双核Pt(Ⅳ)配合物与Guanosine-5′-Monophosphate和Glutathione反应的核磁共振光谱研究(英文)

合成了一个新型的双核Pt(Ⅳ)配合物｛[cis-Pt(NH3)2Cl(OH)2]2(4,4′-methylenedianiline)｝(NO3)2(化合物1)及相应的15N标记化合物｛[cis-Pt(15NH3)2Cl(OH)2]2(4,4′-methylenedianiline)｝(NO3)2(化合物15N-1)。利用1HNMR和ESMS进行了结构表征,化合物15N-1的2D[1H,15N]HSQCNMR发现,该化合物在水溶液中存在同分异构体。2D[1H,15N]HSQCNMR技术跟踪了化合物15N-1与Guanosine-5′-Monophosphate(5′-GMP)和Glutathione(GSH)的反应。结果显示,5′-GMP能在0.5h内将化合物1还原,而GSH在6h以后才能够部分的将化合物1还原。化合物1所表现出来的反应性能将有利于提高其治疗效果和降低毒副作用。

磷酸二酯酶5在心力衰竭中作用的研究进展

磷酸二酯酶5(PDE5)是环磷酸鸟苷(cGMP)特异性水解酶,是由一氧化氮(NO)激活的可溶性鸟苷酸环化酶(sGC)靶向cGMP产生的。PDE5催化cGMP中磷酸二酯键的水解,从而将cGMP转化为无活性的5′-GMP形式,cGMP-PKG轴功能障碍将引起心脏重塑,是心力衰竭(HF)的主要原因之一。但PDE5抑制剂治疗心力衰竭的临床疗效存在争议。本文总结了近年来PDE5在心力衰竭中的作用机制和研究进展,对未来临床应用PDE5靶向治疗心力衰竭具有重要的指导意义。

Analysis of the nitric oxide-cyclic guanosine monophosphate pathway in experimental liver cirrhosis suggests phosphodiesterase-5 as potential target to treat portal hypertension

AIM To investigate the potential effect of inhibitors of phosphodiesterase-5(PDE-5) for therapy of portal hypertension in liver cirrhosis.METHODS In the rat model of thioacetamide-induced liver fibrosis/cirrhosis the nitric oxide-cyclic guanosine monophosphate(NO-cGMP) pathway was investigated. Expression and localization of PDE-5, the enzyme that converts vasodilating cGMP into inactive 5'-GMP, was in the focus of the study. Hepatic gene expression of key components of the NO-cGMP pathway was determined by qRT-PCR: Endothelial NO synthase(eNOS), inducible NO synthase(iNOS), soluble guanylate cyclase subunits α1 and β1(sGCa1, sGCb1), and PDE-5. Hepatic PDE-5 protein expression and localization were detected by immunohistochemistry. Serum cGMP concentrations were measured using ELISA. Acute effects of the PDE-5 inhibitor Sildenafil(0.1 mg/kg or 1.0 mg/kg) on portal and systemic hemodynamics were investigated using pressure transducers.RESULTS Hepatic gene expression of eNOS(2.2-fold; P = 0.003), sGCa1(1.7-fold; P = 0.003), sGCb1(3.0-fold; P = 0.003), and PDE-5(11-fold; P = 0.003) was increased in cirrhotic livers compared to healthy livers. Overexpression of PDE-5(7.7-fold; P = 0.006) was less pronounced in fibrotic livers. iNOS expression was only detected in fibrotic and cirrhotic livers. In healthy liver, PDE-5 protein was localized primarily in zone 3 hepatocytes and to a lesser extent in perisinusoidal cells. This zonation was disturbed in cirrhosis: PDE-5 protein expression in perisinusoidal cells was induced approximately 8-fold. In addition, PDE-5-expressing cells were also found in fibrous septa. Serum cGMP concentrations were reduced in rats with cirrhotic livers by approximately 40%. Inhibition of PDE-5 by Sildenafil caused a significant increase in serum cGMP concentrations [+ 64% in healthy rats(P = 0.024), + 85% in cirrhotic rats(P = 0.018)]. Concomitantly, the portal venous pressure was reduced by 19% in rats with liver cirrhosis. CONCLUSION Overexpression and abrogated zonation of PDE-5 likely contribute to the pathogenesis of cirrhotic portal hypertension. PDE-5 inhibition may therefore be a reasonable therapeutic approach for portal hypertension.

Electroacupuncture improves neuropathic pain Adenosine, adenosine 5'-triphosphate disodium and their receptors perhaps change simultaneously

Applying a stimulating current to acupoints through acupuncture needles–known as electroacupuncture–has the potential to produce analgesic effects in human subjects and experimental animals. When acupuncture was applied in a rat model, adenosine 5-triphosphate disodium in the extracellular space was broken down into adenosine, which in turn inhibited pain transmission by means of an adenosine A1 receptor-dependent process. Direct injection of an adenosine A1 receptor agonist enhanced the analgesic effect of acupuncture. The analgesic effect of acupuncture appears to be mediated by activation of A1 receptors located on ascending nerves. In neuropathic pain, there is upregulation of P2X purinoceptor 3 （P2X3） receptor expression in dorsal root ganglion neurons. Conversely, the onset of mechanical hyperalgesia was diminished and established hyperalgesia was significantly reversed when P2X3 receptor expression was downregulated. The pathways upon which electroacupuncture appear to act are interwoven with pain pathways, and electroacupuncture stimuli converge with impulses originating from painful areas. Electroacupuncture may act via purinergic A1 and P2X3 receptors simultaneously to induce an analgesic effect on neuropathic pain.

Transformation of microstructure and phase of disodium guanosine 5′-monophosphate: Thermodynamic perspectives

Microstructure and phase transformation of disodium guanosine 5′-monophosphate(5′-GMPNa_2) are extremely important for controlling the process and understanding the mechanism of crystallization. In this work, the thermodynamic properties of polymorphous 5′-GMPNa_2 especially the solubility were studied, the solubility results show that 5′-GMPNa_2 is more soluble in ethanol–water(E–W) than in isopropanol–water(I–W). The amorphous form of 5′-GMPNa_2 is more soluble than the crystalline form at the same mole fraction and temperature. Meanwhile, the crystalline forms and morphologies of the residual solids were characterized by PXRD and SEM. The results indicate that solid forms of 5′-GMPNa_2 transformed spontaneously from amorphous to crystalline when the ethanol proportion is ≥20%. In addition, increasing the pH facilitates the dissolution of 5′-GMPNa_2 and helps to maintain the crystalline form. The associated Gibbs free energy values were calculated to verify the trend of transformation from amorphous to crystalline 5′-GMPNa_2. These results should help to guide the industrial crystallization process and to obtain the crystalline form of 5′-GMPNa_2.

Changes in P2Y purinoreceptor-mediated intracellular calcium signal pathways results in inositol-1, 4, 5-triphosphate-sensitive calcium stores in rat small trigeminal ganglion neurons

BACKGROUND： Most of the currently available information on purinergic receptors （P2Rs） involved in pain transmission is based on results obtained in dorsal root ganglion or the spinal cord. However, the mechanism of P2Rs in trigeminal neuralgia remains unclear. OBJECTIVE： To investigate changes in the P2R-mediated calcium signaling pathway in nociceptive trigemJnal ganglion neurons. DESIGN, TIME AND SETTING： In vitro experiments were conducted at the Patch-Clamp Laboratory of Comprehensive Experiment Center of Anhui Medical University, China from September 2008 to June 2009. MATERIALS： Thapsigargin, caffeine, suramin, and adenosine 5＇-triphosphate were purchased from Sigma, USA. METHODS： Using Fura-2-based microfluorimetry, intracellular calcium concentration （[Ca^2＋]i） was measured in freshly isolated adult rat small trigeminal ganglion neurons before and after drug application. MAIN OUTCOME MEASURES： Fluorescent intensities were expressed as the ratio F340/F380 to observe [Ca^2＋]i changes. RESULTS： In normal extracellular solution and Ca^2＋-free solution, application of thapsigargin （1 μmol/L）, a sarcoplasmic reticulum Ca^2＋ pump adenosine 5＇-triphosphate inhibitor, as well as caffeine （20 mmol/L）, a ryanodine receptor agonist, triggered [Ca^2＋]i increase in small trigeminal ganglion neurons. A similar response was induced by application of adenosine 5＇-triphosphate （100 μmol/L）. In Ca^2＋-free conditions, adenosine 5＇-triphosphate-induced [Ca^2＋]i transients in small trigeminal ganglion neurons were inhibited in cells pre-treated with thapsigargin （P 〈 0.01）, but not by caffeine （P 〉 0.05）. In normal, extracellular solution, adenosine 5＇-triphosphate-induced [Ca^2＋]i transients in small trigeminal ganglion neurons were partly inhibited in cells pre-treated with thapsigargin （P 〈 0.05）. CONCLUSION： Inositol-1,4, 5-triphosphate （IP3）- and ryanodine-sensitive Ca^2＋ stores exist in rat nociceptive trigeminal ganglion neurons. Two pathways are involved in the purinoreceptor-mediated [Ca^2＋]i rise observed in nociceptive trigeminal ganglion neurons. One pathway involves the metabotropic P2Y receptors, which are associated with the IP3 sensitive Ca^2＋store, and the second pathway is coupled to ionotropic P2X receptors that induce the Ca^2＋ influx.

Study on disulfur-backboned nucleic acids:Part Ⅳ.Efficient synthesis of 3',5'-dithio-2'-deoxyguanosine

An efficient and novel method for synthesizing 3′,5′-dithio-2′-deoxyguanosine was described.In this method normal guanosine was used as the starting material.A very efficient procedure was used to synthesize 2-O-tosylguanosine 1,which used 0.1 eq.DBTO instead of 2 eq.1 was treated with LTBH to give 9-(2-deoxy-β-D-threo-pentofuranosyl)guanine 2.2 could be easily turned to the target compound.

Chemical synthesis, spectroscopic properties and biochemical evaluation of an adenine nucleotide derivative 2-aminoadenosine 5＇-triphosphate

An adenine nucleotide derivative 2-aminoadenosine 5＇-triphosphate was chemically synthesized through four steps and was characterized with 1H NMR, 31p NMR, 13C NMR, EA and FT-IR. Its ultraviolet and fluorescence properties at various pH values were studied. Two pKa values for the compound were determined by the curves of UV absorption dependency on pH, Which were 0.68 and 4.83, respectively. The values were consistent with those calculated from ACD/Labs software. In addition, hydrolysis of the adenine nucleotide derivative in the catalysis of potato apyrase was studied. The competition of the ATP analogue with ATP for potato apyrase＇ active site was proved to be a sequential reaction mechanism.

Existence of Heme Oxygenase-carbon Monoxide-cyclic Guanosine Monophosphate Pathway in Human Trabecular Meshwork Cells In Vitro

To confirm the existence of heme oxygenase (HO)-carbon monoxide (CO)- cyclic guanosine monophosphate (cGMP) pathway in the cultured human trabecular meshwork cells (HTMCs) in vitro, and to evaluate the inductive role of hemin on this pathway, HTMCs of the third to fourth generation were cultured in vitro. Reverse transcripase-polymerase chain reaction (RT-PCR) was employed for detection of HO-1 and HO-2 mRNA. Immunohistochemical staining was used to detect HO-1 and HO-2 proteins. Hemin was added into the culture solution. The HO-1 mRNA levels were quantified by RT-PCR. The relative amount of carbon monoxide released into the media was measured with the quantifying carbon monoxide hemoglobin (HbCO) by spectrophotometry. Radioimmunoassay was used to determine changes of cGMP in HTMCs. The results showed that cultured cells had the specific characteristics of HTMCs. Both HO-1 and HO-2 genes were expressed in HTMCs, as well as HO-1 and HO-2 proteins in HTMCs. Hemin induced HO-1 mRNA, HbCO and cGMP in a dose-dependent manner. In conclusion, HO-CO-cGMP pathway exists in the cultured HTMCs and can be induced by hemin. Pharmacological stimulation of HO-CO-cGMP pathway may constitute a novel therapeutic approach to rescuing glaucoma.

基于恒电位法快速测定肉汤中5'-鸟苷酸

目的 建立一种基于电化学参数分析的恒电位仪系统用于快速准确低成本地检测5’-鸟苷酸。方法 以Ru(bpy)22+/SMWCNTs/Au复合材料修饰的玻碳电极为媒介,筛选出与电子发生还原反应的靛蓝作为显色剂,研究了溶液pH和靛蓝添加量体积比对靛蓝电化学还原性能的影响,经过条件优化后构建一种使靛蓝脱色生成隐色体靛白的双电极体系恒电位装置。结果 在最佳检测条件下,当5’-鸟苷酸线性范围在0~0.6 mmol/L时,靛蓝脱色率随5’-鸟苷酸浓度的增大而呈线性上升(r^(2)=0.9614),该方法在肉汤样品中5’-鸟苷酸的检测过程中,显示出与电化学传感器技术高度相似的结果。结论 本方法能够有效地在实际应用过程中现场检测鲜味核苷酸,因其操作简便、便携微型化,在未来的食品质量检测领域将具有较大的市场优势与应用价值。

离子色谱法测定增味剂中的5′-肌苷酸二钠和5′-鸟苷酸二钠

建立了增味剂中5′-肌苷酸二钠和5′-鸟苷酸二钠的离子色谱分析方法。采用lonPacASll阴离子交换色谱柱，以20mmol／LNa2CO3一体积分数为15％的甲醇溶液为淋洗液，检测波长254um。方法已用于实际样品的测定。

高效毛细管电泳法测定酱油中5′-单磷酸核苷酸

建立高效毛细管电泳同时分离测定酱油中两种核苷酸鸟嘌呤-5′-单磷酸(GMP)和次黄嘌呤-5′-单磷酸(IMP)的方法。电泳条件:以50μm×60.2cm(有效长度50cm)未涂敷石英毛细管为分离柱,30mmol/L硼砂+30mmol/L碳酸钠+60mmol/L羟丙基-β-环糊精为分离缓冲溶液,50mmol/L醋酸溶液为样品介质,检测波长为254nm。GMP及IMP的校正峰面积与质量浓度在5～100mg/L范围内具有良好线性关系,线性相关系数分别为0.9998和0.9997,检出限均为2mg/L,定量限均为5mg/L。用该法测定了9种酱油,并与文献报道的高效液相色谱法的结果进行比较,结果满意。

酶法合成抗癌新药氟铁龙前体——5-FUR

筛选得到一株核苷磷酸化酶活力高的乙酰短杆菌 ,以该菌体为酶源酶法合成抗癌新药氟铁龙前体 5-氟尿苷 ,所用反应物为鸟苷和 5-氟尿嘧啶。在 1 50 m L的摇瓶装液 1 5m L的条件下进行研究 ,结果显示 :菌体添加量 2 0～ 30 g/L,底物浓度 1 0 0 mmol/L,磷酸盐浓度 50 mmol/L( p H8.0 ) ,60°C,摇床转速 1 60 r/min,反应 4h,5-氟尿苷的转化率可以达到 60

硫酸铈对5′-腺嘌呤及5′-鸟嘌呤核苷酸的水解断裂的催化作用

本文用核磁共振 (NMR)波谱和化学定磷法研究了 Ce(SO4) 2 对 5′-腺嘌呤核苷酸 (5′- AMP)及5′-鸟嘌呤核苷酸 (5′- GMP)的水解断裂作用。结果表明 :Ce(SO4) 2 在 37℃ ,酸性条件下使 5′- AMP断裂为腺嘌呤核苷 (A)及无机磷 ,使 5′- GMP断裂为鸟嘌呤核苷 (G)及无机磷 ,SO2 -4 浓度及酸强度对 5′- AMP及 5′- GMP的水解断裂程度有很大影响 ,并对其水解断裂机制进行了研究。

双波长比值光谱法测定5'-鸟苷酸钠、5'-肌苷酸钠、5'-尿苷酸钠含量

依据5'-鸟苷酸钠、5'-肌苷酸钠和5'-尿苷酸钠三组分的比值光谱特征,以尿苷酸钠为干扰组分时,选择258、285、244、280nm作为测定鸟苷酸钠和肌苷酸钠的波长;以肌苷酸钠为干扰组分时,选择211、241nm作为测定尿苷酸钠的波长。结果显示鸟苷酸钠在0.15～5mg/100ml,肌苷酸钠在0.2～6mg/100ml,尿苷酸钠在0.25～4mg/100ml范围具有良好的线性关系,平均回收率分别为100.2%、100.2%和99.5%。本法具有测定波长少、计算简单、光谱"分离"能力强以及能在低档分光光度计上实现、易于推广等特点。

外源5′-腺苷酸二钠和5′-鸟苷酸二钠对断奶仔猪生长性能及抗氧化能力的影响

将90头28日龄断奶的"杜×长×大"三元杂交仔猪随机分成3组,每组3个重复,对照组饲喂基础日粮,试验Ⅰ和Ⅱ组饲喂在基础日粮中分别添加0.03%5′-腺苷酸二钠和5′-鸟苷酸二钠的日粮,试验期28 d,测定仔猪生长性能和试验开始后第7、14和28天血清中的超氧化物歧化酶(SOD)活性、过氧化氢酶(CAT)活性、总抗氧化能力(T-AOC)和丙二醛(MDA)含量,研究外源5′-腺苷酸二钠和5′-鸟苷酸二钠对断奶仔猪生长性能和抗氧化功能的影响.结果表明,Ⅰ和Ⅱ组仔猪断奶后不同时间血清中的SOD活性呈下降趋势(P>0.05),其中,Ⅰ组仔猪第14天SOD活性显著低于对照组(P<0.05),对其他抗氧化指标没有显著影响(P>0.05),各组仔猪生长性能差异不显著(P>0.05).可见,日粮中分别添加5′-腺苷酸二钠和5′-鸟苷酸二钠对仔猪生长性能均无显著影响,5′-腺苷酸二钠有降低仔猪血清中SOD活性的作用.

磷酸二酯酶5基因多态性与阴茎勃起功能障碍的相关性研究

目的研究磷酸二酯酶5(PDE5)基因多态性与阴茎勃起功能障碍(ED)的相关性及其作用机制。方法选取2015年1月~2020年12月我院ED病人107例和健康体检男性102例分别为观察组和对照组,采集两组基本资料,检测PDE5基因多态性以及血清一氧化氮(NO)和环磷酸鸟苷(cGMP)水平并进行比较,分析各指标与勃起功能国际指数5(IIEF-5)评分的关系。结果ED型rs3806808位点T等位基因和TT基因型占比均低于对照组,差异有统计学意义(P<0.05);不同PDE5 rs3806808基因型病人ED严重程度差异显著(P<0.05),TG型和GG型重度病人占比低于TT型,轻、中度病人占比高于TT型,两者相比较差异有统计学意义(P<0.05);不同PDE5 rs3806808基因型病人血清NO水平比较无明显差异(P>0.05),TG型和GG型血清cGMP水平低于TT组,IIEF-5评分高于TT组,且GG型血清cGMP水平低于TG型,IIEF-5评分高于TG型,差异有统计学意义(P<0.05);多元线性回归分析结果显示,血清NO和PDE5 rs3806808基因型为ED病人IIEF-5评分重要影响因素(P<0.05)。结论PDE5 rs3806808基因多态性与ED发病和进展存在密切联系,其作用机制可能主要为影响cGMP表达,与NO表达无明显关系。

5′-鸟苷酸与茜素红S的反应及其在分析化学中的作用

采用UVVis光谱法研究了茜素红S(ARS)与5′鸟苷酸(5′GMP)在pH4.80的弱酸性缓冲溶液中生成络合物的结合反应。与试剂比较,络合物的最大吸收峰红移92nm,测得络合物和表观摩尔吸光系数为ε=1.3×104L·mol-1·cm-1;最大结合数n=10;浓度线性范围0.2～16mg/L;检出限为6.1×10-8mol/L。研究了ARS与5′GMP是分子间作用力的结合反应,并对时间、温度、离子强度对结合反应的影响,以及无机物、生物物质对反应体系的干扰情况进行了初步研究。

PDE5抑制剂与cGMP信号通路相关疾病的研究进展

磷酸二酯酶5(phosphodiesterase 5,PDE5)抑制剂通过阻断环磷酸鸟苷(cyclic guanosine monophosphate,cGMP)的分解,使包括一氧化氮(nitric oxide,NO)在内的血管舒张介质作用延长,从而导致阴茎和肺的血管舒张。PDE5主要在阴茎海绵体和肺血管中发现,所以其抑制剂的主要作用是延长阴茎勃起和降低肺血管压力。

鸟嘌呤核苷-3′,5′-环磷酸衍生物的合成及生物活性研究

本文报道用三价磷试剂与保护的鸟嘌呤核苷反应,经碘氧化生成鸟嘌呤核苷-3′,5′-环磷酸酯和磷酰胺,并对它们的生物活性做了初步研究,N^2-二甲胺基甲烯基-2′-叔丁基二甲基硅基鸟嘌呤核苷-3′,5′-环磷酸酯和磷酰胺对小鼠肝癌腹水细胞的DNA和RNA合成有一定的抑制作用。N^2-二甲胺基甲烯基鸟嘌呤核苷-3′,5′’-环磷酸丁酯的两个磷原子构型不同的异构体可激活腺苷酸环化酶,使大鼠成骨肉瘸细胞株ROS 17/2.8的cAMP水平增高。