Phase transformation and electrochemical charge storage properties of vanadium oxide/carbon composite electrodes synthesized via integration with dopamine

Chemically preintercalated dopamine (DOPA) molecules were used as both a reducing agent and a carbon precursor to prepare δ-V₂O₅·nH₂O/C, H₂V₃O₈/C, VO₂(B)/C, and V₂O₃/C nanocomposites via hydrothermal treatment or hydrothermal treatment followed by annealing under Ar flow. We found that the phase composition and morphology of the produced composites are influenced by the DOPA:V₂O₅ ratio used to synthesize (DOPA)_xV₂O₅ precursors through DOPA diffusion into the interlayer region of the δ-V₂O₅·nH₂O framework. The increase of DOPA concentration in the reaction mixture led to a more pronounced reduction of vanadium and a higher fraction of carbon in the composites’ structure, as evidenced by X-ray photoelectron spectroscopy and Raman spectroscopy measurements. The electrochemical charge storage properties of the synthesized nanocomposites were evaluated in Li-ion cells with nonaqueous electrolytes. δ-V₂O₅·nH₂O/C, H₂V₃O₈/C, VO₂(B)/C, and V₂O₃/C electrodes delivered high initial capacities of 214, 252, 279, and 637 mAh g^–1, respectively. The insights provided by this investigation open up the possibility of creating new nanocomposite oxide/carbon electrodes for a variety of applications, such as energy storage, sensing, and electrochromic devices.     

Characterization of the role of medial prefrontal cortex dopamine receptors in cocaine-induced locomotor activity.

Medial prefrontal cortex (mPFC) dopamine (DA) modulates the motor-stimulant response to cocaine. The present study examined the specific mPFC DA receptor subtypes that mediate this behavioral response. Intra-mPFC injection of the DA D?-like receptor agonist quinpirole blocked cocaine-induced motor activity, an effect that was prevented by coadministration of the D2 receptor antagonist sulpiride. Intra-mPFC injection of the selective D? receptor agonist PD 168,077 or the selective D? receptor agonist SKF 81297 did not alter the motor-stimulant response to cocaine. Finally, it was found that an intermediate dose of quinpirole, which only attenuated cocaine-induced motor activity, was not altered by SKF 81297 coadministration, suggesting a lack of synergy between mPFC D?, and D? receptors. These results suggest that D? receptor mechanisms in the mPFC are at least partly responsible for mediating the acute motor-stimulant effects of cocaine. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

菲酐-纳米金修饰电极同时检测抗坏血酸、多巴胺和尿酸的研究

多孔结构的3,4,9,10-茈四甲酸二酐（PTCDA）作为骨架,用抗坏血酸做还原剂制备纳米金（GNPs）,制备了高催化活性的PrC—GNPs复合纳米材料。将该材料用于玻碳电极的修饰（GCE）,制得PTC—GNPs复合材料修饰的电极（PTC—GNPs／GCE）。该修饰电极能够同时对尿酸（UA）、多巴胺（DA）和抗坏血酸（AA）进行检测。分别使用循环伏安法（CV）和差分脉冲伏安法（DPV）对UA、DA和AA和在修饰电极上的电化学行为进行研究。实验结果表明,在pH=5．0的PBS缓冲体系中,该修饰电极对UA、DA和AA的线性响应范围分别为0．002～0．462mol／L、0．002～0．352mol／L和0．04～1．54mol／L。该传感在临床医学检测领域具有一定的应用前景。     

Interaction between the DRD4 VNTR polymorphism and proximal and distal environments in alcohol dependence during emerging and young adulthood.

The manifestation of alcohol dependence at different developmental stages may be associated with different genetic and environmental factors. Taking a developmental approach, we characterized interaction between the dopamine receptor 4 variable number tandem repeat (DRD4 VNTR) polymorphism and developmentally specific environmental factors (childhood adversity, college/Greek organization involvement, and delayed adult role transition) on alcohol dependence during emerging and young adulthood. Prospective data were obtained from a cohort of 234 White individuals (56% women, 44% men) who were followed up at ages 18 through 34. A longitudinal hierarchical factor model was estimated to model a traitlike persistent alcohol dependence factor throughout emerging and young adulthood and 2 residual statelike alcohol dependence factors limited to emerging adulthood and young adulthood, respectively. We accounted for those alcohol dependence factors by modeling 3 two-way interaction effects between the DRD4 VNTR polymorphism and the 3 developmentally specific environment factors. Carriers of the DRD4 long allele showed greater susceptibility to environmental effects; they showed more persistent symptoms of alcohol dependence as childhood adversity increased and more alcohol dependence symptoms limited to emerging adulthood as college/Greek organization involvement increased. Alcohol dependence among noncarriers of the long allele, however, did not differ as a function of those environments. Although replication is necessary, these findings highlight the importance of repeated phenotypic assessments across development and modeling both distal and proximal environments and their interaction with genetic susceptibility at specific developmental stages. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Aripiprazole: A novel antipsychotic with dopamine stabilizing properties.

Notes that research in the field of psychopharmacology continues to focus on the development of antipsychotic agents that represent significant improvements over currently available agents in terms of side-effect profiles and efficacy. Several different lines of research have emerged, some of which capitalize on advances already attained with atypical or second-generation antipsychotics (SGAs), while others work towards identifying novel pharmacological targets around which to develop new agents. Although activity at serotonin receptors was a focus in the development of SGAs, dopamine remains the primary neurotransmitter of interest. One strategy has been to develop compounds that interact with dopamine receptors in ways that are different from those demonstrated by currently available agents. This approach has met with some experimental and clinical success, and has produced at least one agent--aripiprazole--which was recently approved for use in the US. Biochemical analysis has indicated that, as a potent partial D? agonist, aripiprazole works as an agonist at the presynaptic D? autoreceptors and as an antagonist at the postsynaptic D? receptors. It also exerts antagonist effects--like those of the atypical agents--at the 5-HT2A receptor. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Nicotine as a conditioned stimulus: Impact of attention-deficit/hyperactivity disorder medications.

People diagnosed with attention-deficit/hyperactivity disorder (ADHD) are at an increased risk to start smoking and have greater difficulty quitting. Nicotine, one of the principal addictive components of tobacco smoke, functioned as a conditioned stimulus (CS) for intermittent sucrose delivery in a Pavlovian drug discrimination task with rats. This study compared the ability of commonly prescribed ADHD medications (i.e., methylphenidate, atomoxetine, and bupropion) and additional dopamine reuptake inhibitors (i.e., cocaine and GBR 12909) to substitute for the CS effects of nicotine. Atomoxetine was also used to antagonize these CS effects. Rats acquired the discrimination as evidenced by increased dipper entries in nicotine (0.2 mg base/kg) sessions as compared with saline sessions. Nicotine generalization was dose dependent. Bupropion (10 and 20 mg/kg), methylphenidate (10 mg/kg), and cocaine (5 and 10 mg/kg) partially substituted for the 0.2 mg/kg nicotine CS. Atomoxetine did not substitute for the nicotine CS; however, atomoxetine (1 to 10 mg/kg) partially blocked nicotine's CS effects. These results suggest that atomoxetine, bupropion, and/or methylphenidate may be effective treatments for people diagnosed with ADHD and addicted to nicotine. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cytoprotective effects of anthocyanins and other phenolic fractions of Boysenberry and blackcurrant on dopamine and amyloid β‐induced oxidative stress in transfected COS‐7 cells

There is growing interest both from consumers and researchers in the role that berries play in human health. In the experiments reported here, we assessed the ability of anthocyanins and phenolic fractions of Boysenberry and blackcurrant to ameliorate the deleterious effect of the amyloid β_25–35 (100 µmol L^?1, 24 h) and dopamine (1 mmol L^?1, 4 h) on calcium buffering (recovery) of M1 muscarinic receptor‐transfected COS‐7 cells. Cell viability was also studied. Our results demonstrate that extracts of Boysenberry and blackcurrant showed significant protective effect and restored the calcium buffering ability of cells that had been subjected to oxidative stress induced by dopamine and the amyloid β_25–35. Blackcurrant polyphenolics showed slightly higher protective effect against dopamine, whereas Boysenberry polyphenolics had a higher effect against the amyloid β_25–35. In viability studies, all extracts showed significant protective effects against dopamine and amyloid β_25–35‐induced cytotoxicity. Our results provide further evidence for the protective effects of berries against the neurotoxic effect of dopamine and amyloid β_25–35 in brain cells. Copyright © 2007 Society of Chemical Industry     

Psychostimulant users are sensitive to the stimulant properties of alcohol as indexed by alcohol-induced cardiac reactivity.

One indicator of increased sensitivity to alcohol-induced reward is a heightened heart rate (HR) increase following alcohol intoxication, a characteristic associated with increased alcohol-induced dopamine (DA) release. The goal of this study was to determine whether users of drugs known to induce DA release have higher HR increases after alcohol intoxication than never users have. Sixty-four men with known drug-use histories participated in an alcohol challenge in which HR was measured. Stimulant users had significantly higher ethanol-induced HR increases than never users had, although use of marijuana or hallucinogens was not associated with this marker. Stimulant users obtained superior Sensitivity to Reward scores (R. Torrubia, C. ávila, J. Moltó, & X. Caseras, 2001) compared with never users. Stimulant drug users may be more sensitive to the stimulating properties of alcohol, and this appears to be mediated by superior activity in the Behavioral Approach System (J. A. Gray, 1991). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neural Substrates of Coping Behavior in the Rat: Possible Importance of Mesocorticolimbic Dopamine System.

This study measured expression of Fos protein, an indicator of neural activation, in 116 brain regions of rats that were able to control a stressor (i.e., avoid and/or escape an electric shock), and compared the changes with those observed in yoked rats that received the same shocks but without having control over them. The authors' interest was to find brain regions where elevated activity occurs in conjunction with control. Activity in these brain regions might be responsible for the consequences of having control, such as reduction of stress responses. Eleven brain regions were found in which rats with control showed significantly more Fos expression than was seen in yoked rats that did not have control. Six of these brain regions were part of the mesocorticolimbic dopamine system. These results point to the mesocorticolimbic dopamine system as being importantly involved in the mediation and/or the consequences of coping behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)