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Fast scan cyclic voltammetry

Michael P Saddoris
Repeated self-administration of cocaine is associated with impairments in motivated behaviors as well as alterations in both dopamine (DA) release and neural signaling within the nucleus accumbens (NAc). These impairments are present even after several weeks of abstinence from drug taking, suggesting that the self-administration experience induces long-lasting neuroplastic alterations in the mesolimbic DA circuit. To understand these changes at the terminal level, rats were allowed to self-administer either cocaine intravenously (∼1 mg/kg per infusion) or water to a receptacle (control) in 2-h sessions over 14 days, followed by 30 days of enforced abstinence...
September 2016: ENeuro
Martin J Bobak, Matthew W Weber, Melissa A Doellman, Douglas R Schuweiler, Jeana M Athens, Steven A Juliano, Paul A Garris
Modafinil (MOD) exhibits therapeutic efficacy for treating sleep and psychiatric disorders, but its mechanism is incompletely understood. Compared to other psychostimulants inhibiting dopamine (DA) uptake, MOD weakly interacts with the dopamine transporter (DAT) and modestly elevates striatal dialysate DA, suggesting additional targets besides DAT. However, the ability of MOD to induce wakefulness is abolished with DAT knockout, conversely suggesting that DAT is necessary for MOD action. Another psychostimulant target, but one not established for MOD, is activation of phasic DA signaling...
October 12, 2016: Journal of Pharmacology and Experimental Therapeutics
R Asri, B O'Neill, J C Patel, K A Siletti, M E Rice
The study of transmitter interactions in reward and motor pathways in the brain, including the striatum, requires methodology to detect stimulus-driven neurotransmitter release events. Such methods exist for dopamine, and have contributed to the understanding of local and behavioral factors that regulate dopamine release. However, factors that regulate release of another key transmitter in these pathways, acetylcholine (ACh), are unresolved, in part because of limited temporal and spatial resolution of current detection methods...
October 3, 2016: Analyst
En Ning Saw, Viktoria Grasmik, Christian Rurainsky, Matthias Epple, Kristina Tschulik
The increasing interest in producing bimetallic nanoparticles and utilizing them in modern technologies sets the demand for fast and affordable characterization of these materials. To date Scanning Transmission Electron Microscopy (STEM) coupled to energy dispersive X-ray spectroscopy is usually used to determine the size and composition of alloy nanoparticles, which is time-consuming and expensive. Here electrochemical single nanoparticle analysis is presented as an alternative approach to infer the particle size and composition of alloy nanoparticles, directly in a dispersion of these particles...
September 15, 2016: Faraday Discussions
P Gallay, E Tosi, R Madrid, M Tirado, D Comedi
We present a glucose biosensor based on ZnO nanowire self-sustained films grown on compacted graphite flakes by the vapor transport method. Nanowire/graphite films were fragmented in water, filtered to form a colloidal suspension, subsequently functionalized with glucose oxidase and finally transferred to a metal electrode (Pt). The obtained devices were evaluated using scanning electron microscopy, energy-dispersive x-ray spectroscopy, cyclic voltammetry and chronoamperometry. The electrochemical responses of the devices were determined in buffer solutions with successive glucose aggregates using a tripolar electrode system...
October 21, 2016: Nanotechnology
Megan E Fox, Elizabeth S Bucher, Justin A Johnson, R Mark Wightman
Central norepinephrine signaling influences a wide range of behavioral and physiological processes, and the ventral bed nucleus of the stria terminalis (vBNST) receives some of the densest norepinephrine innervation in the brain. Previous work describes norepinephrine neurons as projecting primarily unilaterally; however, recent evidence for cross-hemispheric catecholamine signaling challenges this idea. Here, we use fast-scan cyclic voltammetry and retrograde tracing to characterize cross-hemispheric norepinephrine signaling in the vBNST...
September 27, 2016: ACS Chemical Neuroscience
Giovanni Hernandez, Marie-Pierre Cossette, Peter Shizgal, Pierre-Paul Rompré
Glutamate stimulates ventral midbrain (VM) N-Methyl-D-Aspartate receptors (NMDAR) to initiate dopamine (DA) burst firing activity, a mode of discharge associated with enhanced DA release and reward. Blockade of VM NMDAR, however, enhances brain stimulation reward (BSR), the results can be explained by a reduction in the inhibitory drive on DA neurons that is also under the control of glutamate. In this study, we used fast-scan cyclic voltammetry (FSCV) in anesthetized animals to determine whether this enhancement is associated with a change in phasic DA release in the nucleus accumbens...
2016: Frontiers in Behavioral Neuroscience
Courtney M Cameron, R Mark Wightman, Regina M Carelli
Cocaine addiction is a chronic relapsing disorder that is difficult to treat in part because addicts relapse even after extended periods of abstinence. Given the importance of the mesolimbic dopamine (DA) system in drug addiction, we sought to characterize cocaine abstinence induced changes in rapid DA signaling in the nucleus accumbens (NAc). Here, rats were trained to self-administer cocaine for 14 consecutive days, then divided into two groups. Day 1 rats (D1; n = 7) underwent 24 h of abstinence; Day 30 rats (D30; n = 7) underwent one month of abstinence...
December 2016: Neuropharmacology
Kyle Wolf, Georgy Zarkua, Shyue-An Chan, Arun Sridhar, Corey Smith
Neuroendocrine chromaffin cells of the adrenal medulla in rat receive excitatory synaptic input through anterior and posterior divisions of the sympathetic splanchnic nerve. Upon synaptic stimulation, the adrenal medulla releases the catecholamines, epinephrine, and norepinephrine into the suprarenal vein for circulation throughout the body. Under sympathetic tone, catecholamine release is modest. However, upon activation of the sympathoadrenal stress reflex, and increased splanchnic firing, adrenal catecholamine output increases dramatically...
September 2016: Physiological Reports
Terry Lohrenz, Kenneth T Kishida, P Read Montague
Activity in midbrain dopamine neurons modulates the release of dopamine in terminal structures including the striatum, and controls reward-dependent valuation and choice. This fluctuating release of dopamine is thought to encode reward prediction error (RPE) signals and other value-related information crucial to decision-making, and such models have been used to track prediction error signals in the striatum as encoded by BOLD signals. However, until recently there have been no comparisons of BOLD responses and dopamine responses except for one clear correlation of these two signals in rodents...
October 5, 2016: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
Polina Kosillo, Yan-Feng Zhang, Sarah Threlfell, Stephanie J Cragg
Corticostriatal regulation of striatal dopamine (DA) transmission has long been postulated, but ionotropic glutamate receptors have not been localized directly to DA axons. Striatal cholinergic interneurons (ChIs) are emerging as major players in striatal function, and can govern DA transmission by activating nicotinic receptors (nAChRs) on DA axons. Cortical inputs to ChIs have historically been perceived as sparse, but recent evidence indicates that they strongly activate ChIs. We explored whether activation of M1/M2 corticostriatal inputs can consequently gate DA transmission, via ChIs...
August 27, 2016: Cerebral Cortex
Nathan T Rodeberg, Justin A Johnson, Elizabeth S Bucher, R Mark Wightman
The neurotransmitter dopamine is heavily implicated in intracranial self-stimulation (ICSS). Many drugs of abuse that affect ICSS behavior target the dopaminergic system, and optogenetic activation of dopamine neurons is sufficient to support self-stimulation. However, the patterns of phasic dopamine release during ICSS remain unclear. Early ICSS studies using fast-scan cyclic voltammetry (FSCV) rarely observed phasic dopamine release, which led to the surprising conclusion that it is dissociated from ICSS...
September 1, 2016: ACS Chemical Neuroscience
Elefterios Trikantzopoulos, Cheng Yang, Mallikarjunarao Ganesana, Ying Wang, B Jill Venton
Glass insulated carbon-fiber microelectrodes (CFMEs) are standard tools for the measurement of neurotransmitters. However, electrodes are fabricated individually and the glass can shatter, limiting application in higher order mammals. Here, we developed a novel microelectrode batch fabrication method using a 3D-printed mold and polyimide resin insulating agent. The 3D-printed mold is low cost, customizable to change the electrode shape, and allows 40 electrodes to be made simultaneously. The polyimide resin is biocompatible, quick to cure, and does not adhere to the plastic mold...
September 21, 2016: Analyst
Siti Nur Akmar Mohd Yazid, Illyas Md Isa, Norhayati Hashim
This paper presents the fabrication of a highly sensitive and selective glucose sensor based on cuprous oxide/graphene nanocomposites-modified glassy carbon electrode (Cu2O/graphene/GCE). The Cu2O/graphene nanocomposites were synthesized based on a simple and straightforward chemical reduction process in alkaline aqueous solution using sodium carbonate as reductant. The size and shape of Cu2O nanoparticles on graphene sheets can be controlled by changing the amount of graphene oxide added during reaction. The electrochemical properties of Cu2O/graphene/GCE in 0...
November 1, 2016: Materials Science & Engineering. C, Materials for Biological Applications
Pavithra Pathirathna, Thushani Siriwardhane, Stephen L Morgan, Shawn P McElmurry, Parastoo Hashemi
Metal speciation controls the behavior of aqueous metal ions. Fundamental thermodynamic parameters, such as the formation constant (Kf) of metal-ligand equilibria, provide useful speciation information. Although this information can be determined by spectroscopic techniques with high accuracy, it comes at the expense of time and cost. In this work, we studied Cu(2+) complexation with different ligands using an ultra-fast method, fast scan cyclic voltammetry (FSCV) at carbon-fiber microelectrodes (CFMs). We observed a correlation between the FSCV response and the previously reported Cu(2+)-ligand equilibrium constants...
October 17, 2016: Analyst
Adem Can, Douglas O Frost, Roger Cachope, Joseph F Cheer, Todd D Gould
Chronic lithium treatment effectively reduces behavioral phenotypes of mania in humans and rodents. The mechanisms by which lithium exerts these actions are poorly understood. Pre-clinical and clinical evidence have implicated increased mesolimbic dopamine (DA) neurotransmission with mania. We used fast-scan cyclic voltammetry to characterize changes in extracellular DA concentrations in the nucleus accumbens (NAc) core evoked by 20 and 60 Hz electrical stimulation of the ventral tegmental area (VTA) in C57BL6/J mice treated either acutely or chronically with lithium...
August 11, 2016: Journal of Neurochemistry
Kristen Ann Stout, Amy R Dunn, Kelly M Lohr, Shawn P Alter, Rachel A Cliburn, Thomas S Guillot, Gary W Miller
Drugs of abuse induce sensitization, which is defined as enhanced response to additional drug following a period of withdrawal. Sensitization occurs in both humans and animal models of drug reinforcement and contributes substantially to the addictive nature of drugs of abuse, as it is thought to represent enhanced motivational wanting for drug. The ventral pallidum, a key member of the reward pathway, contributes to behaviors associated with reward, such as sensitization. Dopamine inputs to the ventral pallidum have not been directly characterized...
August 8, 2016: ACS Chemical Neuroscience
Jamie H Rose, Anushree N Karkhanis, Björn Steiniger-Brach, Sara R Jones
The development of pharmacotherapeutics that reduce relapse to alcohol drinking in patients with alcohol dependence is of considerable research interest. Preclinical data support a role for nucleus accumbens (NAc) κ opioid receptors (KOR) in chronic intermittent ethanol (CIE) exposure-induced increases in ethanol intake. Nalmefene, a high-affinity KOR partial agonist, reduces drinking in at-risk patients and relapse drinking in rodents, potentially due to its effects on NAc KORs. However, the effects of nalmefene on accumbal dopamine transmission and KOR function are poorly understood...
2016: International Journal of Molecular Sciences
Adem Can, Panos Zanos, Ruin Moaddel, Hye Jin Kang, Katinia S S Dossou, Irving W Wainer, Joseph F Cheer, Douglas O Frost, Xi-Ping Huang, Todd D Gould
Following administration at subanesthetic doses, (R,S)-ketamine (ketamine) induces rapid and robust relief from symptoms of depression in treatment-refractory depressed patients. Previous studies suggest that ketamine's antidepressant properties involve enhancement of dopamine (DA) neurotransmission. Ketamine is rapidly metabolized to (2S,6S)- and (2R,6R)-hydroxynorketamine (HNK), which have antidepressant actions independent of N-methyl-d-aspartate glutamate receptor inhibition. These antidepressant actions of (2S,6S;2R,6R)-HNK, or other metabolites, as well as ketamine's side effects, including abuse potential, may be related to direct effects on components of the dopaminergic (DAergic) system...
October 2016: Journal of Pharmacology and Experimental Therapeutics
Megan E Fox, Nathan T Rodeberg, R Mark Wightman
Dysregulated catecholamine signaling has long been implicated in drug abuse. Although much is known about adaptations following chronic drug administration, little work has investigated how a single drug exposure paired with withdrawal influences catecholamine signaling in vivo. We used fast-scan cyclic voltammetry in freely moving rats to measure real-time catecholamine overflow during acute morphine exposure and naloxone-precipitated withdrawal in two regions associated with the addiction cycle: the dopamine-dense nucleus accumbens (NAc) and norepinephrine-rich ventral bed nucleus of the stria terminalis (vBNST)...
August 17, 2016: Neuropsychopharmacology: Official Publication of the American College of Neuropsychopharmacology
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