Influences of neuronal uptake and D2 autoreceptors on regulation of extracellular dopamine in the core, shell and rostral pole of the rat nucleus accumbens

Fast cyclic voltammetry in rat brain slices containing the nucleus accumbens, was used to examine the regulation of the extracellular concentration of electrically stimulated dopamine overflow in the core, shell and rostral pole. One μM (−)-sulpiride, significantly increased dopamine overflow in all 3 regions but only when the duration of stimulation was greater than 500 ms. One μM cocaine, significantly potentiated dopamine overflow in all 3 regions following all patterns of stimulation. In the presence of 1 μM cocaine, superfusion with 1 μM (−)-sulpiride did not result in a further increase in dopamine overflow at any frequency of stimulation in the rostral pole, but significant increases in dopamine overflow were observed after stimulation with 20 pulses at 10 or 20 Hz in the core or shell; the degree of potentiation was greater in the shell than core. Quinpirole inhibited single pulse stimulated dopamine overflow in a concentration dependent manner (maximum inhibition (100%) in all regions) but was significantly less potent in the rostral pole than in the core or shell. Increasing the number of pulses to 2 or 4 pulses at 50 Hz resulted in a shift of the quinpirole dose-response curve to the right in all regions and in the rostral pole, a significant reduction in the maximum inhibition of dopamine overflow to both stimulation parameters. In the shell a significant reduction in maximum inhibition was only seen with 4 pulses at 50 Hz stimulation, whereas in the core there was no change in the maximum inhibitory effect of quinpirole. Neuronal uptake and D₂ autoreceptor activity contribute to regulation of the extracellular concentration of dopamine in core, shell and rostral pole. The relative importance of either uptake or autoreceptor control is region and stimulus dependent.     

Dynamics of 5-hydroxytryptamine released from dopamine neurons in the caudate putamen of the rat

Fast-scan cyclic voltammetry has been used for the detection of 5-hydroxytryptamine (5-HT) in vivo. The applied potential waveform was previously optimized to maximize response times to concentration changes. This technique has been used to reinvestigate 5-HT release from striatal dopaminergic terminals after pharmacological pretreatment as reported by Stamford et al. [13]. Our results concur with those set forth by Stamford and further show that the dopamine transporter is responsible for 5-HT uptake in this experiment.     

Nafion修饰玻碳电极测定微量左旋咪唑的研究

以玻碳电极为基体,制备了nafion修饰电极,研究了非电活性阳离子药物左旋咪唑在该电极上的测定方法及作用机理。将左旋咪唑加到含电活性阳离子药物多巴胺的电解质溶液中,使多巴胺峰电流下降,峰电流的降低与左旋咪唑的浓度对数在2×10^-6～8×10^-5mol·r^-1范围内呈良好线性关系,本方法的检测下限为1×10^-6mol·L⁶,回收范围为96.8%～105.8%,相对标准偏差为3.2%(n=10)。     

半微分阳极溶出伏安法应用于水样和发样中铜、铅、镉、锌的测定

研究用半微分阳极溶出伏安法同时测定水样和儿童发样中的铜、铅、镉、锌,选择了最佳测定条件,在乙二胺-三乙醇胺溶液中,作出很好的极谱图。峰电流与铜、铅、镉,锌浓度在5～75μg/L范围内呈线性关系,回收率在98％～106％。方法迅速、简便、灵敏、准确。     

酸性污水汽提塔的模拟算法

开发了酸性污水汽提塔的模拟算法。首先，在比较各种相平衡模型基础上，选择ＳＷＥＱ汽液相平衡模型，并成功地开发了稳定性好的露点温度算法。其次，针对酸性污水汽提塔的特点，选择汽相摩尔分率为迭代变量，应用新松驰法实现了汽提塔的模拟计算。经３个工业汽提塔实例考核，证明本算法所需内存小，计算速度快，收敛稳定性好。计算结果与实测值或设计值基本相符。     

常压湿法微波消化人发用于溶出伏安分析

文章介绍了用于溶出伏安分析的常压湿法微波消化人发的方法,可同时测定人发中的锌和铜.常压湿法微波消化技术比高压微波消化法更安全,比目前常用的消解方法更简便快速.实验的回收率和精密度表明,本法消解生物作品适合于用阳极溶出伏安法进行元素分析.     

Multiple amphetamine injections reduce the release of ascorbic acid in the neostriatum of the rat

Voltammetric signals were recorded bilaterally with unmodified or electrochemically-modified carbon-fiber electrodes in the neostriatum of rats that sustained a unilateral depletion of dopamine by pretreatment with 6-hydroxydopamine. In both hemispheres, single daily injections of D-amphetamine (5.0 mg/kg or steadily increasing doses beginning with 6.0 mg/kg) for 6 consecutive days significantly reduced the rise in oxidation current produced by a challenge injection of 2.5 mg/kg D-amphetamine compared to the response obtained from saline-treated controls. Voltammetric scans indicated that the oxidized substance shared the electrochemical characteristics of ascorbic acid. It appears, therefore, that multiple amphetamine injections reduce the release of ascorbic acid in the neostriatum and that this effect does not depend on the integrity of dopaminergic neurons.     

甲氧苄氨嘧啶(TMP)的电分析化学研究及其在药物分析中的应用

本文用微分脉冲极谱法和循环伏安法研究了甲氧苄氨嘧啶(TMP)的电化学行为,选择了最佳的测定条件,TMP的检出限可达2.0×10^-7mol/L,方法灵敏度较高,并研制了TMP-PVC膜离子选择性电极,试验了该电极的各种特性及Nernst响应范围。本法应用于制剂中TMP的测定,选择性好,干扰少,毋须分离,方法简便快速。选择电极在人尿和血清的介质中测定,也能获得良好的结果。     

The Surgical Treatments for the Long Saphenous Varicose Vein

Objective To summarize the experiences of the surgical treatments for the long saphenous varicose vein. Methods 545 cases （667 legs） were treated with smaller incisions and stripping of the long saphenous vein. Results 500 cases （91.7%） were followed-up on an average of 3.7 years. The result shows that this technique could decrease the operative injures and the complications. The recurrent rate is very low （1.2%）. Conclusion This easy and reasonable operative technique is worth recommending due to their ideal effects.     

Spectroelectrochemical study of the oxidation of aminophenols on platinum electrode in acid medium

The electrochemical oxidation of para-, meta- and ortho-aminophenols was carried out using a platinum electrode in aqueous acid medium. The spectroscopic results indicate that p-aminophenol suffers hydrolysis giving the formation of hydroquinone/p-benzoquinone. CO₂ has been detected by in situ FTIR spectroscopy as the main soluble oxidation product. The m-aminophenol oxidation produces a blocking polymeric film on the platinum surface. The main oxidation products detected by in situ infrared spectroscopy were CO₂ and quinone. Cyclic voltammetry and in situ FTIR spectroscopy were combined to study the redox processes of the conducting polymer obtained in the o-aminophenol oxidation. The spectroscopic results indicate that phenoxazine units are produced during the oxidation/reduction of poly(o-aminophenol).