Modulation of release of ATP in the major pelvic ganglion of rats

用荧光素－荧光素酶方法测定大鼠盆总神经节腺苷三磷酸（ＡＴＰ）释放．钠通道阻断剂河豚毒素（１μｍｏｌ·Ｌ－１）抑制电刺激诱发的盆总神经节ＡＴＰ的释放．灌流液中去除Ｃａ２＋并加入ＥＧＴＡ（１ｍｍｏｌ·Ｌ－１）后消除ＡＴＰ的释放．腺苷（１００μｍｏｌ·Ｌ－１），Ａ１腺苷受体激动剂环戊腺苷（０．１μｍｏｌ·Ｌ－１），毒蕈碱性受体激动剂氧化震颤素（１μｍｏｌ·Ｌ－１）和５－羟色胺（１００μｍｏｌ·Ｌ－１）减少ＡＴＰ的释放．Ａ１腺苷受体拮抗剂８－环戊基－１，３－二丙基黄嘌呤（１０ｎｍｏｌ·Ｌ－１），α２肾上腺素受体拮抗剂育亨宾（３μｍｏｌ·Ｌ－１），Ｄ２多巴胺受体拮抗剂舒必利（２０μｍｏｌ·Ｌ－１）和组胺（１００μｍｏｌ·Ｌ－１）增加ＡＴＰ的释放．结果提示，在大鼠盆总神经节存在着作为神经递质参与突触传递的ＡＴＰ释放．Ａ１腺苷受体，毒蕈碱性受体，α２肾上腺素受体，Ｄ２多巴胺受体，５－羟色胺受体及Ｈ１组胺受体激动剂或拮抗剂可以通过节前机制影响ＡＴＰ的释放     

Analysis of electronic structures of physostigmine analogs

ＡｎａｌｙｓｉｓｏｆｅｌｅｃｔｒｏｎｉｃｓｔｒｕｃｔｕｒｅｓｏｆｐｈｙｓｏｓｔｉｇｍｉｎｅａｎａｌｏｇｓＨＵＺｅｎｇＪｉａｎ，ＪＩＡＮＧＨｕａＬｉａｎｇ，ＣＨＥＮＪｉａｎＺｈｏｎｇ，ＣＨＥＮＫａｉＸｉａｎ１，ＪＩＲｕＹｕｎ（Ｓｈａｎｇｈａｉ...     

Cases analysis of rational use of medicine（45） Hypertension of Pregnancy

1.患者简介患者,女性,19岁,妊娠25周时,出现头痛,恶心,上腹部不适,血压162/108 mmHg,间隔6小时后再测血压,仍是162/108 mmHg。患者无高血压患病史。尿蛋白检查:+诊断:子痫前期(原名先兆子痫)2.用药     

Anionic subsite of active center of Torpedo acetylcholinesterase constructs a part of its conformati

目的：研究电鳐乙酰胆碱酯酶（ＡＣｈＥ）结构功能关系，探讨ＡＣｈＥ负矩部位是否是其构象决定簇的一个组成部分．方法：用ＥＬＩＳＡ及酶抑制实验观察ＡＣｈＥ负矩部位探针２ＰＡＭ对ＡＣｈＥ与其ＭｃＡｂ３Ｆ３之间的免疫反应性的影响．结果：ＭｃＡｂ３Ｆ３不能与２ＰＡＭ及ＡＣｈＥ的复合物反应；２ＰＡＭ浓度依赖性地降低ＭｃＡｂ３Ｆ３对ＡＣｈＥ的抑制率；但不能解离ＡＣｈＥ与３Ｆ３构成的抗原抗体复合物．结论：电鳐ＡＣｈＥ活性中心负矩部位构成其活性中心构象抗原决定簇的一部分．     

Comparison of the determination of β-lactam antibiotic drugs in plasma of rabbits by means of HPLC and of a microbiological assay

The present study compares the determination of the plasma concentrations of ampicillin, amoxycillin and cefuroxime in rabbits, by means of high performance liquid chromatography and the microbiological assay. The correlation coefficient between the data obtained by these methods are for ampicillin 0.991, amoxycillin 0.994 and cefuroxime 0.991. Plasma constituents interfering with amoxycillin in theHplc determinations, were not encountered in the plasma of man.     

Effects of schisanhenol on antitumoractivity of adriamycin

<正> It was suggested that adriamycin (ADM) may have at least two mechanisms of tissue damage. One, which involves lipid peroxidation, is blocked by the free radical scavenger, appears to play a major role in the development of cardiomyopathy. The other, which may involve binding of ADM to DNA, appears to be the major determinant of ADM toxicity for tumor cells. So the antitumor efficiency of ADM may be dissociated from its side effect of     

(Journal of China University of Geoscien

转化及土壤重金属污染的治理等方面起重要作用,关于有机酸是否影响矿物风化的问题,自1826年Sprengel和Julien为土壤中的有机酸是否在矿物溶解中扮演重要角色展开争论以来,已经持续     

Measurement of biological activity of somatotropin in hypophysectomized rats

目的：建立测定生长激素（ＧＨ）在体生物活性的方法．方法：以去垂体大鼠体重增长（ＢＷＧ）和胫骨骺软骨板宽度（ＴＥＷ）为指标，观察动物性别、给药途径、次数和周期不同对效应的影响；同时进行４ｄＢＷＧ，６ｄＢＷＧ和６ｄＴＥＷ法，测定ＧＨ的效价（平行线３×３设计）．结果：♀和♂ｓｃ和ｉｍ给药以及每日给药１次和２次的ＢＷＧ和ＴＥＷ差异无显著意义．给药６ｄ比给药４ｄ引起较大的ＢＷＧ和ＴＥＷ（Ｐ＜００５）．４ｄＢＷＧ法和６ｄＢＷＧ法在００２０－０５００ＩＵ·ｄ－１有较好的λ值（００６６０和０１７４７）和ｒ值（０９０００和０９２３７）；４ｄＢＷＧ，６ｄＢＷＧ和６ｄＴＥＷ法测得ｒｈＧＨ的效价为４６１３２，３９８２９和４８０２３ＩＵ／ａｍｐ．６ｄＢＷＧ法有较小的λ值和较低的ＡＲＦＬ值．结论：可在同一组去垂体大鼠体内同时用４ｄＢＷＧ，６ｄＢＷＧ和６ｄＴＥＷ法测ＧＨ活性，以６ｄＢＷＧ法较好．     

The effect of pimozide on variable-interval performance: A test of the ‘anhedonia’ hypothesis of the mode of action of neuroleptics

A quantitative behavioural test system based on Herrnstein's (1970) equation was used to test a prediction derived from the anhedonia hypothesis of neuroleptic action, that pimozide should increase the value of the behavioural parameter K _H (the reinforcement frequency needed to maintain the half-maximal response rate in variable-interval schedules). On the basis of theoretical considerations, it was shown that the equation implies that a drug which exerts such an effect on K _H must have a more profound suppressant effect on performance maintained by low reinforcement frequencies than on performance maintained by high reinforcement frequencies. Fifteen rats were trained under variable-interval 10-s and variable-interval 100-s schedules, and the effect of pimozide (0.125, 0.25, 0.33, and 0.5 mg/kg) was tested on performance maintained under each schedule. The drug suppressed performance maintained under both schedules in a dose-dependent manner, and there was no tendency for the drug to exert a greater effect on performance maintained under the lower reinforcement frequency. These results do not provide any evidence that the effect of pimozide on variable-interval performance is due to an anti-hedonic effect; rather, they are compatible with the hypothesis that pimozide impairs the capacity to respond.     

Tonic potentiation and attenuation produced by membrane depolarization in guinea-pig trachealis

1. We studied how membrane depolarization directly affected intracellular Ca2+ signalling when voltage-operated Ca2+ channels (VOCC) were not available in guinea-pig tracheal smooth muscle. To block VOCC, we used 3 micromol/L verapamil, which completely abolished high K+ (20-60 mmol/L)-induced contraction, and elevation of fura-2 signal. 2. Muscle tone was generated by adding Ca2+ to the extracellular Ca2+-free solution containing prostaglandin (PG)E2 (100 nmol/L) after abolishing basal tone with indomethacin (1 micromol/L). 3. In the absence of verapamil, high K+ (20-60 mmol/L) solution potentiated 2.4 mmol/l Ca2+-induced sustained contractions. Even in the presence of 3 micromol/L verapamil, replacement with 20 and 40 mmol/L K+ solution induced tonic potentiation, which was changed to attenuation with a higher K+ solution (60 mmol/L), lower extracellular Ca2+ concentration ([Ca2+]o) and pretreatment with cyclopiazonic acid (10 micromol/L), a Ca2+ sequestration inhibitor. 4. These results indicate that the balance between depolarization-dependent Ca2+ release and receptor-operated cation channel inhibition may determine whether tonic potentiation or attenuation is manifested, depending on the availability of VOCC, the magnitude of the depolarization, [Ca2+]o and Ca2+ content in the sarcoplasmic reticulum.     

TRPC channels: integrators of multiple cellular signals

TRPC channels are ubiquitously expressed among cell types and mediate signals in response to phospholipase C (PLC)-coupled receptors. TRPC channels function as integrators of multiple signals resulting from receptor-induced PLC activation, which catalyzes the breakdown of phosphatidylinositol 4,5-bisphosphate (PIP2) to produce inositol 1,4,5-trisphosphate (InsP3) and diacylglycerol (DAG). InsP3 depletes Ca2+ stores and TRPC3 channels can be activated by store-depletion. InsP3 also activates the InsP3 receptor, which may undergo direct interactions with the TRPC3 channel, perhaps mediating store-dependence. The other PLC product, DAG, has a direct non-PKC-dependent activating role on TRPC3 channels likely by direct binding. DAG also has profound effects on the TRPC3 channel through PKC. Thus PKC is a powerful inhibitor of most TRPC channels and DAG is a dual regulator of the TRPC3 channel. PLC-mediated DAG results in rapid channel opening followed later by a slower DAG-induced PKC-mediated deactivation of the channel. The decreased level of PIP2 from PLC activation also has an important modifying action on TRPC3 channels. Thus, the TRPC3 channel and PLCgamma form an intermolecular PH domain that has high specificity for binding PIP2. This interaction allows the channel to be retained within the plasma membrane, a further operational control factor for TRPC3. As nonselective cation channels, TRPC channel opening results in the entry of both Na+ and Ca2+ ions. Thus, while they may mediate Ca2+ entry signals, TRPC channels are also powerful modifiers of membrane potential.     

粉防己碱对培养乳牛基底动脉平滑肌细胞内游离钙浓度的影响

目的：研究粉防己碱对培养乳牛基底动脉平滑肌细胞游离钙浓度（[Ca^2 ]i)的影响。方法：利用AR－CM－MIC阳离子测定系统,采用Fura 2-AM为指示剂,测量单个细胞内[Ca^2 ]i。结果：粉防己碱10－100μmol/L对培养乳牛基底动脉平滑肌细胞静息[Ca^2 ]i无明显影响。在细胞外钙为1．3mmol/L,粉防己碱可浓度依赖性地抑制KC1引起[Ca^2 ]i的升高。咖啡因10mmol/L可诱导一次[Ca^2 ]i瞬间快速升高,随后自发回复到静息水平,粉防己碱10和30μmol/L对咖啡因诱导的[Ca^2 ]i瞬间升高没有作用,但高浓度（100μmol/L）粉防己碱抑制了[Ca^2 ]i瞬间升高。在细胞外钙为1.3mmol/L,苯肾上腺素10μmol/L可引起双相[Ca^2 ]i变化,包括快速升高相和持续升高相。在细胞外钙为零,苯肾上腺素仅引起[Ca^2 ]i的快速升高相。粉防己碱可浓度依赖性地抑制苯肾上腺素引起[Ca^2 ]i快速升高相。结论：在培养乳牛基底动脉平滑肌细胞,粉防己碱可能通过影响电压依赖性和苯肾上腺素受体介导的钙通道而抑制钙内流。高浓度粉防己碱也可能影响肌浆网钙释放或钙摄取。     

胞内钙动员在硝普钠增加豚鼠胃窦环行肌细胞钙激活钾电流中的作用

AIM: To investigate the role of calcium mobilization in the calcium-activated potassium currents [IK(ca)] increasedby sodium nitroprusside (SNP), a nitric oxide (NO) donor, in gastric antral circular myocytes of the guinea pig.METHODS- A perforated patch-clamp technique was used, and the myocytes were isolated by collagenase.RESULTS: SNP 100 lamol/L significantly increased IK(Ca), and enhanced the spontaneous transient outward currents (STOC). SNP-induced increase of IK(Ca) was not blocked by extracellular calcium-free solution (containingegtazic acid 10μmol/L and nicardipine 5μmol/L, an L-type calcium channel blocker. And SNP 100μmol/Lsuppressed the L-type calcium currents (Ica). SNP-induced increase of STOC was inhibited by heparin 3g/L, apotent inhibitor of inositol triphosphate receptor (InsP3R). However, ryanodine 10μrnol/L, an inhibitor of calciuminduced calcium release (CICR), did not inhibit the effect of SNP-induced increase of STOC. Methylene blue (1μmol/L), an inhibitor of soluble guanylate cyclase, also inhibited such an effect. CONCLUSION: The increase ofIK(Ca) caused by SNP may be mediated by cGMP via IP3-sensitive calcium pools, however, extracellular Ca^2^ maynot be involved in the process.     

TRPC7

Canonical transient receptor potential7 (TRPC7) is the seventh identified member of the mammalian TRPC channel family, comprising nonselective cation channels activated through the phospholipase C (PLC) signaling pathway. TRPC7 is directly activated by diacylglycerol (DAG), one of the PLC products, having high sequence homologywith TRPC3 and TRPC6, which are also activated by DAG. TRPC7 shows unique properties of activation, such as constitutive activity and susceptibility to negative regulation by extracellular Ca2+. Although the physiological importance of TRPC7 in the native environment remains elusive, TRPC7 would play important roles in Ca2+ signaling pathway through these characteristic features.     

Mechanism of inhibition of TRPC cation channels by 2-aminoethoxydiphenylborane

We investigated the actions of the organoborane, 2-aminoethoxydiphenylborane (2APB), on Ca2+ signaling in wild-type human embryonic kidney (HEK) 293 cells and in HEK293 cells stably expressing canonical transient receptor potential (TRPC) channels. Previous reports have suggested that 2APB inhibits agonist activation of TRPC channels because of its ability to act as a membrane-permeant inhibitor of inositol 1,4,5-trisphosphate (IP3) receptors. 2APB was specifically said to inhibit TRPC3 channels when activated through a phospholipase C-linked receptor but not when activated more directly by a synthetic diacylglycerol, oleyl-acetyl-glycerol (OAG) [Science (Wash DC) 287:1647-1651, 2000]. However, we subsequently reported that IP3 does not activate TRPC3; rather the mechanism of activation by phospholipase C-linked receptors seemed to result from diacylglycerol [J Biol Chem 278:16244-16252, 2003]. Thus, the current study was carried out to address the mechanism of action of 2APB in inhibiting TRPC channels. We found that, although the release of Ca2+ by a muscarinic agonist was reduced by high concentrations of 2APB, this effect was indistinguishable from that seen when stores were discharged by thapsigargin, which does not involve IP3 receptors. This indicates that 2APB is incapable of significant inhibition of IP3 receptors when applied to intact cells. We found that 2APB partially inhibits divalent cation entry in cells expressing TRPC3, TRPC6, or TRPC7 and that this partial inhibition was observed whether the channels were activated by a muscarinic agonist or by OAG. Thus, as concluded for store-operated channels, 2APB seems to inhibit TRPC channels by a direct mechanism not involving IP3 receptors.     

Green tea catechins evoke a phasic contraction in rat aorta via H2O2-mediated multiple-signalling pathways

1. The contractile effects of tea polyphenols (TP) and its four principle catechins, namely (-)-epicatechin (EC), (-)-epicatechin-3-gallate (ECG), (-)-epigallocatechin (EGC) and (-)-epigallocatechin-3-gallate (EGCG), on rat aorta contractility were investigated using the isometric tension recording technique. 2. At concentrations of 5-100 mg/L, TP evoked phasic contraction of rat aorta in a concentration-dependent but endothelium-independent manner. Of the four catechins tested, EGCG and EGC (3-300 micromol/L), but not EC and ECG, mimicked the contractile response to TP, suggesting that the epigallol moiety in the B ring may be associated with the contractile effect. 3. Contractions in response to EGCG and EGC were not affected by several endogenous vasoconstrictor receptor antagonists, but could be abolished by 10 micro mol/L BAPTA-AM, a membrane-permeable Ca2+ chelator, or attenuated by removal of extracellular Ca2+, suggesting the involvement of both intracellular and extracellular Ca2+ in evoking the contraction. 4. Pretreatment with non-selective Ca2+ channel antagonists mefenamic acid (10 micro mol/L), tetrandrine (30 micro mol/L) and SKF 96365 (30 micromol/L), but not nifedipine (1 micromol/L), the selective inhibitor of voltage-dependent Ca2+ channels, inhibited the contractile responses to EGC and EGCG, indicating the involvement of Ca2+ influx via non-voltage dependent Ca2+ channels. 5. Several intracellular Ca2+ channel modulators, including procaine (5 mmol/L), dantrolene (30 micromol/L) and 2-amino ethoxydiphenyl borate (50 micromol/L; an inositol 1,4,5-trisphosphate receptor inhibitor), also inhibited EGCG- and EGC-induced contractions, thus suggesting a role of intracellular Ca2+ release in these contractions. 6. Both EGCG- and EGC-induced contractions were depressed, to different degrees, by inhibitors of several receptor-coupled enzymes, including phospholipase C, protein kinase C, phospholipase A2 and tyrosine kinase. Furthermore, both EGCG- and EGC-induced contractions were completely abolished by catalase, but not by superoxide dismutase or mannitol/dimethyl sulphoxide. 7. Taken together, these data show, for the first time, that TP and its related catechins that contain an epigallol structure in the B ring, as in EGCG and EGC, exert direct contractile effects on rat aortic smooth muscle via a H2O2-mediated pathway.     

氟哌啶醇季铵盐衍生物抑制氯化钾所致大鼠主动脉平滑肌细胞内钙浓度增加

目的:动态观察氟哌啶醇季铵盐衍生物(F_3)对血管平滑肌细胞内钙浓度的影响。方法:利用激光共聚焦显微镜动态观察F_3(0.o1-10μmol/L)对由KCl(30mmol/L)诱导的大鼠血管平滑肌细胞钙荧光强度增加的作用。结果:KCl可诱发细胞内钙荧光强度迅速增强,F_3可以拮抗由KCl诱导的细胞内钙荧光强度增强作用,并呈量效依赖性和时间依赖性,终强度(KCl:67±24;F_3 0.o1μmol/L:57±13;0.1μmol/L:40±13;1μmol/L:29±9;10μmol/L:20±6)。在加入F_3后,钙荧光强度的变化最快时程是在给F_3后0-30s。结论:F_3拮抗血管收缩主要是由于阻断了Ca~(2 )通道。     

Effect of calcium on the vascular contraction induced by cobra venom cardiotoxin

1. The cytotoxic effects of cardiotoxin (CTX) purified from Cobra venom were tested in endothelium-denuded rat aortic ring preparations in tissue organ baths and the effect of extracellular Ca2+ on the cytotoxic effect of CTX was investigated using a digital dynamic calcium imaging technique. 2. At 10 micromol/L, CTX induced a slowly developing and sustained contraction that amounted to approximately 50% of the maximal contraction induced by 80 mmol/L KCl. At high concentrations (> 15 micromol/L), CTX caused irreversible damage to the smooth muscle contractile function. However, washout of CTX at its peak contraction did not affect the subsequent contraction to either KCl or phenylephrine. 3. Contraction induced by CTX was dependent on the Ca2+ concentration in the external solution. A maximal contractile response to CTX was obtained in medium containing 1-2.5 mmol/L Ca2+. This contractile response induced by CTX decreased with higher Ca2+ concentrations and was completely diminished when 7 mmol/L Ca2+, 3 mmol/L Ni2+ or 30 micromol/L tetrandrine (a non-selective calcium channel blocker) was present in the external solution before addition of CTX to the bath. 4. The above observations were supported by the calcium imaging work performed with cultured aortic smooth muscle cells from Wistar-Kyoto rats, in which CTX was shown to induce the elevation of cytosolic Ca2+ in the presence, but not in the absence, of 2.5 mmol/L extracellular Ca2+. Increasing the extracellular Ca2+ concentration to 7 mmol/L, the addition of 3 mmol/L Ni2+ or inclusion of 30 micro mol/L tetrandrine inhibited the elevation of cytosolic Ca2+ induced by CTX. 5. These results suggest that: (i) a CTX-sensitive internal calcium store does not exist in rat aortic smooth muscle; (ii) the contractile effect CTX is associated with a Ca2+ influx process; and (iii) CTX interacts extracellularly with the plasma membrane at the level of the calcium channels, as well as anionic sites to which Ca2+ and other inorganic cations bind.     

Fendiline mobilizes intracellular Ca2+ in Chang liver cells

1. The effects of the antianginal drug fendiline (N-[3,3-diphenylpropyl]-alpha-methyl-benzylamine) on intracellular free Ca2+ levels ([Ca2+](i)) in Chang liver cells were evaluated using fura-2 as a fluorescent Ca2+ indicator. 2. Fendiline (1-100 micromol/L) increased [Ca2+](i) in a concentration-dependent manner, with an EC50 of 25 micromol/L. 3. The [Ca2+](i) response was composed of an initial rise and a slow decay to a sustained phase. Removal of extracellular Ca2+ partly reduced the [Ca2+](i) signals. 4. Fendiline (10 micromol/L)-induced release of intracellular Ca2+ was reduced by 65% following pretreatment with 1 micromol/L thapsigargin (an endoplasmic reticulum Ca2+ pump inhibitor) to deplete Ca2+ stored in the endoplasmic reticulum. 5. After pretreatment with 10 micromol/L fendiline in Ca2+-free medium for several minutes, addition of 3 mmol/L Ca2+ induced an increase in [Ca2+](i) of a magnitude four-fold greater than control. This increase in [Ca2+](i) was not reduced by 10 micromol/L SKF96365, econazole, nifedipine or verapamil. 6. Fendiline (10 micromol/L)-induced release of intracellular Ca2+ was not altered by inhibition of phospholipase C with 2 micromol/L 1-(6-((17beta-3-methoxyestra-1,3,5(10)-trien-17-yl)amino) hexyl)-1H-pyrrole-2,5-dione (U73122). 7. The results of the present study show that fendiline induces an increase in [Ca2+](i) in Chang liver cells by releasing stored Ca2+ in an inositol 1,4,5-trisphosphate-independent manner and by causing extracellular Ca2+ influx.