Combined activation of dopamine D1- and NMDA-glutamate receptors in the nucleus accumbens has been strongly implicated in instrumental learning, the process in which an individual learns that a specific action has a wanted outcome. To assess dopaminergic activity, we presented rats with two sessions (30 trials each) of a one-lever appetitive instrumental ...

The effects of clonidine, an alpha2 adrenoceptor agonist, on extracellular concentrations of dopamine and gamma-aminobutyric acid (GABA) in the nucleus accumbens of rats were studied by using in vivo brain microdialysis. Clonidine (5 microg/kg i.v.) significantly decreased the brain microdialysate concentration of dopamine in the ...

Dopamine transmission within the nucleus accumbens has been implicated in associative reinforcement learning. We investigated the effect of appetitive classical conditioning on dopamine efflux in the rat nucleus accumbens shell and core, as dopamine may be differentially ...

The mu- and delta-opioid receptors located at the terminal level in nucleus accumbens are involved in the opiate modulation of dopamine release in this brain area. However, recent studies suggest that the effects of opioid drugs on the core subregion of nucleus accumbens may completely differ from those observed in the shell. We used ...

In order to explore potential therapeutic implications of cannabinoid antagonists, the effects of the prototypical cannabinoid antagonist SR141716A on monoamine efflux from the medial prefrontal cortex and the nucleus accumbens of the rat were investigated by in vivo microdialysis.SR141716A moderately increased serotonin efflux and ...

The ability of an organism to control a stressor can modulate many of the consequences of stress. Previous research indicates that uncontrollable stress (inescapable shock, IS) activates serotonergic (5-HT) neurons of the dorsal raphe nucleus (DRN) to a greater degree than controllable stress (escapable shock, ES), potentiating 5-HT efflux in the DRN and in target regions. ...

Selegiline is an irreversible inhibitor of monoamine oxidase B with trophic and neuroprotective effects. Because of evidence for decreased dopaminergic function during the withdrawal syndromes associated with opiates and other medications with potential for abuse, we investigated effects of treatment with selegiline on in vitro measures of dopamine efflux ...

Simultaneous dopamine and single-unit recordings reveal accumbens GABAergic responses: Implications including dopamine and GABA. For this reason, the neurotransmitters that are central to this behavior and cyclic voltammetry at the same electrode in awake rats to simultaneously examine cell firing and dopamine

Professor Trevor Robbins explains that the reward system, where dopamine mediates messages to the nucleus accumbens, is artificially activated by certain drugs.

Glutamate Transmission in the Nucleus Accumbens Mediates Relapse in Cocaine Addiction Jennifer L Carolina, Charleston, South Carolina 29425 Elevated dopamine transmission in the nucleus accumbens in the nucleus accumbens, is a primary mediator of cocaine- induced reinstatement of drug-seeking behavior

Corticosteroid receptor modulation of mesoaccumbens dopamine neurotransmission is believed to be a key neurobiological mechanism mediating the effects of stress in addiction. Importantly, nucleus accumbens (NAc) subregions (core and shell) are reported to respond differentially to fluctuating basal levels of glucocorticoids, with dopaminergic responses in ...

The Coolidge effect describes the reinitiation of sexual behavior in a "sexually satiated" animal in response to a novel receptive mate. Given the role of the mesolimbic dopamine (DA) system in the initiation and maintenance of motivated behavior, microdialysis was used to monitor nucleus accumbens (NAC) DA transmission during copulation, sexual satiety, ...

Tonic dopamine (DA) signaling is widely regarded as playing a central role in effort-based decision making and in the motivational control of instrumental performance. The current study used microdialysis to monitor changes in extracellular DA levels across subregions of the nucleus accumbens and dorsal striatum of rats as they lever pressed for food ...

Tonic dopamine (DA) signaling is widely regarded as playing a central role in effort-based decision-making and in the motivational control of instrumental performance. The current study used microdialysis to monitor changes in extracellular DA levels across subregions of the nucleus accumbens and dorsal striatum of rats as they lever pressed for food ...

Alpha-methyl-p-tyrosine (AMPT) is known to inhibit the formation of dopamine (DA) in the cytosol of dopaminergic neurons and is therefore used to study the role of the cytosolic DA pools. AMPT is usually administered systemically. In the present study, however, the effects of locally infused AMPT on the efflux of DA from the nucleus ...

In the present study, we examined whether exposing rats to a high-dose regimen of manganese chloride (Mn) during the postnatal period would depress presynaptic dopamine functioning and alter nonassociative and associative behaviors. To this end, rats were given oral supplements of Mn (750 ?g/day) on postnatal days (PD) 1�21. On PD 90, dopamine ...

Atypical antipsychotic drugs, which are more potent direct acting antagonists of brain serotonin (5-HT)(2A) than dopamine (DA) D(2) receptors, preferentially enhance DA and acetylcholine (ACh) efflux in the rat medial prefrontal cortex (mPFC) and hippocampus (HIP), compared with the nucleus accumbens (NAc). These effects may contribute ...

Professor Trevor Robbins explains that drug addiction involves chemical and neural processes with dopamine and the nucleus accumbens particularly important.

Doctor Abraham Zangen point out that dopamine and BDNF levels in the nucleus accumbens and hippocampus of depressed patients are different. Treatment with antidepressants or ECT can impact these differences.

Brief Communications Phasic Dopamine Release Evoked by Abused Substances Requires Cannabinoid-3290 Transient surges of dopamine in the nucleus accumbens are associated with drug seeking. Using a voltammetric of dopamine concentration transients caused by acute doses of nicotine, ethanol, and cocaine in the nucleus

RationaleDopamine (DA) activity in the nucleus accumbens (NAc) is related to the general motivational effects of rewarding stimuli. Dickinson and colleagues have shown that initial acquisition of instrumental responding reflects action�outcome relationships based on instrumental incentive learning, which establishes the value of an outcome. Given that ...

The fast sampling rates of fast scan cyclic voltammetry make it a favorable method for measuring changes in brain monoamine release and uptake kinetics in slice, anesthetized, and freely moving preparations. The most common analysis technique for evaluating changes in dopamine signaling uses well-established Michaelis-Menten kinetic methods that can accurately model ...

RationalExposing animal models of mental illness to addictive drugs provides an approach to understanding the neural etiology of dual diagnosis disorders. Previous studies have shown that neonatal ventral hippocampal lesions (NVHL) in rats produce features of both schizophrenia and addiction vulnerability.ObjectiveThis study investigated ventral and dorsal striatal dopamine ...

The effects of local perfusion of the ventral tegmental area (VTA) with N-methyl-D-aspartic acid (NMDA) on extracellular dopamine concentrations in the nucleus accumbens were investigated by using in vivo microdialysis in halothane anaesthetized rats. The electrophysiological response of VTA dopamine neurons to NMDA were also assessed ...

REVIEW Linking nucleus accumbens dopamine and blood oxygenation Brian Knutson & Sasha E. B. Gibbs-Verlag 2007 Abstract Rationale Animal research suggests that anticipation of reward can elicit dopamine in the NAcc. However, the physiolog- ical relationship between dopamine release and BOLD signal increases

Lack of Cocaine Effect on Dopamine Clearance in the Core and Shell of the Nucleus Accumbens Carolina 27157 Cocaine produces its reinforcing effects primarily by inhibiting the dopamine transporter). Surprisingly, in mice genetically lacking the DAT, cocaine was still able to elevate DA in the nucleus

Implications for intracranial self-stimulation Simultaneous dopamine and single-unit recordings.pnas.org/misc/reprints.shtml To order reprints, see: Notes: #12;Simultaneous dopamine and single-unit recordings reveal accumbens GABAergic this pathway use a variety of neurotransmitters including dopamine and GABA. For ...

Dynamic changes in accumbens dopamine correlate with learning during intracranial self University of New Jersey, Piscataway, NJ, April 23, 2008 (received for review December 4, 2007) Dopamine in extracellular dopamine were measured during ICSS in the rat NAc shell with fast-scan cyclic voltammetry

Dopamine release is heterogeneous within microenvironments of the rat nucleus accumbens R. Mark sensor technology coupled with principal component regression to examine the dynamics of dopamine dimensions and provides high temporal (0.1 s) resolution. At select locations spontaneous dopamine transient

A growing body of evidence suggests that several protein kinases are involved in the expression of pharmacological actions induced by a psychostimulant methamphetamine. The present study was designed to investigate the role of the Rho/Rho-associated kinase (ROCK)-dependent pathway in the expression of the increase in extracellular levels of dopamine in the nucleus ...

Acetylcholine (ACh) regulates many key functions of the CNS by activating cell surface receptors referred to as muscarinic ACh receptors (M₁�M₅ mAChRs). Like other mAChR subtypes, the M₄ mAChR is widely expressed in different regions of the forebrain. Interestingly, M₄ mAChRs are coexpressed with ...

The amphetamine derivative 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) reverses dopamine and serotonin transporters to produce efflux of dopamine and serotonin, respectively, in regions of the brain that have been implicated in reward. However, the role of serotonin/dopamine interactions in the behavioral ...

SYSTEMIC AND INTRA-ACCUMBENS ADMINISTRATION OF AMPHETAMINE DIFFERENTIALLY AFFECTS CORTICAL experiments tested the hypothesis that the amphetamine-induced increase in dopamine release in the nucleus amphetamine to stimulate cortical acetylcholine release. The effects of systemic or intra

T-type calcium channels are important in burst firing and expressed in brain regions implicated in schizophrenia. Therefore, we examined the effects of novel selective T-type calcium channel antagonists in preclinical assays predictive of antipsychotic-like activity. TTA-A2 blocked the psychostimulant effects of amphetamine and MK-801 and decreased conditioned avoidance responding. These effects ...

Adipocytes produce the hormone, leptin, in proportion to fat mass to signal the status of body energy stores to the central nervous system, thereby modulating food intake and energy homeostasis. In addition to controlling satiety, leptin suppresses the reward value of food, which is controlled by the mesolimbic dopamine (DA) system. Previous results from leptin-deficient ob/ob ...

Adipocytes produce the hormone, leptin, in proportion to fat mass to signal the status of body energy stores to the central nervous system, thereby modulating food intake and energy homeostasis. In addition to controlling satiety, leptin suppresses the reward value of food, which is controlled by the mesolimbic dopamine (DA) system. Previous results from leptin-deficient ob/ob ...

Cocaine and Amphetamine Increase Extracellular Dopamine in the Nucleus Accumbens of Mice Lacking dopamine in the dorsal striatum. Here we report that, in DAT-KO mice, cocaine and amphetamine increase; cocaine; amphetamine; reboxetine Cocaine and amphetamine psychostimulants are abused by hu- mans (Johanson

Subsecond fluctuations in dopamine (dopamine transients) in the nucleus accumbens are often time-locked to rewards and cues and provide an important learning signal during reward processing. As the mesolimbic dopamine system undergoes dynamic changes during adolescence in the rat, it is possible that ...

Conditions of increased cognitive or emotional demand activate dopamine release in a regionally selective manner. Whereas the brief millisecond response of dopamine neurons to salient stimuli suggests that dopamine�s influence on behaviour may be limited to signalling certain cues, the prolonged availability of ...

Receptor-specific compounds were applied by retrograde microdialysis to the ventral tegmental area (VTA) of the rat brain. The effect of the intrategmental infusions on extracellular dopamine in the ipsilateral nucleus accumbens were recorded with a second microdialysis probe. Intrategmental infusion of muscimol (10-40 microM) or baclofen (50 microM) ...

Dopamine injected directly into the caudate--putamen, nucleus accumbens or tuberculum olfactorium of rat brain, following a nialamide pretreatment, caused dose-dependent hyperactivity. The hyperactivity was more intense after injections into the nucleus accumbens, but was limited by the development of stereotyped biting when larger ...

In Sprague-Dawley rats in was shown by means of in vivo microdialysis combined with HPLC-EC analysis that the blockade of D2-dopamine receptors of the n. accumbens by raclopride (10 microM) completely prevents a decrease in accumbal extracellular glutamate level induced by food intake. PMID:11548610

Dopamine released in the nucleus accumbens is thought to contribute to the decision to exert effort to seek reward. This hypothesis is supported by findings that performance of tasks requiring higher levels of effort is more susceptible to disruption by manipulations that reduce accumbens dopamine function than ...

Dopamine released in the nucleus accumbens is thought to contribute to the decision to exert effort to seek reward. This hypothesis is supported by findings that performance of tasks requiring higher levels of effort is more susceptible to disruption by manipulations that reduce accumbens dopamine function than ...

The aim of this investigation was a neurochemical study of the effect of agonists of different types of GABA receptors - muscimol (type A receptor), baclofen (type B receptor), delta-aminolevulinic acid (DALA; GABA autoreceptor), and also of GABA itself - on tritium-labelled dopamine release, stimulated by potassium cations, from synaptosomes of the nuclei ...

Dopamine D5 Receptors in Nucleus Accumbens Contribute to the Detection of Cocaine in Rats the euphoric and stimulatory effects of cocaine in humans and rats. In the present study, rats trained to discriminate the presence of cocaine (10 mg/kg) from its absence were used to analyze the functional

Dopamine D2 and D3 autoreceptors are located on pre-synaptic terminals and are known to control the release and synthesis of dopamine. Dopamine D3 receptors have a fairly restricted pattern of expression in the mammalian brain. Their localization in the nucleus accumbens core and shell is of particular interest ...

The influence of dopamine D1- and D2-like receptors blockage on glutamate level in the n. accumbens of Sprague-Dawly rats during feeding was investigated by in vivo microdialysis combined with HPLC-EC analysis. Food intake resulted in a decrease in extracellular glutamate level. Infusion of D1-like dopamine receptor-blocker (SCH-23390, ...

Neural encoding of cocaine-seeking behavior is coincident with phasic dopamine release, neurotransmission, rat, reward Abstract Mesolimbic dopamine neurons projecting from the ventral tegmental area, the precise role of rapid (subsecond) dopamine release within the primary subregions of the NAc (the core

Neuron Report Coordinated Accumbal Dopamine Release and Neural Activity Drive Goal such as the nucleus accumbens (NAc). However, a direct role of dopamine in ICSS-mediated reward has been questioned that, at certain sites, the onset of anticipatory dopamine surges and changes in neuronal firing

Although progress has been made identifying neural mechanisms underlying ethanol's primary reinforcing effects, few studies have examined the mechanisms mediating ethanol-induced conditioned effects. A recent lesion study suggests that expression of ethanol-conditioned behaviors depends upon an intact amygdala and nucleus accumbens core. However, specific mechanisms within ...

Preclinical data have shown that addition of the selective norepinephrine transporter (NET) inhibitor reboxetine increases the antipsychotic-like effect of the D_2/3 antagonist raclopride and, in parallel, enhances cortical dopamine output. Subsequent clinical results suggested that adding reboxetine to stable treatments with various antipsychotic drugs ...

The mesoaccumbens dopamine system is intricately in-volved in the locomotor stimulation produced by cocaine and sensitization of this effect following repeated cocaine administration. The mechanisms responsible for the ex-pression of sensitized locomotion appear to involve alter-ations in both presynaptic (increased dopamine release) and postsynaptic ...

The inhibitory effects of 4-phenyl-1,2,3,4-tetrahydroisoquinoline (4-PTIQ) on methamphetamine-induced increases in dopamine and locomotion were investigated. Methamphetamine hydrochloride (10 micrograms) microinjected into the nucleus accumbens increased both locomotor activity and extracellular dopamine levels, measured by the brain ...

Increased caloric intake in dietary obesity could be driven by central mechanisms that regulate reward-seeking behavior. The mesolimbic dopamine system, and the nucleus accumbens in particular, underlies both food and drug reward. We investigated whether rat dietary obesity is linked to changes in dopaminergic neurotransmission in that region. ...

Increased caloric intake in dietary obesity could be driven by central mechanisms that regulate reward-seeking behavior. The mesolimbic dopamine system, and the nucleus accumbens in particular, underlies both food and drug reward. We investigated whether rat dietary obesity is linked to changes in dopaminergic neurotransmission in that region. ...

The present studies were conducted to investigate the relationship between discriminative stimulus effects of indirectly acting monoaminergic psychostimulants and their ability to increase extracellular levels of dopamine (DA) in the nucleus accumbens (NAcb) shell. First, the behavioral effects of methamphetamine (MA), cocaine (COC), ...

To date, there are no effective pharmacotherapies for treating psychostimulant abuse. Previous preclinical and clinical studies have shown that continuous treatment with the monoamine releaser amphetamine reduces cocaine self-administration, but amphetamine selectively targets the dopamine system and is reinforcing. In the present study, we examined the consequences of ...

To date, there are no effective pharmacotherapies for treating psychostimulant abuse. Previous preclinical and clinical studies have shown that continuous treatment with the monoamine releaser amphetamine reduces cocaine self-administration, but amphetamine selectively targets the dopamine system and is reinforcing. In the present study, we examined the consequences of ...

1. The effect of single and repeated (once daily for 23 days) oral doses of 20 and 60 mg kg-1 clozapine on dopamine release and metabolism were studied by intracerebral dialysis in the striatum and nucleus accumbens of conscious rats. 2. The basal output of dopamine, dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in the ...

The objective of these studies was to pharmacologically characterize the mechanism responsible for a folate-induced stimulation of locomotor activity in rats after bilateral injection into the nucleus accumbens region of the brain. Folic acid (FA) and 5-formyltetrahydrofolic acid (FTHF) produced this hypermotility response after intra-accumbens injection, ...

The involvement of dopamine within the nucleus accumbens in the formation and maintenance of pair bonds was assessed in a series of experiments using the monogamous prairie vole. We show that dopamine transmission that promotes pair bond formation occurs within the rostral shell of the nucleus accumbens, but not in ...

1. Fast cyclic voltammetry at carbon fibre microelectrodes was used to study the effects of several dopamine antagonists upon stimulated dopamine release in the rat striatum and nucleus accumbens. 2. In both nuclei, stimulated dopamine release was increased by D2-receptor-selective and mixed D1/D2-receptor ...

The dopamine reuptake inhibitor bupropion has clinically been proven to improve depression and treatment-resistant depression. We examined its influence on the duration of immobility during the forced swim test in adrenocorticotropic hormone (ACTH)-treated rats and further analyzed the possible role of dopamine receptors in this effect. Additionally, the ...

The mesolimbic dopaminergic system, especially the nucleus accumbens, has received attention for its involvement in the reinforcing and addictive properties of cocaine and other drugs of abuse. It is generally accepted that the ability of cocaine to inhibit the dopamine transporter (DAT) is directly related to its reinforcing actions. However, mice with a ...

Previous Exposure to Amphetamine Enhances the Subsequent Locomotor Response to a D1 Dopamine of locomo- tor sensitization to amphetamine (AMPH) was investigated in rats. Rats were preexposed to either dopamine receptors; glutamate; nucleus accumbens; amphetamine; sensitization; lo- comotor activity; L

The highly selective delta opioid agonist, SNC80, elicits dopamine-related behaviors including locomotor stimulation and conditioned place-preference. In contrast, it has been reported that SNC80 fails to promote dopamine efflux from the striatum of freely moving rats. However, SNC80 does enhance behavioral responses to the stimulants, ...

). The other treatments already available (methadone, buprenorphine) mayCho et al. 1997 also have abuse by nitrous oxide in mice. Neuroscience. 149: 477- 486 Boothby LA , Doering PL 2007; Buprenorphine

The release of endogenous dopamine and norepinephrine from six brain regions (cortex, hippocampus, hypothalamus, striatum, s. nigra, n. accumbens-o.tubercle) of chronically lead-exposed rats was compared to release from controls. Prenatal and postnatal ch...

Three experiments used rats to investigate the role of dopamine activity in learning to inhibit conditioned fear responses (freezing) in extinction. In Experiment 1, rats systemically injected with the D2 dopamine antagonist, haloperidol, froze more across multiple extinction sessions and on a drug-free retention test than control rats. In Experiment 2, ...

ContextModafinil, a wake-promoting drug used to treat narcolepsy, is increasingly being used as a cognitive enhancer. Although initially launched as distinct from stimulants that increase extracellular dopamine by targeting dopamine transporters, recent preclinical studies suggest otherwise.ObjectiveTo measure the acute effects of modafinil at doses used ...

The effect of excercise on brain function was investigated through animal experiments. Exercise leads to increased serum calcium levels, and the calcium is transported to the brain. This in turn enhances brain dopamine synthesis through a calmodulin-dependent system, and increased dopamine levels regulate various brain functions. There are abnormally low ...

We report a reliable 5-min on-line monitoring of dopamine released from the dorsal striatum and the nucleus accumbens of rats using in vivo brain microdialysis. The detection limit for dopamine was approximately 20 fg in a 10-microl injection sample using high-performance liquid chromatography with electrochemical detection set-up. ...

In postmortem samples of caudate nucleus and nucleus accumbens from 48 schizophrenic patients, there were significant increases in both the maximum number of binding sites (Bmax) and the apparent dissociation constant (KD) for tritiated spiperone. The increase in apparent KD probably reflects the presence of residual neuroleptic drugs, but changes in Bmax for tritiated ...

1. Fast cyclic voltammetry at carbon fibre microelectrodes was used in rats anaesthetized with chloral hydrate to monitor dopamine release in the caudate and nucleus accumbens evoked by electrical stimulation of the median forebrain bundle. Stimulation trains (50 Hz sinusoidal current, 100 +/- 10 microA r.m.s., 2s duration) were repeated every 5 min ...

Subsecond fluctuations in dopamine (dopamine transients) in the nucleus accumbens are often time-locked to rewards and cues and provide an important learning signal during reward processing. As the mesolimbic dopamine system undergoes dynamic changes during adolescence in the rat, it is possible that ...

Psychotropic analgesic nitrous oxide (PAN) has been used successfully in the treatment of alcohol and drug withdrawal in > 15,000 cases. It is an opioid and thus the first gaseous member of the opioid family. We propose the existence of two mutually antagonistic opioid systems as underlying addictive withdrawal states; mu and kappa. PAN as a multipotent opioid activates these systems. ...

The effects of the delta2-opioid receptor agonist, deltorphin II, on extracellular levels of dopamine in the rat nucleus accumbens were investigated in awake animals by in vivo brain microdialysis. In agreement with previous studies, perfusion of deltorphin II (50.0 nmol) into the nucleus accumbens significantly increased the ...

Previous studies have indicated that cocaine binding sites contain both high- and low-affinity binding components and have actions not related to dopamine uptake inhibition. Therefore, it has been studied if concentrations of cocaine in the range of 0.1-100 nM can affect not only dopamine uptake but also the quinpirole-induced inhibition of the K(+)-evoked ...

Isolation of the rat pup from the nest and dam for one hour per day from PN 2-9 is a useful paradigm for producing stress in the neonate. These previously isolated rats respond to an amphetamine challenge with alterations in activity at the juvenile stage or as adults. Furthermore, when dopamine release is measured in the nucleus accumbens, juveniles ...