氯丙烯对神经细胞内 Ca~(2 ),游离钙调素,环腺苷酸含量和钙/钙调素依赖性蛋白激酶Ⅱ活性的影响

氯丙烯对神经细胞内Ｃａ２＋，游离钙调素，环腺苷酸含量和钙／钙调素依赖性蛋白激酶Ⅱ活性的影响孙克任谢克勤高树君张磊（山东医科大学毒理学研究室，济南２５００１２）用鸡胚脑神经细胞研究了氯丙烯作用下细胞内Ｃａ２＋，游离钙调素（ＣａＭ）和环腺苷酸（ｃＡＭＰ）...     

螺旋藻多糖对小鼠脾细胞中环腺苷酸浓度的影响

目的：对螺旋藻免疫调节作用的机理进行研究。方法：采用竞争性蛋白结合分析法，研究螺旋藻多糖（ Ｓｐｉｒｕｌｉｎａ ｐｌａｔｅｎｓｉｓ ｐｏｌｙｓａｃｃｈａｒｉｄｅｓ，ＳＰＰ） 对小鼠脾细胞中第二信使环腺苷酸（ｃＡＭＰ） 浓度的影响。结果：ＳＰＰ可剂量依赖性引起小鼠脾细胞中ｃＡＭＰ浓度的升高。结论：ＳＰＰ免疫调节作用的重要机制之一是对脾细胞中第二信使ｃＡＭＰ浓度的影响。关键词　螺旋藻多糖，环磷酸腺苷，脾细胞     

考福新或咪唑二酮增强内皮素—1升高大鼠主动脉腺苷环—磷酸

硝苯啶（１００ｎｍｏｌ．Ｌ＾－１）或无细胞外钙抑制内皮素－１（ＥＴ－１）收缩大鼠胸主动脉８０％以上。ＥＴ－１（２０ｎｍｏｌ．Ｌ＾－１；１５．２５ｍｉｎ）增加血管环腺苷酸（ｃＡＭＰ）含量，该作用被咪唑二酮（１００μｍｏｌ．Ｌ＾－１）增强。ＥＴ－１还能增加福斯科林的增加ｃＡＭＰ作用。本文证明ＥＴ－１收缩大鼠胸主动脉于少涉及两种信息转导机制，即开放硝苯啶敏感性钙通道和增加ｃＡＭＰ。     

磷酸二酯酶同工酶Ⅲ和Ⅳ调节气管平滑肌环腺苷酸的区域化分布

磷酸二酯酶同工酶Ⅳ（ＰＤＥⅣ）抑制剂咯利普兰（Ｒｏｌ，３０μｍｏｌ·Ｌ－１）对３０μｍｏｌ·Ｌ－１异丙肾上腺素所致的犬气管平滑肌环腺苷酸（ｃＡＭＰ）积聚的增强作用比ＰＤＥⅢ抑制剂氰胍哒嗪（ＳＫＦ９４８３６，３０μｍｏｌ·Ｌ－１）要强，但对异丙肾上腺素所致的犬气管平滑肌松弛的增强作用比ＳＫＦ９４８３６要弱．３０μｍｏｌ·Ｌ－１Ｒｏｌ或ＳＫＦ９４８３６对３０μｍｏｌ·Ｌ－１福斯科林所致的犬气管平滑肌松弛与ｃＡＭＰ积聚的增强作用程度几乎相等．异丙肾上腺素，福斯科林单独或与ＳＫＦ９４８３６，Ｒｏｌ合用都仅引起犬气管平滑肌的可溶部ｃＡＭＰ积聚，对颗粒部ｃＡＭＰ含量无明显影响．上述结果提示犬气管平滑肌存在着ｃＡＭＰ的区域化分布，它受ＰＤＥⅢ，ＰＤＥⅣ的调节，而与平滑肌细胞的亚细胞结构无关     

肺泡巨噬细胞内cAMP和cGMP与肺气虚证的关系

检测７６例慢性支气管炎患者及３６例正常人血、支气管肺灌洗液（ＢＡＬＦ）和肺泡巨噬细胞（ＡＭ）内ｃＡＭＰ和ｃＧＭＰ。结果表明：（１）正常人与肺气虚证患者外周血、ＢＡＬＦ和ＡＭ内ｃＡＭＰ及ｃＧＭＰ无明显差异。（２）肺气虚证舒喘灵对ＡＭ内ｃＡＭＰ之刺激率明显低于正常人，而皮质激素ＡＭ内ｃＡＭＰ和ｃＡＭＰ及ｃＧＭＰ有助于深入研究肺气虚证的本质。     

褪黑素对类风湿关节炎病人外周血淋巴细胞增殖反应的影响及其G蛋白-cAMP信号转导机制的研究

目的研究褪黑素（ＭＴ）对类风湿关节炎（ＲＡ）病人外周血淋巴细胞（ＰＢＬ）增殖反应的影响及其Ｇ蛋白 ｃＡＭＰ信号转导机制。方法淋巴细胞增殖法、ｃＡＭＰ放免测定及Ｇ蛋白功能分析。结果ＲＡ病人ＰＢＬ增殖能力低于正常人１０倍左右，ＭＴ在１×１０－８～１×１０－６ｍｏｌ·Ｌ－１能明显促进ＲＡ病人ＰＢＬ的增殖反应；ＲＡ病人ＰＢＬ的ｃＡＭＰ水平明显高于正常人，ＭＴ（１×１０－６ｍｏｌ·Ｌ－１）可部分使其降低，且ＭＴ的这一作用能被百日咳毒素（ＰＴ）取消。结论ＭＴ可促进ＲＡ病人ＰＢＬ的增殖反应，ＰＴ敏感的Ｇｉ蛋白 ｃＡＭＰ信号转导机制参与了ＭＴ上调ＰＢＬ的作用     

CHF患者cAMP cGMP和NE ANF的变化及临床意义

通过放免法和高压液相色谱－电化学法，测定了９２例充血性心力衰竭（ＣＨＦ）患者血浆环核苷酸（ｃＡＭＰ、ｃＧＭＰ）、心钠素（ＡＮＦ）和去甲肾上腺素（ＮＥ）水平。结果表明：血浆ｃＡＭＰ、ｃＧＭＰ和ＡＮＦ、ＮＥ浓度随着心衰程度加重而显著增加，ｃＡＭＰ／ｃＧＭＰ比值下降，与病因无关；心衰纠正后，上述指标明显恢复。血浆ｃＡＭＰ、ｃＧＭＰ与ＮＥ、ＡＮＦ水平显著相关。提示：血浆环核苷酸浓度同ＮＥ、ＡＮＦ一样，可作为评价ＣＨＦ患者心功能和观察疗效的一种生化指标。     

联合用药治疗中老年冠心病心力衰竭的临床观察

目的观察葡甲胺环腺苷酸联合β2阻滞剂治疗中老年冠心病心力衰竭的临床疗效。方法设立对照分析,治疗组用葡甲胺环腺苷酸联合β2阻滞剂治疗,对照组用洋地黄利尿剂及血管活性药治疗,观察两组治疗前后心功能变化情况以评估疗效。结果治疗组总有效率为85.3%,对照组为62.5%,比较有极显著性差异(P<0.01)。结论葡甲胺环腺苷酸联合β2阻滞剂在控制中老年心衰及稳定病情等方面有较好的疗效。     

环磷腺苷葡甲胺与氨力农治疗充血性心力衰竭的疗效 …

目的：比较环磷腺苷葡甲胺（ＭＣＡ）与氨力农治疗充血性心力衰竭的疗效。方法：充血性心力衰竭病人８０例分为ＭＣＡ组与氨力农组。ＭＣＡ组５０例，以ＭＣＡ１８０ｍｇ加于５％葡萄糖注射液２５０ｍＬ中静脉滴注（静滴）２ｈ，ｑｄ，共１４ｄ。氨力农组３０例，以氨力农注射液５０ｍｇ加于１４ｄ。     

钒酸盐对糖尿病大鼠糖原的影响与cAMP的关系

目的在链脲佐菌素（ＳＴＺ）糖尿病大鼠模型观察钒酸盐（Ｖａ）对骨骼肌和肝脏糖原的影响与ｃＡＭＰ的关系。方法用正钒酸钠分别管饲正常对照大鼠和ＳＴＺ致糖尿病大鼠，观测肝脏和骨骼肌的糖原与ｃＡＭＰ的变化趋势。结果与正常对照组比较，糖尿病骨骼肌糖原含量下降（Ｐ＜０．０１），肝糖原含量升高（Ｐ＜０．０１）；Ｖａ使肌糖原上升４７％（Ｐ＜０．０１），肝糖原下降５０％（Ｐ＜０．０１），均恢复至正常水平，提示至少有部分肝糖原向骨骼肌转移。Ｖａ同时升高肝ｃＡＭＰ，降低骨骼肌ｃＡＭＰ，与糖尿病动物使用Ｖａ后肌肝糖原变化相反。结论本试验提示ｃＡＭＰ在Ｖａ导致的肝糖原向骨骼肌转移中发挥一定作用。     

乙酰胆碱介导的内皮超极化因子对海马神经元缺氧/再给氧损伤的保护作用

目的研究乙酰胆碱(acetylcholine,ACh)介导的大鼠大脑中动脉内皮释放的内皮超极化因子(endothelium-de-pendent hyperpolarizing factor,EDHF)对海马神经元缺氧/再给氧损伤的保护作用。方法用原代培养的大鼠海马神经元细胞建立缺氧/再给氧损伤模型,取大鼠大脑中动脉(mid-dle cerebral artery,MCA)血管段,PGI2和NO的阻断剂NG-ni-tro-L-argininemethyl ester(L-NAME)和indomethacin(Indo)预处理后,用ACh刺激血管内皮释放EDHF,用四甲基偶氮唑盐(MTT)染色吸光度和乳酸脱氢酶(LDH)活性作为细胞损伤指标,用激光共聚焦显微镜检测细胞内游离Ca2+浓度。结果与正常对照组相比,缺氧/再给氧损伤组细胞MTT染色吸光度明显降低,上清液中LDH活性和细胞内Ca2+浓度则明显升高。1μmol.L-1ACh合用含血管内皮的MCA血管段(MCA/Endo)或ACh+MCA/Endo+L-NAME+Indo均可抑制缺氧/再给氧致海马细胞MTT染色吸光度降低、培养上清液中LDH活性及细胞内Ca2+浓度的升高,但单用1μmol.L-1ACh或MCA/Endo却无上述抑制作用,合用1μmol.L-1ACh和去内皮MCA血管段(MCA/-Endo)也无明显抑制作用。K+在25~35μmol.L-1范围内,可明显减弱ACh+MCA/Endo+L-NAME+Indo对缺氧再给氧致海马神经细胞MTT染色吸光度降低、上清液LDH活性及细胞内Ca2+浓度升高的抑制作用,但Ba2+没有明显影响。结论假定的EDHF对原代培养的海马神经元缺氧/再给氧损伤具有保护作用,其机制可能与抑制缺氧/再给氧引起的钙超载有关。     

Role of cAMP in the effects of K+ on the steroidogenesis of zona glomerulosa cells

1. Investigations of the role of cAMP in the stimulation of the steroidogenesis of zona glomerulosa (ZG) cells by increased extracellular K+ concentration are reviewed. 2. Possible reasons for discrepancies in the results of different investigators on whether K+ increases the cAMP content or output of ZG tissue or dispersed cells are discussed. 3. The concentration of cAMP in the incubating media of ZG tissue or cells, rather than their cAMP content, seems to respond more sensitively to stimulation by extracellular K+, as was also found for adrenocorticotropic hormone stimulation of zona fasciculata-reticularis cells. 4. The addition of the phosphodiesterase inhibitor 1-methyl-3-isobutylxanthine (IBMX) to incubations with the aim of increasing the sensitivity of the response in cAMP to extracellular K+ in ZG cells may give rise to effects, probably nonspecific, which actually inhibit the measured response. 5. The immediate stimulation in the steroidogenesis of ZG cells with raised extracellular K+ is probably mostly due to the direct effect of increases in cytoplasmic Ca2+ (arising from increases in Ca2+ influx) on mitochondrial processes. However, increases in cAMP may prolong the stimulation of steroidogenesis by increased extracellular K+. This increased cAMP is probably due to stimulation of adenylyl cyclase activity. 6. It has been concluded that the increase in Ca2+ influx output after rises in the extracellular K+ concentration of ZG cells is responsible for most of the increase in cAMP. 7. According to one group of investigators, there is weak stimulation of phospholipase C (PLC) activity after increasing the extracellular K+ concentration of rat ZG cells. 8. If there is such a stimulation of PLC activity, it seems that the action of increased extracellular K+ can potentially involve all known mechanisms for the stimulation of steroidogenesis in endocrine cells. The common primary event is probably the increase in Ca2+ influx. The relative importance of these various potential mechanisms may depend on the particular in vitro conditions used.     

Ca^2＋ participates in α1B-adrenoceptor-mediated cAMP response in HEK293 cells

AIM: To investigate the alpha1B-adrenoceptor (alpha1B-AR)-mediated cAMP response and underlying mechanisms in HEK293 cells. METHODS: Full-length cDNA encoding alpha1B-AR was transfected into HEK293 cells using the calcium phosphate precipitation method, and alpha1B-AR expression and cAMP accumulation were determined by using the saturation radioligand binding assay and ion-exchange chromatography, respectively. RESULTS: Under agonist stimulation, alpha1B-AR mediated cAMP synthesis in HEK293 cells, and blockade by PLC-PKC or tyrosine kinase did not reduce cAMP accumulation induced by NE. Pretreatment with pertussis toxin (PTX) had little effect on basal cAMP accumulation as well as norepinephrine (NE)-stimulated cAMP accumulation. In addition, pretreatment with cholera toxin (CTX) neither mimicked nor blocked the effect induced by NE. The extracellular Ca2+ chelator egtazic acid (EGTA), nonselective Ca2+ channel blocker CdCl2 and calmodulin (CaM) inhibitor W-7 significantly reduced NE-induced cAMP accumulation from 1.59%+/-0.47% to 1.00%+/-0.31%, 0.78%+/-0.23%, and 0.90%+/-0.40%, respectively. CONCLUSION: By coupling with a PTX-insensitive G protein, alpha1BAR promotes Ca2+ influx via receptor-dependent Ca2+ channels, then Ca2+ is linked to CaM to form a Ca2+-CaM complex, which stimulates adenylyl cyclase (AC), thereby increasing the cAMP production in HEK293 cell lines.     

Inhibition of Ca2+ influx by pentoxifylline in NR8383 alveolar macrophages.

Pentoxifylline (PTF), a phosphodiesterase (PDE) inhibitor, can prevent inflammation and tissue damage in animal and in vitro human studies. However, the underlying mechanism remains unclear. Since Ca2+ is a critical signal regulating the release of inflammatory mediators in macrophages, the effects of PTF on Ca2+ influx were examined in NR8383 alveolar macrophages (AMs). PTF induced a dose-dependent inhibition on Ca2+ influx activated by zymosan and by protein kinase C (PKC) activators 1,2-dioctanoyl-sn-glycerol (DOG) or phorbol-12-myristate 13-acetate (PMA). The inhibition appeared to be specifically on the receptor-operated Ca2+ entry. The capacitative Ca2+ entry was not affected by PTF. The inhibition was not due to altered cAMP levels since the zymosan-activated Ca2+ influx was not affected by the adenylate cyclase activator forskolin, nor by dibutyryl cAMP. Pretreatment with protein tyrosine kinase (PTK) inhibitor genistein abolished zymosan-induced, but not DOG-induced Ca2+ influx, suggesting that PTK is an upstream element of the signaling cascade and not the target of PTF. The Ca2+ entry activated by zymosan and by PKC activators was inhibited by the mitogen-activated protein kinase (MAPK) inhibitor PD98059. Moreover, activation of MAPK by C6-ceramide (C6C) triggered a similar Ca2+ influx as elicited by zymosan and PKC activators, suggesting that MAPK is an element of the pathway. The C6C-induced Ca2+ influx was also inhibited by PTF. These results indicate that PTF blocks the receptor-operated Ca2+ influx in NR8383 AMs by inhibiting PDE which may acts as a downstream element of the signaling pathway or by direct interaction with Ca2+ channels.     

NQ-Y15 inhibits the calcium mobilization by elevation of cyclic AMP in rat platelets

2-1(4-Cyanophenyl)aminol-3-chloro-1,4-naphthalenedione (NQ-Y15) is a dual action drug which acts as a thromboxane A2 (TXA2) synthase inhibitor and TXA2/PGH2 receptor antagonist. In the present study, we examined the effects of NQ-Y15 on Ca2+ mobilization, which is the common event in various types of platelet activation, in arachidonic acid (AA)-stimulated rat platelets. The elevation of cytosolic Ca2+ concentration ([Ca2+]i) induced by AA was inhibited by NQ-Y15 in a concentration-dependent manner. This inhibition-effect of NQ-Y15 was found to be based on the suppression of the rise in [Ca2+]i by the inhibition of both Ca2+ release from internal stores and Ca2+ influx from the extracellular space. Our successive trial was focused on the role of cyclic AMP (cAMP) in the action of NQ-Y15, because cAMP was reported to be increased by dual action drugs such as picotamide and to inhibit the increase in [Ca2+]i. NQ-Y15 was confirmed to increase cAMP in AA-stimulated rat platelets. These results suggested that NQ-Y15 might inhibit the rise in [Ca2+]i in AA-treated rat platelets by increasing cAMP, which is involved in the inhibition of platelet activation.     

Differences in Ca2+ entry blockers revealed by effects on adenosine- and adrenergic- receptors and cyclic AMP levels of [2-3H]adenine-prelabeled vesicles prepared from guinea pig brain

Three major classes of Ca2+ entry blockers, classified according to effects on cardiac and vascular smooth muscle, were tested. Vesicles prepared from cerebral cortex and stimulated by adenosine and epinephrine constituted adenosine and alpha-adrenergic receptor systems respectively. Vesicles prepared from cerebellum and stimulated by epinephrine constituted the beta-adrenergic receptor system. Experiments with adenosine were also performed with vesicles formed or incubated in the absence of exogenous Ca2+. The results indicate that Ca2+ entry blockers had a variety of effects, even within classes of drugs. Vascular-selective group A Ca2+ entry blockers such as nifedipine and nisoldipine antagonized adenosine, but the structurally-related drug nitrendipine was inactive. Inhibition was competitive with adenosine and independent of exogenous Ca2+. In contrast to receptor-binding studies requiring high ratios of the drugs to adenosine receptor radioligands, nifedipine and nisoldipine were inhibitory at equimolar concentrations with adenosine. Non-selective group A Ca2+ entry blockers such as diltiazem and verapamil were inactive against adenosine. Group B Ca2+ entry blockers, prenylamine and perhexilene, increased cyclic AMP (cAMP) levels of vesicles stimulated by adenosine but not by epinephrine or under basal conditions. This effect was observed only in vesicles that had been formed in the presence of Ca2+. Ca2+ entry blockers also exhibited effects on adrenergic receptors unrelated to effects on adenosine. Verapamil and prenylamine acted as alpha-adrenergic antagonists and only prenylamine acted as a beta-adrenergic antagonist. However, the vesicle system also revealed indirect blocking actions of nifedipine on adrenergic receptor systems. The actions of the Ca2+ entry blockers are discussed in relation to the special usefulness of nifedipine in the treatment of patients with defective atrioventricular conduction and also in relation to the unique ability of group B Ca2+ entry blockers to selectively inhibit Ca2+ and calmodulin activated phosphodiesterase. However, some caution must be applied in drawing conclusions relating to the cardiovascular actions of these drugs from data generated in a neuronally-derived model.     

粉防己碱的抗炎作用与炎症白细胞cAMP的关系

目的　研究粉防己碱 (tetrandrine,Tet)的抗炎作用与炎症白细胞cAMP的关系。方法　在大鼠胸膜腔内注射角叉菜胶 (1 0mg·kg- 1 )复制胸膜炎 ,并于致炎前 30min腹腔注射Tet。用常规方法测量胸膜腔渗出液量 ,用试管稀释法计数渗出液中白细胞数 ,用放射免疫分析法、间接法、酶放射化学分析法和荧光比色法 ,分别测定炎症白细胞cAMP浓度、腺苷酸环化酶 (AC)、磷酸二酯酶 (PDE)活性及胞质内游离钙浓度 ([Ca2 + ] i) ;体外观察细胞外钙对Tet调节炎症白细胞PDE活性的作用。结果　Tet(1 0～ 80mg·kg- 1 )腹腔注射 ,剂量依赖地降低胸膜腔渗出液量和白细胞游出数 ,同时增加白细胞cAMP浓度 ;Tet亦剂量依赖地降低炎症白细胞PDE活性及 [Ca2 + ] i,但对白细胞AC活性无明显影响。Tet抑制炎症渗出的作用与其增加白细胞cAMP浓度的作用呈线性相关 ;其增加白细胞cAMP浓度的作用则与其抑制PDE活性呈线性相关 ;后者与其降低 [Ca2 + ] i 呈线性相关。在体外 ,Tet抑制细胞外Ca2 + 和A2 31 87引起的PDE活性升高 ,其抑制作用可因细胞外钙浓度增加而逆转。结论　增加炎症白细胞cAMP浓度可能是Tet重要的抗炎作用机制之一 ;Tet主要通过降低炎症白细胞 [Ca2 + ] i从而抑制PDE活性并最终减少cAMP降解 ,Tet对AC活性无明显影响     

葡甲胺环腺苷酸对心肌收缩性、耗氧量和兴奋性的影响

在0.01～10mM范围内,累积加入MCA可加强豚鼠右心室乳头状肌和兔右心房肌的收缩力,外源性cAMP则减弱乳头状肌的收缩力。MCA产生正变力效应的峰时间需10～15min。Warburg测压法表明MCA可显著增加大鼠心室肌匀浆的耗氧量,而外源性cAMP对此值无影响。10mM MCA可抑制豚鼠右心室乳头状肌的兴奋性,使强度时间曲线右移。     

Mechanisms of action of novel cardiotonic agents

Regulation of myocardial contractility by cardiotonic agents is achieved by an increase in intracellular Ca2+ mobilization (upstream mechanism), an increase in Ca2+ binding affinity to troponin C (central mechanism), or facilitation of the process subsequent to Ca2+ binding to troponin C (downstream mechanism). cAMP mediates the regulation induced by Ca2+ mobilizers such as beta-adrenoceptor agonists and selective phosphodiesterase III inhibitors acting through the upstream mechanism. These agents act likewise on the central mechanism to decrease Ca2+ sensitivity of troponin C in association with the cAMP-mediated phosphorylation of troponin I. In addition to such a well-known action of cAMP, recent experimental findings have revealed that Ca2+ sensitizers, such as levosimendan, OR-1896, and UD-CG 212 Cl, require the cAMP-mediated signaling for induction of Ca2+ sensitizing effect. These agents shift the [Ca2+] -force relationship to the left, but their positive inotropic effect (PIE) is inhibited by carbachol, which suppresses selectively the cAMP-mediated PIE. These findings imply that cAMP may play a crucial role in increasing the myofilament Ca2+ sensitivity by cross-talk with the action of individual cardiotonic agents. No clinically available cardiotonic agents act primarily via Ca2+ sensitization, but the PIE of pimobendan and levosimendan is partly mediated by an increase in myofilament Ca2+ sensitivity. Evidence is accumulating that cardiotonic agents with Ca2+ sensitizing action are more effective than agents that act purely via the upstream mechanism in clinical settings. Further clinical trials are required to establish the effectiveness of Ca2+ sensitizers in long-term therapy for congestive heart failure patients.