     

ATP和凝血酶诱导的血管内皮细胞Ca~(2+)内流比较

采用fura 2荧光测定细胞 [Ca2 +]i 变化技术 ,在培养的牛主动脉内皮细胞上观察ATP和凝血酶诱导的Ca2 +内流的特性 .ATP和凝血酶均能诱导内皮细胞 [Ca2 +]i 呈双相升高 ,它们诱导的Ca2 +释放是环匹阿尼酸 (CPA)敏感Ca2 +池的一部分 .ATP诱导的Ca2 +释放和Ca2 +内流不完全通过激活磷脂酶C介导 ,而凝血酶诱导的Ca2 +释放和Ca2 +内流则完全通过激活磷脂酶C介导 .硝苯地平对ATP和凝血酶诱导的Ca2 +内流均无影响 ;SK&F 96 36 5与三七皂甙 2A对凝血酶诱导的Ca2 +内流没有影响 ,但可抑制ATP诱导的Ca2 +内流 ,且此作用比它们对CPA诱导Ca2 +内流的抑制作用小 .SK&F 96 36 5和三七皂甙 2A敏感的Ca2 +内流的特性不同 .结果表明ATP和凝血酶激活不同受体 ,引起Ca2 +内流的机理不同     

胍丁胺对兔窦房结起搏细胞的电生理效应(英文)

目的:研究胍丁胺(Agm)对兔窦房结起搏细胞的电生理效应及其作用机制。方法:应用玻璃微电极方法。结果:Agm不仅能剂量依赖地抑制兔窦房结起搏细胞的V_(max),APA和VDD,RPF;而且能延长APD_(90);idazoxan能明显抑制Agm的电生理效应;而L-NAME不能影响Agm的电生理效应;提高灌流液中的Ca~(2 )浓度可对抗Agm的作用;ATP-敏感性钾通道开放剂(lemakalim)可部分拮抗Agm延长APD_(90)的作用。结论:Agm对窦房结的电生理效应由肾上腺素能α-受体和咪唑啉受体介导,并与Ca~(2 )内流和K~ 外流减少有关。     

三七总皂甙对小白鼠运动神经末梢递质释放的影响

胞内记录神经—终板电位及微终板电位,证明三七总皂甙不影响神经末梢去极化时Ca~(2+)及Ba~(2+)的内流,对同步、非同步及自发性的量子释放均无减弱。由于Cd~(2+)能明显减弱量子释放,而PNS与nifedipine却无作用,提示胆碱能运动神经末梢上参与递质释放的Ca~(2+)通道属于N型Ca~(2+)通道。     

胍丁胺抑制兔房室结细胞的自发活动(英文)

目的:研究胍丁胺(Agm)对兔房室结细胞自发活动的影响及其作用机制.方法:应用玻璃微电极方法.结果:Agm不仅剂量依赖地抑制兔房室结细胞自发活动的V_(max),APA和VDD,RSF;而且延长APD_(90);idazoxan能明显抑制Agm的作用;而L-NAME不能影响Agm的作用;提高灌流液中的Ca~(2 )浓度可对抗Agm的作用;ATP-敏感性钾通道开放剂(lemakalim)可拮抗Agm延长APD_(90)的作用.结论:Agm对房室结细胞自发活动的抑制作用由咪唑啉受体和/或肾上腺素α_2-受体介导,并与Ca~(2 )内流和K~ 外流减少有关.     

高盐抑制胸主动脉内皮细胞一氧化氮生成及其机制

目的探究小鼠胸主动脉内皮细胞高盐模型对一氧化氮(nitric oxide,NO)生成的影响。方法使用瞬时受体电位香草素4(transient receptor potential vanilloid 4,TRPV4)抑制剂HC067047对胸主动脉内皮细胞预孵育后,通过钙离子荧光探针Fluo-4和NO荧光探针DAF-FM DA进行Ca~(2+)以及NO标记,研究TRPV4对NO产生的影响。以60 mmol·L~(-1)高盐刺激胸主动脉内皮细胞,检测Ca~(2+)内流以及NO的生成情况。结果与对照组相比,抑制TRPV4减少胸主动脉内皮细胞Ca~(2+)内流及NO的生成;与同渗透压的甘露醇相比,高盐抑制胸主动脉内皮细胞中TRPV4介导的Ca~(2+)内流及NO的生成。结论高盐状态下,通过抑制TRPV4通道导致Ca~(2+)内流减少,NO的生成下降。     

粉防己碱、蝙蝠葛碱对高K~+引起突触体~(45)Ca内流的影响

<正> 钙离子在中枢神经系统的功能调控及许多病理过程中都有重要作用。而大多数经典钙拮抗剂对神经元Ca~(2+)通道不敏感。最近我们研究表明某些四氢异喹啉类化合物,如蝙蝠葛苏林碱对神经元Ca~(2+)通道有相对选择性拮抗作用。为了进一步确定四氢异喹啉类化合物对神经元Ca~(2+)通道的拮抗活性,我们观察粉防已碱、蝙蝠葛碱对突触体~(45)Ca内流的影响.实验方法Sprague-Dawley大鼠,体重200±23g,雌雄兼用。大鼠断头,迅速分离大脑皮层,制备突触体。用酚试剂法测定蛋白含量,突触体反应浓度为0.9g/L。按文献测定~(45)Ca内流。高K~+(65mmol/L)去极引起”快相”~(45)Ca内流反应时间为20s。净~(45)Ca内流量△(Ca~(2+))i=高K~+引起“快相”~(45)Ca内流—基础~(45)Ca内流。     

何谓钙拮抗剂?目前临床上常用的有哪几种?

<正> 钙拮抗剂的基本作用是阻滞心肌及平滑肌(如冠脉或外周血管平滑肌)细胞的慢Ca~(2+)通道,抑制Ca~(2+)向细胞的内流,故又称钙通道阻滞剂(或抑制剂)。电生理研究证实,心肌细胞动作电位曲线中0相的快速上升是由于Na~+内流所致,钙拮抗剂不影响或很少影响其过程;2相的平台由Ca~(2+)内流所维持,故能被钙拮抗剂所抑制。而属于慢自律细胞的窦房结和房室     

钙拮抗药治疗高血压病的分析

<正> 钙拮抗药(Calcium antagonist)原为抗心绞痛、抗心律失常药,现在药物学上把其单列为一类,从1978年开始就用于高血压的治疗。钙拮抗药是由一系列结构不同,药理特性不全相同的药物组成,因此其作用机理既不能用简单的构效关系,也不能用同一机理或同一受体加以阐明,现认为是一类能选择性地减少慢通道的Ca~(2+)内流,干扰细胞内Ca~(2+)的浓度而影响细胞功能的药物。已知Ca~(2+)通道有两类:一为受体     

Synthesis,Cytotoxicity and Antileishmanial Activity of Some N-(2-(indol-3-yl)ethyl)-7-chloroquinolin-4-amines

We report herein the condensation of 4,7-dichloroquinoline (1) with tryptamine (2) and D-tryptophan methyl ester (3) . Hydrolysis of the methyl ester adduct (5) yielded the free acid (6) . The compounds were evaluated in vitro for activity against four different species of Leishmania promastigote forms and for cytotoxic activity against Kb and Vero cells. Compound (5) showed good activity against the Leishmania species tested, while all three compounds displayed moderate activity in both Kb and Vero cells.     

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.     

Lung disease and PKCs

The lung offers a rich opportunity for development of therapeutic strategies focused on isozymes of protein kinase C (PKCs). PKCs are important in many cellular responses in the lung, and existing therapies for pulmonary disorders are inadequate. The lung poses unique challenges as it interfaces with air and blood, contains a pulmonary and systemic circulation, and consists of many cell types. Key structures are bronchial and pulmonary vessels, branching airways, and distal air sacs defined by alveolar walls containing capillaries and interstitial space. The cellular composition of each vessel, airway, and alveolar wall is heterogeneous. Injurious environmental stimuli signal through PKCs and cause a variety of disorders. Edema formation and pulmonary hypertension (PHTN) result from derangements in endothelial, smooth muscle (SM), and/or adventitial fibroblast cell phenotype. Asthma, chronic obstructive pulmonary disease (COPD), and lung cancer are characterized by distinctive pathological changes in airway epithelial, SM, and mucous-generating cells. Acute and chronic pneumonitis and fibrosis occur in the alveolar space and interstitium with type 2 pneumocytes and interstitial fibroblasts/myofibroblasts playing a prominent role. At each site, inflammatory, immune, and vascular progenitor cells contribute to the injury and repair process. Many strategies have been used to investigate PKCs in lung injury. Isolated organ preparations and whole animal studies are powerful approaches especially when genetically engineered mice are used. More analysis of PKC isozymes in normal and diseased human lung tissue and cells is needed to complement this work. Since opposing or counter-regulatory effects of selected PKCs in the same cell or tissue have been found, it may be desirable to target more than one PKC isozyme and potentially in different directions. Because multiple signaling pathways contribute to the key cellular responses important in lung biology, therapeutic strategies targeting PKCs may be more effective if combined with inhibitors of other pathways for additive or synergistic effect. Mechanisms that regulate PKC activity, including phosphorylation and interaction with isozyme-specific binding proteins, are also potential therapeutic targets. Key isotypes of PKC involved in lung pathophysiology are summarized and current and evolving therapeutic approaches to target them are identified.     

Gender-related symptoms and correlates of alcohol dependence among men and women with a lifetime diagnosis of alcohol use disorders

This study explored gender-related symptoms and correlates of alcohol dependence in a crosssectional study of 150 men and 150 women with a lifetime diagnosis of alcohol use disorders (AUD). Participants were recruited in equal numbers from treatment settings, correctional centres and the general community. Standardized measures were used to determine participants' use of substances, history of psychiatric disorders and psychosocial stress, their sensation seeking and family history of substance use and mental health disorders. Multivariate analyses were used to detect patterns of variables associated with gender and the lifetime severity of AUD. Men had a longer history of severe AUD than women. Women had similar levels of alcohol dependence and medical and psychological sequelae as men, despite 6 fewer years of AUD. More women than men had a history of severe psychosocial stress, severe dependence on other substances and antecedent mental health problems, especially mood and anxiety disorders. There were differences in family history of alcohol-related problems approximating same-gender aggregation. The severity of a lifetime AUD was predicted by its earlier age at onset and the occurrence of other disorders, especially anxiety, among both men and women. The limitations in the generalizability of these findings due to sample idiosyncrasies are discussed.     

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.