葛根素和大豆甙元抑制[3H]氟硝西泮和体外大鼠脑膜的结合

从中药葛根中提取到两种苯二氮艹卓受体活性化合物:葛根素和大豆甙元。两种化合物在体外可抑制[3H]氟硝西泮和大鼠脑细胞膜的结合,IC₅₀值分别为18.46μmol·L^-1和15.43μmol·L^-1。大豆甙元还可抑制[³H]哌唑嗪和α1-肾上腺素受体的结合(IC₅₀值为89μmol·L^-1)。两种化合物的GABA比分别为1.11和1.12,提示两种黄酮化合物是苯二氮艹卓受体的拮抗剂或部分激动剂。Scatchardplot分析显示:两种化合物对[³H]氟硝西泮与膜结合的抑制作用是通过竞争性与非竞争性混合机制而实现的。     

从阿拉伯艾蒿分离到两种对苯并二氮杂和α_1肾上腺素能受体有亲和力的黄酮化合物(英文)

干燥阿拉伯艾蒿的酒精提取物对体外[~3H]地西泮和大鼠大脑皮质细胞膜结合产生抑制作用,两种化合物被分离纯化,其化学结构为毛地黄黄酮和玄参黄酮(IC_(50)分别为1.3±s0.1和22.7±S2.5μmol·L~1),两种化合物在体外还能抑制[~3H]哌唑嗪和大鼠脑皮质细胞膜结合,但不能改变[~3H]蝇蕈碱乙酰胆碱受体,[~3H]蝇蕈醇,[~3H]SCH 23390和[~3H]螺哌隆和膜的结合,Scatchard plot分析提示两种化合物对[~3H]地西泮和膜结合的抑制作用是通过竟争性和非竞争性混合机理而实现的。     

常用中药单体及其制剂对CYP3A活性的体外抑制作用研究

摘 要 目的:研究常用中药单体及其制剂对CYP3A活性的抑制作用。方法: 在体外肝微粒体孵育体系中加入底物睾酮和不同浓度的中药单体或其制剂,以高效液相色谱法检测6β羟基睾酮的生成量,计算CYP3A酶活性。用GraphPad Prism v5.0软件,按照非线性回归计算出药物对CYP3A抑制作用的IC₅₀值。结果:不同中药单体及其制剂对CYP3A抑制作用的IC₅₀值如下：大黄酸IC₅₀值为36.74 μmol·L^-1;大黄素IC₅₀值为23.09 μmol·L^-1、芦荟大黄素IC₅₀值为23.91 μmol·L^-1,蜂胶IC₅₀值为60.3 μg·mL^-1;水飞蓟素胶囊IC₅₀值为24.5μg·mL^-1;丹参酮ⅡA磺酸钠注射液IC₅₀值为0.14%(v/v);五味子酯甲IC₅₀值为0.56 μmol·L^-1。结论: 大黄中的蒽醌、五味子酯甲、蜂胶、水飞蓟胶囊以及丹参酮ⅡA磺酸钠注射液在体外对鼠或人肝CYP3A酶具有抑制作用,临床上使用相关制剂时应密切关注其可能引起的药物相互作用。     

红花黄酮成分抑制血小板激活因子介导的血小板活化作用

目的　观察红花黄酮成分杨梅素(Myr)和山奈酚(Kae)对血小板激活因子(PAF)诱导的兔洗涤血小板聚集、5 HT释放及血小板内游离钙离子浓度升高的影响。方法　以比浊法测定家兔洗涤血小板(WRP)聚集,邻苯二甲醛(OPT)荧光法测定5-HT浓度,Fura-2荧光探针测定血小板内游离钙离子浓度。结果　Myr和Kae体外呈浓度依赖性地抑制PAF诱发的WRP聚集及5-HT释放。Myr抑制WRP聚集的IC₅₀ 为17.5 μmol·L^-1 ;抑制5-HT释放的IC₅₀ 为64.1μmol·L^-1 。Kae抑制聚集、释放作用的IC₅₀ 分别为73.7μmol·L^-1 和128μmol·L^-1 ;同时Myr和Kae均能明显抑制PAF引起的血小板内游离钙增高。结论　Myr和Kae可抑制PAF诱导的血小板活化作用     

和厚朴酚、厚朴酚、栀子苷、绿原酸和黄芪甲苷对人和大鼠体外CYP1A2、CYP3A和CYP2D的抑制作用

目的 观察和厚朴酚、厚朴酚、栀子苷、绿原酸和黄芪甲苷5种中药成分体外对人和大鼠肝CYP1A2、CYP3A和CYP2D的抑制作用。方法 在人和大鼠肝微粒体孵育体系中,分别以非那西丁、咪达唑仑和右美沙芬为探针,应用HPLC检测受试物对探针代谢产物生成量的影响,评估5种中药成分对CYP1A2、CYP3A和CYP2D在该体系中的活性影响,并计算得到抑制率和IC₅₀。结果 和厚朴酚对人和大鼠CYP1A2、CYP2D的IC₅₀值分别为5.5、3.9、35.3和46.7 μmol·L^-1;厚朴酚对人CYP1A2、大鼠CYP1A2和CYP2D的IC50值分别为23.8,29.1和39.9 μmol·L^-1;栀子苷、绿原酸和黄芪甲苷对3种CYP酶亚型的IC₅₀均>100 μmol·L^-1;和厚朴酚对人和大鼠CYP3A的IC₅₀均>100 μmol·L^-1;厚朴酚对人CYP3A、CYP2D和大鼠CYP3A的IC₅₀均>100 μmol·L^-1。结论 和厚朴酚体外对人和大鼠CYP1A2和CYP2D有抑制作用,厚朴酚体外对人CYP1A2、大鼠CYP1A2和CYP2D有抑制作用,均呈浓度依赖性。     

小檗碱对培养大鼠神经细胞内游离Ca2+的影响

以Fura-2/AM为细胞内钙离子的荧光指示剂,用AR-CM-MIC阳离子测定系统,直接测定了体外培养的新生大鼠神经细胞内游离钙([Ca²⁺]i)值,并观察了小檗碱(Ber)的影响。结果表明,Ber对神经细胞静息[Ca²⁺]i无明显影响,Ber1～100μmol·L^-1能剂量依赖地抑制去甲肾上腺素和H₂O₂引起的[Ca²⁺]i升高,其IC₅₀分别为39.9和17.9μmol·L^-1。高剂量Ber(10～100μmol·L^-1)能抑制高K+引起的[Ca²⁺]i升高。姐果提示,Ber对去甲肾上腺素,高K⁺及H₂O₂引起的[Ca²⁺]i升高的抑制作用可能是其抗脑缺血作用机制之一。     

二茂铁杂环类化合物的合成及抗三阴性乳腺癌活性研究

目的 设计、合成杂环二茂铁衍生物,并研究其抗三阴性乳腺癌活性。方法 以二茂铁查耳酮为先导化合物,对其进行结构改造,合成了一系列含有杂环的二茂铁衍生物,并通过CCK8试剂盒测试化合物抗乳腺癌活性。结果 合成了28个二茂铁衍生物,其结构均通过¹H-NMR和MS加以确证。初步的生物活性测试结果表明,所合成的二茂铁衍生物对三阴性乳腺癌MDA-MB-231细胞有较强的选择性和抑制活性,其中咪唑杂环化合物抗肿瘤活性强于相应的吡唑类和嘧啶化合物。尤其是28a[IC₅₀=（1.6±0.23）μmol·L^-1]对MDA-MB-231的抑制活性分别是先导化合物3[IC₅₀=（10.7±1.41）μmol·L^-1]和他莫昔芬[IC₅₀=（13.7±1.17）μmol·L^-1]的6和10倍,同时这些二茂铁衍生物对正常乳腺上皮细胞MCF-10A均没有毒性。结论 本研究为开发具有抗三阴性乳腺癌活性的化合物提供了信息和依据。     

四肽FMRFa对大鼠心室肌Na+/Ca2+交换的抑制

目的　研究四肽FMRFa对大鼠单个心室肌细胞Na⁺/Ca²⁺交换的作用。方法　用膜片钳全细胞记录法测定成年大鼠心室肌细胞Na⁺/Ca²⁺交换电流(I_Na⁺/Ca²⁺)和其他离子通道电流。结果　FMRFa对大鼠心室肌细胞I_Na⁺/Ca²⁺呈浓度依赖性抑制,100μmol·L^-1浓度时抑制内向和外向I_Na⁺/Ca²⁺密度分别达60.1%和56.5%,对内向电流及外向电流的IC₅₀分别为20μmol·L^-1和34μmol·L^-1。FMRFa5μmol·L^-1抑制I_Na⁺/Ca²⁺内向和外向电流密度分别为38.7%和34.9%,但FMRFa5μmol·L^-1及20μmol·L^-1对L型钙电流、钠电流、瞬时外向电流和内向整流钾电流均无显著抑制作用。结论　FMRFa对大鼠心室肌细胞是一个特异性Na⁺/Ca²⁺交换抑制剂。     

III类抗心律失常药RP58866对豚鼠及犬内向整流及瞬时外向钾电流的作用

目的:研究III类抗心律失常药RP58866 对I_K1 ,瞬时外向钾电流(Ito) 的作用。方法:用豚鼠和犬离体心肌细胞及全细胞电压钳技术。结果:在- 100 m V 时,RP58866 以浓度依赖方式明显减少了豚鼠心室肌细胞I_K1,其IC₅₀为(3-4±0-8) μmol·L^-1。在犬心室肌细胞,RP58866 可明显抑制Ito( 在100 μmol·L^-1 时减少87% ±2-1% ),其IC₅₀为(2-3±0-5) μmol·L^-1 。结论:RP58866 对心肌细胞的IK1 和Ito 均有抑制作用,而不是一种特殊的IK1抑制剂。     

Loss of dopamine D1-like receptors in the umbilical artery of pre-eclamptic subjects

1 The influence of pre-eclampsia on the density and pattern of dopamine D₁-like receptors was studied in frozen samples of the placental end of the umbilical artery by using radioligand binding and autoradiographic techniques in combination. 2 Analysis was performed on normotensive (n= 10) and pre-eclamptic subjects (n= 9) undergoing caesarean delivery, using [³H]-SCH 23390 as a ligand. Pre-eclamptic patients received a low salt diet and were treated with magnesium sulphate and hydralazine. The possibility that this treatment may cause changes in the density of dopamine D₁-like receptors was evaluated by treating male Wistar rats in the same way and by determining [³H]-SCH 23390 binding in sections of the kidney which represents an organ containing dopamine D₁-like receptors. 3 The density of dopamine D₁-like receptors of the umbilical artery, which are probably vasodilatory, was decreased in pre-eclamptic compared with normotensive subjects. In contrast, the affinity of the radioligand for dopamine D₁-like receptors was not statistically different between normotensive and pre-eclamptic subjects. Low salt diet, magnesium sulphate and hydralazine treatment did not affect [³H]-SCH 23390 binding to sections of rat kidney. This suggests that changes in the density of dopamine D₁-like receptors in pre-eclamptic patients are a specific phenomenon not dependent upon antihypertensive measures. 4 Analysis of the pharmacological profile of [³H]-SCH 23390 binding to sections of the umbilical artery both in normotensive and pre-eclamptic subjects indicates the labelling of dopamine D₅ receptors. 5 These findings collectively suggest that the dopaminergic vasodilatory tone in the umbilical artery is impaired in pre-eclampsia. The possible significance of these data should be clarified in future studies.     

Investigation of rat striatal dopamine D-1 receptors solubilized by digitonin with a precipitation method

[3H]SCH 23390 binding sites solubilized from rat striatal membranes by the detergent digitonin were investigated by using a polyethylene glycol precipitation method to separate the bound [3H]SCH 23390 from the free [3H]SCH 23390. The binding of [3H]SCH 23390 to the solubilized preparations was specific and saturable with a KD of 4.99 +/- 0.03 nM and a Bmax of 619 +/- 13 fmol/mg protein. The rank order of potency of dopamine agonists and antagonists for competing with [3H]SCH 23390 binding for the solubilized preparations was appropriate for dopamine D-1 receptors. The competition of SCH 23390 and S(-)-SCH 23388 with [3H]SCH 23390 binding for the solubilized preparations was stereoselective. However, the sensitivity of the dopamine agonist high-affinity binding to guanine nucleotide GTP was almost lost upon digitonin solubilization. Preincubating the membranes with dopamine preserved the guanine nucleotide sensitivity of agonist binding for membranes in solubilized preparations. These results proved that the polyethylene glycol precipitation method can be used for assay of digitonin-solubilized dopamine D-1 receptors in rat striatum.     

Direct demonstration of dopamine D1-like receptor sites in the ciliary body of the rabbit eye by light microscope autoradiography

Summary The pharmacological characteristics and the anatomical localization of [³H]-SCH 23390 in sections of the ciliary body of the rabbit eye were analyzed using a radioreceptor assay and autoradiographic techniques. [³H]-SCH 23390 was bound to sections of rabbit ciliary body in a manner consistent with the labelling of D₁-like receptor sites. The dissociation constant (K _d) was 0.62 nmol/l, while the maximum binding capacity (B_max) was 117 ± 9 fmol/mg tissue.Light microscope autoradiography revealed [³H]-SCH 23390 binding sites within the epithelium of the ciliary processes, which is the ocular structure involved in the secretion of aqueous humor. No specific accumulation of silver grains was noticeable within the iridocorneal angle, which is the structure involved in the outflow of aqueous humor. These findings suggest that the rise in intraocular pressure caused by D₁ receptor agonists is probably mediated by an increase of aqueous humor formation rather than by an inhibition of the outflow of aqueous humor.     

Sodium dependent [3H]cocaine binding associated with dopamine uptake sites in the rat striatum and human putamen decrease after dopaminergic denervation and in Parkinsons disease

Summary The binding of radiolabelled cocaine, an inhibitor of dopamine uptake, to the post-mortem human putamen was studied and compared to that in the rat striatum. Saturation analysis of [³H]cocaine binding to the human putamen revealed the presence of a high affinity component of binding with a K _d of 0.21 mol/l and a B _max of 1.47 pmol/mg protein. In addition a low affinity component (K _d=26.4 mol/l) was demonstrated, having a B _max of 42.2 pmol/mg protein. Also in the rat striatum [³H]cocaine binding was both of high affinity (K _d=0.36 mol/l, B _max=5.56 pmol/mg protein) and low affinity (K _d=25.9 mol/l, B _max=35.6 pmol/mg protein). A pharmacological characterisation of high affinity [³H]cocaine binding to rat striatal membranes clearly indicates an association with the neuronal dopamine transporter. The IC₅₀ values of 8 selected drugs for inhibition of [³H]cocaine binding in the rat striatum were highly significantly correlated with their potency to inhibit [³H]dopamine uptake into slices of the rat striatum. [³H]Cocaine binding was stereospecifically inhibited by (+)nomifensine and (+)diclofensine which were 50–80-fold more active than their respective (-)isomers. Drugs with dopamine releasing activity were more potent at inhibiting [³H]dopamine uptake than at competing for the high affinity site of [³H]cocaine binding. A highly significant correlation was found between IC₅₀ values for [³H]cocaine binding in the rat striatum and the human putamen. Further evidence in support of an association of [³H]cocaine binding in the rat striatum with the dopamine transporter was obtained from lesion studies. Thus, intranigral 6-hydroxydopamine administration produced a marked (67%) decrease in striatal [³H]cocaine binding. Also in the human putamen high affinity [³H]cocaine binding sites appear localized on dopaminergic nerve terminals as evidenced by a prominent decrease in binding in the putamen obtained from subjects with Parkinsons disease. It is concluded that [³H]cocaine may be a useful ligand to examine the dopamine transporter in the rat striatum and the human putamen. Therefore it offers a new and valuable approach in the study of drug effects and neuropsychiatric diseases.Preliminary results on some parts of this study have appeared previously in abstract form (Langer et al. 1984a) or as a rapid communication (Pimoule et al. 1983)     

Interaction of mephedrone with dopamine and serotonin targets in rats

IntroductionWe described a first approach to the pharmacological targets of mephedrone (4-methyl-methcathinone) in rats to establish the basis of the mechanism of action of this drug of abuse.Experimental proceduresWe performed in vitro experiments in isolated synaptosomes or tissue membrane preparations from rat cortex or striatum, studying the effect of mephedrone on monoamine uptake and the displacement of several specific radioligands by this drug.ResultsIn isolated synaptosomes from rat cortex or striatum, mephedrone inhibited the uptake of serotonin (5-HT) with an IC₅₀ value lower than that of dopamine (DA) uptake (IC₅₀ = 0.31 ± 0.08 and 0.97 ± 0.05 μM, respectively). Moreover, mephedrone displaced competitively both [³H]paroxetine and [³H]WIN35428 binding in a concentration-dependent manner (Ki values of 17.55 ± 0.78 μM and 1.53 ± 0.47 μM, respectively), indicating a greater affinity for DA than for 5-HT membrane transporters. The affinity profile of mephedrone for the 5-HT₂ and D₂ receptors was assessed by studying [³H]ketanserin and [³H] raclopride binding in rat membranes. Mephedrone showed a greater affinity for the 5-HT₂ than for the D₂ receptors.DiscussionThese results provide evidence that mephedrone, interacting with 5-HT and DA transporters and receptors must display a similar pattern of other psychoactive drugs such as amphetamine-like compounds.     

Radioligand binding and autoradiographic analysis of dopamine receptors in the human heart

Summary The effects of dopamine on the 3-5-cyclic adenosine monophosphate (cAMP) generating system were analyzed in membrane particles from the human right and left cardiac ventricle. In addition, the pharmacological profile and the anatomical localization of dopamine receptors were assessed on frozen sections of human cardiac atrial or ventricular tissue. Dopamine increased cAMP levels, in a concentration-dependent manner, in membranes of the right and the left ventricle. These effects were abolished by the -adrenoceptor antagonist (–)-propranolol, but not by the D₁ receptor antagonist SCH 23390 or by the non selective D₁/D₂ receptor antagonist haloperidol.No specific binding of the D₁ receptor antagonist [³H]-SCH 23390 was noticeable within the atrial or ventricular portions of the heart examined using either radioligand binding or autoradiographic techniques. The D₂ receptor antagonist [³H]-spiroperidol, in the presence of concentrations of ketanserin sufficient to block possible binding to 5-HT₂ sites, was specifically bound to sections of human heart with a dissociation constant value of about 2.6 nmol/l. The highest density of [³H]-spiroperidol binding occurred in the right ventricle followed, in descending order, by the right atrium, the upper part of the left ventricle, the lower part of the left ventricle, the left atrium and the interventricular septum. The binding profile of [³H]-spiroperidol to sections of human heart was consistent with the labeling of dopamine D₂ sites. Light microscope autoradiography revealed silver grains throughout the atrial and ventricular walls and these were frequently accumulated in clusters. These findings suggest that the cardiac actions of dopamine are mediated through the activation of -adrenoceptors and of dopamine D₂ receptors but not of D₁ receptors.     

Identification of non-serotonergic [3H]ketanserin binding sites on human platelets and their role in serotonin release

[³H]Ketanserin was found to label (besides a low amount of 5-HT₂ receptors) non-serptonergic binding sites on human platelet membranes. The latter binding was detected in the presence of excess of the 5-HT₂ antagonist BW501, and was potently inhibited by tetrabenazine. [³H]Ketanserin revealed a K_D value = 19 ± 4 nM and a B_max = 425 ± 82 fmol/10⁹ platelets for these binding sites. [³H]Ketanserin binding in the presence of BW501 was inhibited by the tetrabenazine derivative RO-4-1284 (IC₅₀ = 1.4 nM), tetrabenazine (IC₅₀ = 8.6 nM) and the ketanserin derivatives R 71 278 (IC₅₀ = 6.3 nM). R 47 288 (IC₅₀ = 17 nM) and R 71 428 (IC₅₀ = 100 nM). Ketanserin revealed an IC₅₀ = 32 nM. The drugs were found to trigger the release of ³H from [³H]5-HT-loaded human platelets in superfusion experiments in vitro. The amount of ³H released by the drugs correlated with their binding affinities for the non-serotonergic sites. The non-serotonergic [³H]ketanserin binding sites on human platelets and their possible role in triggering monoamine release corresponded to the properties of non-serotonergic ketanserin binding sites previously characterized in rat striatum. The possible role of the action of ketanserin on the non-serotonergic sites in the reported partial reduction by ketanserin of the monoamine content in cardiovascular tissues is discussed.     

The effect of amperozide on uptake and release of [3H]-dopamine in vitro from perfused rat striatal and limbic brain areas

Amperozide, a putatively antipsychotic drug, was studied for its effects on uptake and release of [³H]-dopamine in rat brain in vitro. Amperozide inhibited uptake of [³H]-dopamine in striatal chopped tissue in vitro with an IC₅₀ of 18 μM. It also increased basal release of [³H]-dopamine from perfused rat striatal and limbic tissue in vitro at concentrations above 5 μM. Release of [³H]-dopamine from perfused rat striatal and limbic tissue stimulated with 5 μM amphetamine, was inhibited by 1 μM amperozide to 46%. No significant difference was found for the effect of amperozide on in vitro release of [³H]-dopamine from corpus striatum compared to tissue from limbic brain regions; neither on basal release nor on amphetamine-stimulated release of dopamine.     

Effects of ceruletide on the dopamine receptor-adenylate cyclase system in striatum and frontal cortex of rats chronically treated with haloperidol

Chronic treatment of rats with haloperidol decanoate (30 mg/kg and 100 mg/kg IM every 4 weeks for 52 weeks) increased [³H] SCH 23390 binding in striatal membranes by 25% and 50% and in frontal cortical membranes by 56% and 125% in 30 and 100 mg/kg haloperidol treatment groups, respectively. These increases in [³H] SCH 23390 binding to the membranes were restored to control levels after ceruletide treatment (100 µg/kg IP twice a day for 5 days). [³H] Spiperone binding to the rat striatal and cortical membranes also increased after chronic haloperidol treatment (by 66% and 99% in striatal membranes and by 27% and 62% in cortical membranes in the 30 and 100 mg/kg haloperidol treatment groups, respectively). Administration of ceruletide to haloperidol-treated rats reduced the increased [³H] spiperone binding to the cortical membranes toward the control level, but ceruletide was not effective in reducing the haloperidol-induced increase of [³H] spiperone binding to the striatal membranes. Activation of adenylate cyclase by dopamine (1 µM or 100 µM) or Gpp(NH)p (1 µM) was reduced in striatal and cortical membranes from haloperidol-treated rats. Ceruletide restored the lowered level of dopamine-stimulated or Gpp(NH)p-stimulated adenylate cyclase activity in the membranes from haloperidol-treated rats to control levels. These findings indicate that systemically administered ceruletide is capable of reversing alterations in D₁ dopamine receptor/D₁ dopamine receptor coupling to adenylate cyclase in striatum and frontal cortex induced by chronic treatment of rats with haloperidol decanoate.     

Transport properties of 3′-azido-3′-deoxythymidine and 2′,3′-dideoxyinosine in the rat choroid plexus

Transport properties of 3′-azido-3′-deoxythymidine (AZT) and 2′, 3′-dideoxyinosine (DDI) were characterized in the isolated rat choroid plexus. AZT and DDI competitively inhibited the active transport of [³H]benzylpenicillin, a prototypic organic anion, with K_i values of 85·4±13·1 and 155±22 μM, respectively. Accumulation of [³H]DDI was against an electrochemical potential via a saturable process (K_m=29·7±4·9 μM, V_max=13·5±2·4 pmol min⁻¹/μL tissue) that was inhibited by metabolic inhibitors (carbonylcyanide p -trifluoromethoxyphenylhydrazone, 10 μM, and rotenone, 30 μM) and sulphydryl reagents (p -chloromercuribenzoic acid, 100 μM, and p -chloromercuribenzenesulphonic acid, 100 μM), but did not require an inwardly directed Na⁺ gradient. Accumulation of [³H]DDI was inhibited by benzylpenicillin and AZT in a dose-dependent manner, with IC₅₀ values of 91·6±28·9 and 294±84 μM, respectively. In contrast, no significant accumulation of [³H]AZT was observed. These results suggest that DDI is transported, at least in part, by the transport system for organic anions located on the rat choroid plexus, whereas AZT is recognized, but not transported by this system. © 1997 John Wiley & Sons, Ltd.