话说葡萄酒中的抗癌明星——白藜芦醇

白藜芦醇被喻为继紫杉醇之后的又一新的绿色抗癌药物,是备受关注的一种具有重要生理活性的天然物质。主要介绍了其结构、性质、存在、生理功能及生产方法等。     

荧光法测定SD大白鼠不同脑区的单胺类神经递质

以荧光光谱法定量地研究了不同浓度的司考林作用下,鼠脑组织中去甲肾上腺素、多巴胺和5-羟色胺的定量变化,从而表达了中枢神经递质的变化规律.     

Synaptic inhibition and γ-aminobutyric acid in the mammalian central nervous system

Signal transmission through synapses connecting two neurons is mediated by release of neurotransmitter from the presynaptic axon terminals and activation of its receptor at the postsynaptic neurons. γ-Aminobutyric acid (GABA), non-protein amino acid formed by decarboxylation of glutamic acid, is a principal neurotransmitter at inhibitory synapses of vertebrate and invertebrate nervous system. On one hand glutamic acid serves as a principal excitatory neurotransmitter. This article reviews GABA researches on; (1) synaptic inhibition by membrane hyperpolarization, (2) exclusive localization in inhibitory neurons, (3) release from inhibitory neurons, (4) excitatory action at developmental stage, (5) phenotype of GABA-deficient mouse produced by gene-targeting, (6) developmental adjustment of neural network and (7) neurological/psychiatric disorder. In the end, GABA functions in simple nervous system and plants, and non-amino acid neurotransmitters were supplemented.     

毛细管电泳-激光诱导荧光测定大鼠血浆内痕量氨基酸类神经递质

用菁色素衍生物 (Cy5 )作为荧光衍生试剂 ,毛细管电泳结合激光诱导荧光分离测定痕量氨基酸类神经递质甘氨酸和谷氨酸。讨论了Cy5浓度 ,缓冲液浓度 ,pH值和反应时间等实验条件对衍生和分离的影响。衍生物的荧光强度和氨基酸的浓度在 7.5× 1 0 - 8～ 3 .5× 1 0 - 6 mol L范围内呈现良好的线性 ,线性相关系数均达到 0 .999。甘氨酸和谷氨酸的最低检出限浓度分别为 3 .3× 1 0 - 9mol L和 1 .0×1 0 - 9mol L。测定了大鼠血浆中甘氨酸和谷氨酸的浓度 ,分别为 (62± 1 4 )× 1 0 - 6 mol L和 (1 9± 2 )× 1 0 - 6 mol L。与其它氨基标记荧光试剂 ,如FITC和TRITC相比 ,Cy5与一级胺反应时间短 ,选择性高     

Determination of dopamine and its relativity of baicalin in rat nuclei after intravenous administration of flavonoids from Scutellariae radix

Baicalin is an active component of Scutellariae radix extracts. It can cross the blood-brain barrier and distribute in cerebral nuclei. However, its mechanism and the effects on the nuclei where it accumulates remain unclear. We used an HPLC-electrochemical detection method to determine the dopamine in cerebral nuclei after intravenous administration of flavonoids from Scutellariae radix and analyzed the relativity between baicalin and DA in cerebral nuclei. We found that the dopamine system is another target system of brain function which baicalin acts on.     

利用基于~1H NMR的代谢组学分析研究重离子辐射对大鼠额叶皮质区的影响

太空辐射尤其是重离子辐射可造成DNA的破坏、细胞死亡、以及一些癌症的发生, 是人类深空探索进程中急需克服的难题. 本文通过重离子加速器产生 ~(12)C~(6+)重离子束对大鼠头部进行一定剂量的辐射, 模拟空间重离子辐射对中枢神经系统(CNS)的生物学效应. 采用基于 ~1H NMR的代谢组学方法对辐射大鼠大脑额叶皮质区进行了测定分析, 结合数据的统计分析和检验, 发现了包括一些重要CNS神经递质在内的代谢物含量发生明显变化. 这些代谢物主要为: 牛磺酸、乳酸、谷氨酸、 4-氨基丁酸、以及磷酸胆碱等. 结合差异蛋白质组结果分析, 包括4-氨基丁酸、谷氨酸、乳酸、牛磺酸等在内的代谢物参与的主要生物途径, 如神经递质的合成途径, 以及神经递质受体介导的信号途径可能受重离子辐射的负面影响. 这些发现将为进一步阐明重离子辐射效应的分子机制提供有利信息, 从而为从生物学途径探寻有效重离子辐射防护措施提供依据.     

Sensitive determination of norepinephrine,epinephrine, dopamine and 5‐hydroxytryptamine by coupling HPLC with [Ag(HIO6)2]5−–luminol chemiluminescence detection

Based on the enhancing effects of norepinephrine (NE), epinephrine (EP), dopamine (DA) and 5‐hydroxytryptamine (5‐HT) on the chemiluminescence (CL) reaction between [Ag(HIO₆)₂]^5? and luminol in alkaline solution, a high‐performance liquid chromatography (HPLC) method with CL detection was explored for the sensitive determination of monoamine neurotransmitters for the first time. The UV–visible absorption spectra were recorded to study the enhancement mechanism of monoamine neurotransmitters on the CL of [Ag(HIO₆)₂]^5? and luminol reaction. The HPLC separation of NE, EP, DA and 5‐HT was achieved with isocratic elution using a mixture of aqueous 0.2% phosphoric acid and methanol (5:95, v/v) within 11.0 min. Under the optimized conditions, the detection limits of NE, EP, DA, and 5‐HT were 4.8, 0.9, 1.9 and 2.3 ng/mL, respectively, corresponding to 17.6–96.0 pg for 20 μL sample injection. The recoveries of monoamine neurotransmitters in rat brain were >95.6% with the precisions expressed by RSD <5.0%. The validated HPLC‐CL method was successfully applied for the quantification of NE, EP, DA and 5‐HT in rat brain. This method has promising potential for some biological and clinical investigations focusing on the levels of monoamine neurotransmitters. Copyright © 2016 John Wiley & Sons, Ltd.     

Molecular model of the neural dopamine transporter

The dopamine transporter (DAT) regulates the action of dopamine by reuptake of the neurotransmitter into presynaptic neurons, and is the main molecular target of amphetamines and cocaine. DAT and the Na⁺/H⁺ antiporter (NhaA) are secondary transporter proteins that carry small molecules across a cell membrane against a concentration gradient, using ion gradients as energy source. A 3-dimensional projection map of the E. coli NhaA has confirmed a topology of 12 membrane spanning domains, and was previously used to construct a 3-dimensional NhaA model with 12 trans-membrane -helices (TMHs). The NhaA model, and site directed mutagenesis data on DAT, were used to construct a detailed 3-dimensional DAT model using interactive molecular graphics and empiric force field calculations. The model proposes a dopamine transport mechanism involving TMHs 1, 3, 4, 5, 7 and 11. Asp79, Tyr252 and Tyr274 were the primary cocaine binding residues. Binding of cocaine or its analogue, (–)-2-carbomethoxy-3-(4-fluorophenyl)tropane (CFT), seemed to lock the transporter in an inactive state, and thus inhibit dopamine transport. The present model may be used to design further experimental studies of the molecular structure and mechanisms of DAT and other secondary transporter proteins.     

A New Fluorometric Method for the Detection of the Neurotransmitter Acetylcholine in Water Using a Dansylcholine Complex with p-Sulfonated Calix[8]arene

A new method for the fluorometric detection of the neurotransmitter acetylcholine (ACh) in water is presented. Use of the fluorescence of dansylcholine (DANCh) bound to p-sulfonated calix[8]arene affords a new fluorometric method for the detection of ACh (>10^-4 M) inaqueous solution (pH = 6.9). The fluorescence intensity of DANCh in aqueous solution was enhanced 1.8 fold after the complexation with p-sulfonated calix[8]arene. The addition of ACh to the aqueous solution of the DANCh-calix[8]arene complex significantly decreased the fluorescence intensity, which results from the replacement of DANCh in the complex with ACh. The effects of other synaptic neurotransmitters on the fluorescence of the DANCh complex were examined for dopamine, histamine, ATP, GABA, glycine, l-glutamic acid, and l-aspartic acid. Among the neurotransmitters studied, ACh was most effective in changing the fluorescence of the DANCh complex. Possible application of the DANCh complex dye for the detection of ACh in biological systems is discussed.     

径向电场调制毛细管电泳法用于神经递质分离

利用双向电场控制毛细管电泳系统，考察了神经递质的分离。在pH2.5的0.01mol/L磷酸盐缓冲体系中，通过加入20％（V／V）正丙醇，改善了多巴胺和5－羟色胺的分离效果，但仍不太理想。通过施加径向电场，可进一步提高分离度。本研究不仅拓宽了径向电场调控的样品分离范围，而且为生物活性物质的痕量分析提供了参考依据。