751
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The Substance Use Risk Profile Scale: a scale measuring traits linked to reinforcement-specific substance use profiles. Addict Behav 2009; 34:1042-55. [PMID: 19683400 DOI: 10.1016/j.addbeh.2009.07.001] [Citation(s) in RCA: 349] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2008] [Revised: 06/10/2009] [Accepted: 07/01/2009] [Indexed: 01/19/2023]
Abstract
The Substance Use Risk Profile Scale (SURPS) is based on a model of personality risk for substance abuse in which four personality dimensions (hopelessness, anxiety sensitivity, impulsivity, and sensation seeking) are hypothesized to differentially relate to specific patterns of substance use. The current series of studies is a preliminary exploration of the psychometric properties of the SURPS in two populations (undergraduate and high school students). In study 1, an analysis of the internal structure of two versions of the SURPS shows that the abbreviated version best reflects the 4-factor structure. Concurrent, discriminant, and incremental validity of the SURPS is supported by convergent/divergent relationships between the SURPS subscales and other theoretically relevant personality and drug use criterion measures. In Study 2, the factorial structure of the SURPS is confirmed and evidence is provided for its test-retest reliability and validity with respect to measuring personality vulnerability to reinforcement-specific substance use patterns. In Study 3, the SURPS was administered in a more youthful population to test its sensitivity in identifying younger problematic drinkers. The results from the current series of studies demonstrate support for the reliability and construct validity of the SURPS, and suggest that four personality dimensions may be linked to substance-related behavior through different reinforcement processes. This brief assessment tool may have important implications for clinicians and future research.
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752
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Hamidovic A, Dlugos A, Skol A, Palmer AA, de Wit H. Evaluation of genetic variability in the dopamine receptor D2 in relation to behavioral inhibition and impulsivity/sensation seeking: an exploratory study with d-amphetamine in healthy participants. Exp Clin Psychopharmacol 2009; 17:374-83. [PMID: 19968402 PMCID: PMC2879583 DOI: 10.1037/a0017840] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The dopamine D2 receptor (DRD2) appears to be involved in impulsive behaviors, and particularly in behavioral inhibition. We sought to determine whether inhibition and impulsivity were related to genetic polymorphisms in the DRD2 gene (DRD2) in healthy volunteers (N = 93). Participants received placebo or d-amphetamine in random order. They performed the stop task, measuring behavioral inhibition, and rated their mood states on each session. They also completed the Zuckerman-Kuhlman Personality Questionnaire, including an Impulsivity subscale. We investigated the association between 12 single nucleotide polymorphisms (SNPs) and haplotypes in DRD2 and stop task performance in the nondrug (i.e., placebo) session and on the personality measure of impulsivity. We secondarily evaluated the DRD2 SNPs in relation to response to d-amphetamine on stop task performance and mood ratings. Mood was not related to genotypes in either the drug free condition or in response to drug. However, 2 SNPs, rs4648317 and rs12364283, and a haplotype block consisting of those SNPs, were associated with better performance on the stop task in the drug free condition and lower scores on the Impulsivity subscale. We also found that rs12364283 was associated with effects of d-amphetamine on stop task performance: d-amphetamine decreased stop reaction time (RT) in the A/A group but increased stop RT in the combined A/G + G/G genotype. Of the SNPs we evaluated, rs12364283, which has been associated with DRD2 expression, was the most significantly associated with inhibition and impulsivity. The significant relationship between DRD2 genotype and both behavioral inhibition and impulsivity suggests a possible common genetic influence on behavioral and self-report measures of impulsivity.
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Affiliation(s)
- Ajna Hamidovic
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago
| | - Andrea Dlugos
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago
| | - Andrew Skol
- Department of Medicine, University of Chicago
| | - Abraham A. Palmer
- Department of Psychiatry and Behavioral Neuroscience and Department of Human Genetics, The University of Chicago
| | - Harriet de Wit
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago
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753
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Yan TC, Hunt SP, Stanford SC. Behavioural and neurochemical abnormalities in mice lacking functional tachykinin-1 (NK1) receptors: A model of attention deficit hyperactivity disorder. Neuropharmacology 2009; 57:627-35. [DOI: 10.1016/j.neuropharm.2009.08.021] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Revised: 08/12/2009] [Accepted: 08/13/2009] [Indexed: 01/23/2023]
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754
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Morris G, Schmidt R, Bergman H. Striatal action-learning based on dopamine concentration. Exp Brain Res 2009; 200:307-17. [PMID: 19904530 DOI: 10.1007/s00221-009-2060-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2009] [Accepted: 10/08/2009] [Indexed: 11/25/2022]
Abstract
The reinforcement learning hypothesis of dopamine function predicts that dopamine acts as a teaching signal by governing synaptic plasticity in the striatum. Induced changes in synaptic strength enable the cortico-striatal network to learn a mapping between situations and actions that lead to a reward. A review of the relevant neurophysiology of dopamine function in the cortico-striatal network and the machine reinforcement learning hypothesis reveals an apparent mismatch with recent electrophysiological studies. It was found that in addition to the well-described reward-related responses, a subpopulation of dopamine neurons also exhibits phasic responses to aversive stimuli or to cues predicting aversive stimuli. Obviously, actions that lead to aversive events should not be reinforced. However, published data suggest that the phasic responses of dopamine neurons to reward-related stimuli have a higher firing rate and have a longer duration than phasic responses of dopamine neurons to aversion-related stimuli. We propose that based on different dopamine concentrations, the target structures are able to decode reward-related dopamine from aversion-related dopamine responses. Thereby, the learning of actions in the basal-ganglia network integrates information about both costs and benefits. This hypothesis predicts that dopamine concentration should be a crucial parameter for plasticity rules at cortico-striatal synapses. Recent in vitro studies on cortico-striatal synaptic plasticity rules support a striatal action-learning scheme where during reward-related dopamine release dopamine-dependent forms of synaptic plasticity occur, while during aversion-related dopamine release the dopamine concentration only allows dopamine-independent forms of synaptic plasticity to occur.
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Affiliation(s)
- Genela Morris
- Department of Neurobiology and Ethology, Haifa University, Haifa, Israel
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755
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Smillie LD, Cooper AJ, Proitsi P, Powell JF, Pickering AD. Variation in DRD2 dopamine gene predicts Extraverted personality. Neurosci Lett 2009; 468:234-7. [PMID: 19897017 DOI: 10.1016/j.neulet.2009.10.095] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2009] [Revised: 10/28/2009] [Accepted: 10/30/2009] [Indexed: 11/25/2022]
Abstract
Quantitative geneticists estimate the heritability of Extraverted personality to be around 40-60%. Theory and research which links Extraversion with variation in dopaminergic function suggests that dopaminergic genes should be a start-point for molecular genetic investigations of this trait. Recent endeavours in this area have met with some encouragement but also setbacks. In this study, we investigate the relationship between Extraversion and the DRD2 TaqIA/ANKK1 polymorphism in 224 university students. Presence of at least one copy of the A1 allele was associated with significantly higher Extraversion. The robustness of this finding was confirmed through bootstrap analysis. Findings are discussed in relation to the broader literature, in particular, methodological issues which may have obscured this finding in previous research.
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756
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Potenza MN, Taylor JR. Found in translation: understanding impulsivity and related constructs through integrative preclinical and clinical research. Biol Psychiatry 2009; 66:714-6. [PMID: 19800484 PMCID: PMC2801557 DOI: 10.1016/j.biopsych.2009.08.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2009] [Accepted: 08/06/2009] [Indexed: 11/19/2022]
Affiliation(s)
- Marc N Potenza
- Departments of Psychiatry and the Child Study Center, Yale University School of Medicine, New Haven, Connecticut 06519, USA.
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757
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Love TM, Stohler CS, Zubieta JK. Positron emission tomography measures of endogenous opioid neurotransmission and impulsiveness traits in humans. ACTA ACUST UNITED AC 2009; 66:1124-34. [PMID: 19805703 DOI: 10.1001/archgenpsychiatry.2009.134] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
CONTEXT The endogenous opioid system and opioid mu receptors (mu-receptors) are known to interface environmental events, positive (eg, relevant emotional stimuli) and negative (eg, stressors), with pertinent behavioral responses and to regulate motivated behavior. OBJECTIVE To examine the degree to which trait impulsiveness (the tendency to act on cravings and urges rather than to delay gratification) is predicted by baseline mu-receptor availability or the response of this system to a standardized, experientially matched stressor. DESIGN, SETTING, AND PATIENTS Nineteen young healthy male volunteers completed a personality questionnaire (NEO Personality Inventory, Revised) and underwent positron emission tomography scans with the mu-receptor-selective radiotracer carfentanil labeled with carbon 11. Measures of receptor concentrations were obtained at rest and during receipt of an experimentally maintained pain stressor of matched intensity between subjects. MAIN OUTCOME MEASURES Baseline receptor levels and stress-induced activation of mu-opioid system neurotransmission compared between subjects scoring above and below the population median on the NEO Personality Inventory, Revised, impulsiveness subscale and the orthogonal dimension (deliberation) expected to interact with it. RESULTS High impulsiveness and low deliberation scores were associated with significantly higher regional mu-receptor concentrations and greater stress-induced endogenous opioid system activation. Effects were obtained in the prefrontal and orbitofrontal cortices, anterior cingulate, thalamus, nucleus accumbens, and basolateral amygdala-all regions involved in motivated behavior and the effects of drugs of abuse. Availability of the mu-receptor and the magnitude of stress-induced endogenous opioid activation in these regions accounted for 17% to 49% of the variance in these personality traits. CONCLUSIONS Individual differences in the function of the endogenous mu-receptor system predict personality traits that confer vulnerability to or resiliency against risky behaviors such as the predisposition to develop substance use disorders. These personality traits are also implicated in psychopathological states (eg, personality disorders) in which variations in the function of this neurotransmitter system also may play a role.
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Affiliation(s)
- Tiffany M Love
- The Molecular & Behavioral Neuroscience Institute, University of Michigan, 205 Zina Pitcher Pl, Ann Arbor, MI 48109-0720, USA
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758
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Du C, Tully M, Volkow ND, Schiffer WK, Yu M, Luo Z, Koretsky AP, Benveniste H. Differential effects of anesthetics on cocaine's pharmacokinetic and pharmacodynamic effects in brain. Eur J Neurosci 2009; 30:1565-75. [PMID: 19821842 DOI: 10.1111/j.1460-9568.2009.06931.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Most studies of the effect of cocaine on brain activity in laboratory animals are preformed under anesthesia, which could potentially affect the physiological responses to cocaine. Here we assessed the effects of two commonly used anesthetics [alpha-chloralose (alpha-CHLOR) and isofluorane (ISO)] on the effects of acute cocaine (1 mg/kg i.v.) on cerebral blood flow (CBF), cerebral blood volume (CBV), and tissue hemoglobin oxygenation (S(t)O(2)) using optical techniques and cocaine's pharmacokinetics (PK) and binding in the rat brain using (PET) and [(11)C]cocaine. We showed that acute cocaine at a dose abused by cocaine abusers decreased CBF, CBV and S(t)O(2) in rats anesthetized with ISO, whereas it increased these parameters in rats anesthetized with alpha-CHLOR. Importantly, in ISO-anesthetized animals cocaine-induced changes in CBF and S(t)O(2) were coupled, whereas for alpha-CHLOR these measures were uncoupled. Moreover, the clearance of [(11)C]cocaine from the brain was faster for ISO (peak half-clearance 15.8 +/- 2.8 min) than for alpha-CHLOR (27.5 +/- 0.6 min), and the ratio of specific to non-specific binding of [(11)C]cocaine in the brain was higher for ISO- (3.37 +/- 0.32) than for alpha-CHLOR-anesthetized rats (2.24 +/- 0.4). For both anesthetics, cocaine-induced changes in CBF followed the fast uptake of [(11)C]cocaine in the brain (peaking at approximately 2.5-4 min), but only for ISO did the duration of the CBV and S(t)O(2) changes correspond to the rate of [(11)C]cocaine's clearance from the brain. These results demonstrate that anesthetics influence cocaine's hemodynamic and metabolic changes in the brain, and its binding and PK, which highlights the need to better understand the interactions between anesthetics and pharmacological challenges in brain functional imaging studies.
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Affiliation(s)
- Congwu Du
- Department of Anesthesiology, State University of New York at Stony Brook, Stony Brook, NY, USA.
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759
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Tantawy MN, Jones CK, Baldwin RM, Ansari MS, Conn PJ, Kessler RM, Peterson TE. [(18)F]Fallypride dopamine D2 receptor studies using delayed microPET scans and a modified Logan plot. Nucl Med Biol 2009; 36:931-40. [PMID: 19875049 DOI: 10.1016/j.nucmedbio.2009.06.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2009] [Revised: 06/02/2009] [Accepted: 06/22/2009] [Indexed: 10/20/2022]
Abstract
UNLABELLED [(18)F]Fallypride PET studies can be used to estimate the nondisplaceable binding potential (BP(ND)) in vivo of dopamine D2/D3 receptor-rich regions of the brain. These studies often take considerable time, up to >or=2 h, limiting the throughput. In this work, we investigated whether limited-duration scans performed subsequent to tracer administration yielded stable BP(ND) estimates. In particular, we applied a modified version of the Logan plot method on the last 60 min of 120-min data and compared the results to those from analysis of the full data set. METHODS Fourteen male Sprague-Dawley rats were injected with [(18)F]fallypride intravenously while under isoflurane anesthesia, and dynamic data were acquired on the microPET Focus 220 scanner for 120 min. The distribution volume ratio (DVR=BP(ND)+1) was calculated from a Logan plot using 120 min of data and from a modified version using only the last 60 min. Three of these rats were imaged again on a second day to test the reproducibility. A two-tissue compartment model also was used to fit the time-activity curves (TACs) of the 120-min scans to estimate the parameters K(1), k(2), k(on), k(4) and B(max). These parameters were then used to simulate similar TACs while changing k(on) to reflect changes in the dopaminergic system. The simulated TACs were used as a means for exploring the differences in DVR estimates between the last 60 min only and the full 120 min of simulated data. RESULTS The average DVR from the full 120-min scans was 13.8+/-0.9, whereas the average DVR estimated from only the last 60 min of data (DVR') was 16.3+/-1.0. The DVR estimates showed good reproducibility in the three rats (mean DVR=13.8+/-1.5 on Day 1 and DVR=13.8+/-0.9 on Day 2). The simulations showed that the relationship between DVR' and DVR estimates follows a semilinear form with varying k(on). CONCLUSION Although the BP(ND) estimates are slightly overestimated in a delayed scan mode (i.e., no initial radiotracer uptake measurements) compared to a full scan, this overestimation depends primarily on k(3) (approximately k(on) x B(max)) and has been evaluated in this work for a wide range of k(on) values using simulated TACs. In particular, the sensitivity of DVR' to changes in k(on) is similar to that of DVR. This method of delayed scans eliminates the necessity of imaging during the initial uptake of the radiotracer and, thus, can be used to increase the throughput of studies.
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Affiliation(s)
- Mohammed N Tantawy
- Department of Radiology and Radiological Sciences, Vanderbilt University Institute of Imaging Science, Nashville, TN 37232, USA.
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760
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Carroll ME, Anker JJ, Perry JL. Modeling risk factors for nicotine and other drug abuse in the preclinical laboratory. Drug Alcohol Depend 2009; 104 Suppl 1:S70-8. [PMID: 19136222 DOI: 10.1016/j.drugalcdep.2008.11.011] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2008] [Revised: 11/12/2008] [Accepted: 11/19/2008] [Indexed: 01/24/2023]
Abstract
Risk factors that predict vulnerability for nicotine and other drug abuse have been identified using preclinical models, and there is close agreement with clinical and epidemiological studies. The major risk factors to be discussed are age, sex/hormonal status, impulsivity, sweet-liking, novelty reactivity, proclivity for exercise, and environmental impoverishment (vs. enrichment). This discussion will focus on factors that preclinical research has determined are strong and translatable predictors of nicotine and other drug abuse. An advantage of using preclinical models is that prospective, longitudinal studies and within-subject designs can be used to reveal risk factors that are diverse yet maintain unique characteristics. The many interrelationships among these factors lead to an additive vulnerability that increases the predictability that drug abuse will occur. A feature that these risk factors have in common is that they consistently predict vulnerability to drug abuse over critical transition phases of addiction that are difficult to examine prospectively in humans, such as acquisition, escalation, and reinstatement of drug-seeking after abstinence (relapse). The models offer valuable information that has been transferred to effective prevention and treatment strategies for smoking and other drug abuse in humans.
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Affiliation(s)
- Marilyn E Carroll
- University of Minnesota, Department of Psychiatry, Minneapolis, MN 55455, USA.
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761
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Loss of dendrite stabilization by the Abl-related gene (Arg) kinase regulates behavioral flexibility and sensitivity to cocaine. Proc Natl Acad Sci U S A 2009; 106:16859-64. [PMID: 19805386 DOI: 10.1073/pnas.0902286106] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Adolescence is characterized by increased vulnerability to developing neuropsychiatric disorders and involves a period of prefrontal cortical dendritic refinement and synaptic pruning that culminates in cytoskeletal stabilization in adulthood. The Abl-related gene (Arg) acts through p190RhoGAP to inhibit the RhoA GTPase and stabilize cortical dendritic arbors beginning in adolescence. Cortical axons, dendrites, and synapses develop normally in Arg-deficient (arg(-/-)) mice, but adult dendrites destabilize and regress; thus, arg(-/-) mice present a model of adolescent-onset dendritic simplification. We show that arg(-/-) mice are impaired in a reversal task and that deficits are grossly exacerbated by low-dose cocaine administration. Although ventral prefrontal dopamine D2 receptor levels predict "perseverative" error counts in wild-type mice, no such relationship is found in arg(-/-) mice. Moreover, arg(-/-) mice are insensitive to the disruptive effects of the D2/D3 antagonist haloperidol in reversal but show normal sensitivity to its locomotor-depressant actions. Arg deficiency and orbitofrontal cortical Arg inhibition via STI-571 infusion also enhance the psychomotor stimulant actions of cocaine. These findings provide evidence that stabilization of dendritic structure beginning in adolescence is critical for the development of adaptive and flexible behavior after cocaine exposure.
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762
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Volkow ND, Wang GJ, Kollins SH, Wigal TL, Newcorn JH, Telang F, Fowler JS, Zhu W, Logan J, Ma Y, Pradhan K, Wong C, Swanson JM. Evaluating dopamine reward pathway in ADHD: clinical implications. JAMA 2009; 302:1084-91. [PMID: 19738093 PMCID: PMC2958516 DOI: 10.1001/jama.2009.1308] [Citation(s) in RCA: 398] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
CONTEXT Attention-deficit/hyperactivity disorder (ADHD)--characterized by symptoms of inattention and hyperactivity-impulsivity--is the most prevalent childhood psychiatric disorder that frequently persists into adulthood, and there is increasing evidence of reward-motivation deficits in this disorder. OBJECTIVE To evaluate biological bases that might underlie a reward/motivation deficit by imaging key components of the brain dopamine reward pathway (mesoaccumbens). DESIGN, SETTING, AND PARTICIPANTS We used positron emission tomography to measure dopamine synaptic markers (transporters and D(2)/D(3) receptors) in 53 nonmedicated adults with ADHD and 44 healthy controls between 2001-2009 at Brookhaven National Laboratory. MAIN OUTCOME MEASURES We measured specific binding of positron emission tomographic radioligands for dopamine transporters (DAT) using [(11)C]cocaine and for D(2)/D(3) receptors using [(11)C]raclopride, quantified as binding potential (distribution volume ratio -1). RESULTS For both ligands, statistical parametric mapping showed that specific binding was lower in ADHD than in controls (threshold for significance set at P < .005) in regions of the dopamine reward pathway in the left side of the brain. Region-of-interest analyses corroborated these findings. The mean (95% confidence interval [CI] of mean difference) for DAT in the nucleus accumbens for controls was 0.71 vs 0.63 for those with ADHD (95% CI, 0.03-0.13, P = .004) and in the midbrain for controls was 0.16 vs 0.09 for those with ADHD (95% CI, 0.03-0.12; P < or = .001); for D(2)/D(3) receptors, the mean accumbens for controls was 2.85 vs 2.68 for those with ADHD (95% CI, 0.06-0.30, P = .004); and in the midbrain, it was for controls 0.28 vs 0.18 for those with ADHD (95% CI, 0.02-0.17, P = .01). The analysis also corroborated differences in the left caudate: the mean DAT for controls was 0.66 vs 0.53 for those with ADHD (95% CI, 0.04-0.22; P = .003) and the mean D(2)/D(3) for controls was 2.80 vs 2.47 for those with ADHD (95% CI, 0.10-0.56; P = .005) and differences in D(2)/D(3) in the hypothalamic region, with controls having a mean of 0.12 vs 0.05 for those with ADHD (95% CI, 0.02-0.12; P = .004). Ratings of attention correlated with D(2)/D(3) in the accumbens (r = 0.35; 95% CI, 0.15-0.52; P = .001), midbrain (r = 0.35; 95% CI, 0.14-0.52; P = .001), caudate (r = 0.32; 95% CI, 0.11-0.50; P = .003), and hypothalamic (r = 0.31; CI, 0.10-0.49; P = .003) regions and with DAT in the midbrain (r = 0.37; 95% CI, 0.16-0.53; P < or = .001). CONCLUSION A reduction in dopamine synaptic markers associated with symptoms of inattention was shown in the dopamine reward pathway of participants with ADHD.
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Affiliation(s)
- Nora D Volkow
- National Institute on Drug Abuse, 6001 Executive Blvd, Room 5274, MSC 9581, Bethesda, MD 20892, USA.
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763
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Dopamine dysregulation syndrome and levodopa-induced dyskinesias in Parkinson disease: common consequences of anomalous forms of neural plasticity. Clin Neuropharmacol 2009; 32:22-7. [PMID: 18978500 DOI: 10.1097/wnf.0b013e3181634ea6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Four to 10% of patients with Parkinson disease and chronically treated with levodopa undergo an addictionlike behavioral disturbance named dopamine dysregulation syndrome (DDS). This article suggests that patients with Parkinson disease could be especially prone to develop DDS due to the dopamine deficiency and the "priming" of neural networks by the chronic use of drugs with a short half-life, such as levodopa. These suggestions are based on the clinical and molecular similarities between levodopa-induced dyskinesias and behavioral alterations seen in DDS and addiction to illegal drugs. Motor and behavioral abnormalities can be seen as the consequence of common mechanisms involving anomalous forms of neural plasticity. These forms affect parts of the cortical-basal ganglia-thalamocortical circuits that are topographically organized to differently modulate emotional and motor functions. Recent evidence using positron emission tomography provides support to this idea. By contrast, molecular data suggest that functional segregation may be lost in addiction, DDS, and dyskinesias. The existence of common pathogenic mechanisms for both phenomena could provide the basis for common therapeutic strategies.
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764
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Amphetamine decreases behavioral inhibition by stimulation of dopamine D2, but not D3, receptors. Behav Pharmacol 2009; 20:484-91. [DOI: 10.1097/fbp.0b013e3283305e3b] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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765
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Setlow B, Mendez IA, Mitchell MR, Simon NW. Effects of chronic administration of drugs of abuse on impulsive choice (delay discounting) in animal models. Behav Pharmacol 2009; 20:380-9. [PMID: 19667970 PMCID: PMC2874684 DOI: 10.1097/fbp.0b013e3283305eb4] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Drug-addicted individuals show high levels of impulsive choice, characterized by preference for small immediate over larger but delayed rewards. Although the causal relationship between chronic drug use and elevated impulsive choice in humans has been unclear, a small but growing body of literature over the past decade has shown that chronic drug administration in animal models can cause increases in impulsive choice, suggesting that a similar causal relationship may exist in human drug users. This article reviews this literature, with a particular focus on the effects of chronic cocaine administration, which have been most thoroughly characterized. The potential mechanisms of these effects are described in terms of drug-induced neural alterations in ventral striatal and prefrontal cortical brain systems. Some implications of this research for pharmacological treatment of drug-induced increases in impulsive choice are discussed, along with suggestions for future research in this area.
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Affiliation(s)
- Barry Setlow
- Behavioral and Cellular Neuroscience Program, Department of Psychology, Texas A&M University, College Station, Texas 77843-4235, USA.
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766
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Stress, genotype and norepinephrine in the prediction of mouse behavior using reinforcement learning. Nat Neurosci 2009; 12:1180-6. [DOI: 10.1038/nn.2374] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2009] [Accepted: 06/22/2009] [Indexed: 11/08/2022]
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767
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Haile CN, Kosten TR, Kosten TA. Pharmacogenetic treatments for drug addiction: cocaine, amphetamine and methamphetamine. THE AMERICAN JOURNAL OF DRUG AND ALCOHOL ABUSE 2009; 35:161-77. [PMID: 19462300 DOI: 10.1080/00952990902825447] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
BACKGROUND Pharmacogenetics uses genetic variation to predict individual differences in response to medications and holds much promise to improve treatment of addictive disorders. OBJECTIVES To review how genetic variation affects responses to cocaine, amphetamine, and methamphetamine and how this information may guide pharmacotherapy. METHODS We performed a cross-referenced literature search on pharmacogenetics, cocaine, amphetamine, and methamphetamine. RESULTS We describe functional genetic variants for enzymes dopamine-beta-hydroxylase (DbetaH), catechol-O-methyltransferase (COMT), and dopamine transporter (DAT1), dopamine D4 receptor, and brain-derived neurotrophic factor (BDNF). A single nucleotide polymorphism (SNP; C-1021T) in the DbetaH gene is relevant to paranoia associated with disulfiram pharmacotherapy for cocaine addiction. Individuals with variable number tandem repeats (VNTR) of the SLC6A3 gene 3'-untranslated region polymorphism of DAT1 have altered responses to drugs. The 10/10 repeat respond poorly to methylphenidate pharmacotherapy and the 9/9 DAT1 variant show blunted euphoria and physiological response to amphetamine. COMT, D4 receptor, and BDNF polymorphisms are linked to methamphetamine abuse and psychosis. CONCLUSIONS Disulfiram and methylphenidate pharmacotherapies for cocaine addiction are optimized by considering polymorphisms affecting DbetaH and DAT1 respectively. Altered subjective effects for amphetamine in DAT1 VNTR variants suggest a 'protected' phenotype. SCIENTIFIC SIGNIFICANCE Pharmacogenetic-based treatments for psychostimulant addiction are critical for successful treatment.
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Affiliation(s)
- Colin N Haile
- Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, and Michael E DeBakey VA Medical Center, Houston, Texas 77030, USA
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768
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Paloyelis Y, Asherson P, Kuntsi J. Are ADHD symptoms associated with delay aversion or choice impulsivity? A general population study. J Am Acad Child Adolesc Psychiatry 2009; 48:837-846. [PMID: 19564796 PMCID: PMC2788754 DOI: 10.1097/chi.0b013e3181ab8c97] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE The term delay aversion has been used both to describe a behavioral tendency of greater preference for smaller-immediate over larger-delayed rewards (choice impulsivity) and to refer to a secondary explanatory construct put forward by delay aversion theory. In this study, we examined the association of attention-deficit/hyperactivity disorder (ADHD) symptoms with choice impulsivity and tested the specific hypothesis derived from delay aversion theory. METHOD A total of 1,062 children aged 7.90 to 10.90 years (49% girls) made a fixed number of repeated choices between a smaller reward delivered immediately and a larger reward delivered after a delay (choice-delay task), under two conditions (including and excluding a postreward delay). We assessed the unique contribution of each ADHD symptom dimension to the prediction of choice impulsivity and delay aversion, controlling for age (or age and IQ). Sex effects were examined. RESULTS : Inattention ratings uniquely predicted preference for smaller-immediate rewards under both task conditions for both sexes. An index of delay aversion was associated with inattention only in boys; the effect size was small yet significant. Hyperactivity-impulsivity ratings were negatively associated with choice impulsivity in girls in the postreward delay condition, whereas no significant association with hyperactivity-impulsivity ratings was observed in boys. Categorical analyses using groups with high ADHD symptoms yielded similar results. CONCLUSIONS This is the first study to report a unique association between inattention symptoms and behavioral measures of choice impulsivity and delay aversion. The findings indicate the importance of the primary constitutional processes that underlie choice impulsivity and their potential role in behavioral inattention. Understanding the behavioral and brain processes underlying choice impulsivity may lead to the improved targeting of behavioral and pharmacological interventions.
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Affiliation(s)
- Yannis Paloyelis
- All of the authors are with the Medical Research Council Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, King's College London.
| | - Philip Asherson
- All of the authors are with the Medical Research Council Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, King's College London
| | - Jonna Kuntsi
- All of the authors are with the Medical Research Council Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, King's College London
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769
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Mobbs D, Hassabis D, Seymour B, Marchant JL, Weiskopf N, Dolan RJ, Frith CD. Choking on the money: reward-based performance decrements are associated with midbrain activity. Psychol Sci 2009; 20:955-62. [PMID: 19594859 PMCID: PMC2931754 DOI: 10.1111/j.1467-9280.2009.02399.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
A pernicious paradox in human motivation is the occasional reduced performance associated with tasks and situations that involve larger-than-average rewards. Three broad explanations that might account for such performance decrements are attentional competition (distraction theories), inhibition by conscious processes (explicit-monitoring theories), and excessive drive and arousal (overmotivation theories). Here, we report incentive-dependent performance decrements in humans in a reward-pursuit task; subjects were less successful in capturing a more valuable reward in a computerized maze. Concurrent functional magnetic resonance imaging revealed that increased activity in ventral midbrain, a brain area associated with incentive motivation and basic reward responding, correlated with both reduced number of captures and increased number of near-misses associated with imminent high rewards. These data cast light on the neurobiological basis of choking under pressure and are consistent with overmotivation accounts.
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Affiliation(s)
- Dean Mobbs
- Wellcome Trust Centre for Neuroimaging, Functional Imaging Laboratory, University College London, UK.
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770
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Prefrontal and striatal dopaminergic genes predict individual differences in exploration and exploitation. Nat Neurosci 2009; 12:1062-8. [PMID: 19620978 PMCID: PMC3062477 DOI: 10.1038/nn.2342] [Citation(s) in RCA: 311] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2009] [Accepted: 04/28/2009] [Indexed: 11/09/2022]
Abstract
The basal ganglia support learning to exploit decisions that have yielded positive outcomes in the past. In contrast, limited evidence implicates the prefrontal cortex in the process of making strategic exploratory decisions when the magnitude of potential outcomes is unknown. Here we examine neurogenetic contributions to individual differences in these distinct aspects of motivated human behavior, using a temporal decision-making task and computational analysis. We show that two genes controlling striatal dopamine function, DARPP-32 (also called PPP1R1B) and DRD2, are associated with exploitative learning to adjust response times incrementally as a function of positive and negative decision outcomes. In contrast, a gene primarily controlling prefrontal dopamine function (COMT) is associated with a particular type of 'directed exploration', in which exploratory decisions are made in proportion to Bayesian uncertainty about whether other choices might produce outcomes that are better than the status quo. Quantitative model fits reveal that genetic factors modulate independent parameters of a reinforcement learning system.
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771
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Oliver YP, Ripley TL, Stephens DN. Ethanol effects on impulsivity in two mouse strains: similarities to diazepam and ketamine. Psychopharmacology (Berl) 2009; 204:679-92. [PMID: 19263039 DOI: 10.1007/s00213-009-1500-0] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2008] [Accepted: 02/18/2009] [Indexed: 11/26/2022]
Abstract
RATIONALE The effects of ethanol on attention and impulsivity have been contradictory. OBJECTIVES The aim of the present investigation is to study the effects of acute ethanol administration in measures of attention and response control in the five-choice serial reaction time task (5-CSRTT) in two strains of mice, C57BL/6JOlaHsd and CD1. MATERIALS AND METHODS Mice were trained in the 5-CSRTT and then were injected intraperitoneally (i.p.) with 0, 0.5, 1 and 2 g/kg ethanol before testing under standard parameters and in a long inter-trial interval (ITI) session, which promotes the emergence of premature responses, a measure of poor inhibitory control. To examine if the effects of ethanol in the 5-CSRTT were due to its actions at GABA(A) receptors or at NMDA receptors, the GABA(A) receptor agonist diazepam (1 and 2 mg/kg, i.p.) and the non-competitive NMDA antagonist ketamine (10 and 20 mg/kg, i.p.) were tested in long ITI sessions. RESULTS Ethanol did not affect attention or impulsivity in the standard procedure, but increased premature responding in long ITI sessions. The effects of ethanol were mimicked by diazepam in both strains of mice, whereas ketamine increased premature responding only in the CD1 strain. CONCLUSIONS Ethanol's ability to increase impulsivity in the 5-CSRTT is mediated by both common and different neurotransmitter systems in the two strains of mice and is dependent on the task's parameters. Furthermore, ethanol did not decrease response accuracy, suggesting that attentional mechanisms are preserved after acute ethanol in mice and that the increases in impulsive behaviour are independent of attentional performance.
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Affiliation(s)
- Yolanda Peña Oliver
- Department of Psychology, University of Sussex, Falmer, Brighton, BN1 9QG, UK
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772
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Abstract
The core nature of nicotine dependence is evident in wide variations in how individuals become and remain smokers. Individuals with pre-existing behavioral traits are more likely to develop nicotine dependence and experience difficulty when attempting to quit. Many molecular factors likely contribute to individual variations in the development of nicotine dependence and behavioral traits in complex manners. However, the identification of such molecules has been hampered by the phenotypic complexity of nicotine dependence and the complex ways molecules affect elements of nicotine dependence. We hypothesize that nicotine dependence is, in part, a result of interactions between nicotine and pre-existing behavioral traits. This perspective suggests that the identification of the molecular bases of such pre-existing behavioral traits will contribute to the development of effective methods for reducing smoking dependence and for helping smokers to quit.
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Affiliation(s)
- N Hiroi
- Department of Psychiatry and Behavioral Sciences, Laboratory of Molecular Psychobiology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
| | - D Scott
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, USA
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773
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Lawrence AJ, Luty J, Bogdan NA, Sahakian BJ, Clark L. Problem gamblers share deficits in impulsive decision-making with alcohol-dependent individuals. Addiction 2009; 104:1006-15. [PMID: 19466924 PMCID: PMC2773538 DOI: 10.1111/j.1360-0443.2009.02533.x] [Citation(s) in RCA: 211] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS Problem gambling has been proposed to represent a 'behavioural addiction' that may provide key insights into vulnerability mechanisms underlying addiction in brains that are not affected by the damaging effects of drugs. Our aim was to investigate the neurocognitive profile of problem gambling in comparison with alcohol dependence. We reasoned that shared deficits across the two conditions may reflect underlying vulnerability mechanisms, whereas impairments specific to alcohol dependence may reflect cumulative effects of alcohol consumption. DESIGN Cross-sectional study. SETTING Out-patient addiction treatment centres and university behavioural testing facilities. PARTICIPANTS A naturalistic sample of 21 male problem and pathological gamblers, 21 male alcohol-dependent out-patients and 21 healthy male control participants. MEASUREMENTS Neurocognitive battery assessing decision-making, impulsivity and working memory. FINDINGS The problem gamblers and alcohol-dependent groups displayed impairments in risky decision-making and cognitive impulsivity relative to controls. Working memory deficits and slowed deliberation times were specific to the alcohol-dependent group. CONCLUSIONS Gambling and alcohol-dependent groups shared deficits in tasks linked to ventral prefrontal cortical dysfunction. Tasks loading on dorsolateral prefrontal cortex were selectively impaired in the alcohol-dependent group, presumably as a consequence of long-term alcohol use.
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Affiliation(s)
- Andrew J Lawrence
- Behavioural and Clinical Neuroscience Institute, University of CambridgeCambridge, UK,Department of Experimental Psychology, University of CambridgeCambridge, UK
| | - Jason Luty
- Southend Community Drug and Alcohol Service, South Essex Partnership NHS TrustEssex, UK
| | - Nadine A Bogdan
- Derwent Centre, North Essex Partnership Foundation TrustHarlow, Essex, UK
| | - Barbara J Sahakian
- Behavioural and Clinical Neuroscience Institute, University of CambridgeCambridge, UK,Department of Psychiatry, University of Cambridge School of Clinical MedicineCambridge, UK
| | - Luke Clark
- Behavioural and Clinical Neuroscience Institute, University of CambridgeCambridge, UK,Department of Experimental Psychology, University of CambridgeCambridge, UK
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774
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Dalley JW, Everitt BJ. Dopamine receptors in the learning, memory and drug reward circuitry. Semin Cell Dev Biol 2009; 20:403-10. [PMID: 19560045 DOI: 10.1016/j.semcdb.2009.01.002] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2008] [Revised: 01/08/2009] [Accepted: 01/09/2009] [Indexed: 11/22/2022]
Abstract
As primary targets of a variety of abused drugs G-protein-coupled dopamine receptors in the brain play an important role in mediating the various drug-induced alterations in neural and psychological processes thought to underlie the transition from voluntary drug use to habitual and progressively compulsive drug-taking. This review considers the functional involvement of the five major dopamine receptor subtypes in drug reinforcement and reward and discusses the development of addiction as a series of learning transitions from initial goal-directed behaviour to pathological stimulus-response habits in which drug-seeking behaviours are automatically elicited and maintained by cues and stimuli associated with drug rewards.
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Affiliation(s)
- Jeffrey W Dalley
- Behavioural and Clinical Neuroscience Institute, Department of Experimental Psychology, University of Cambridge, Cambridge, UK.
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775
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Anker JJ, Perry JL, Gliddon LA, Carroll ME. Impulsivity predicts the escalation of cocaine self-administration in rats. Pharmacol Biochem Behav 2009; 93:343-8. [PMID: 19490925 DOI: 10.1016/j.pbb.2009.05.013] [Citation(s) in RCA: 143] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2009] [Revised: 05/17/2009] [Accepted: 05/26/2009] [Indexed: 01/17/2023]
Abstract
Impulsivity, as measured by the delay-discounting task, predicts the acquisition of cocaine self-administration and reinstatement of cocaine seeking in rats. The purpose of this study was to extend these results to the escalation phase of drug self-administration. Female rats were initially screened for high (HiI) or low (LoI) impulsivity for food reinforcement using a delay-discounting procedure. They were then implanted with i.v. catheters and trained to lever press for cocaine infusions (0.8 mg/kg). Once cocaine intake stabilized, rats were allowed to self-administer cocaine (0.4 mg/kg) under a fixed-ratio 1 (FR 1) schedule during three, 2 h short-access sessions. Subsequently, performance was briefly assessed under a progressive ratio (PR) schedule for 3 doses of cocaine (0.2, 0.8, and 3.2 mg/kg). Following PR testing, the cocaine dose was then changed to 0.4 mg/kg. Session length was then extended to 6 h for 21 days (extended access), and 0.4 mg/kg cocaine was available under a FR 1 schedule. After the 21-day extended access phase, responses and infusions under the short access FR and PR dose-response conditions were reassessed. The results indicated that HiI rats escalated cocaine-reinforced responding during the extended access condition, but LoI rats did not. HiI rats also earned significantly more infusions than LoI rats under the post-escalation short access FR condition. However, HiI and LoI rats did not differ under the pre- and post-extended access PR conditions. This study suggests that individual differences in impulsivity predict escalation of cocaine self-administration in female rats, which may have implications in the prediction of binge-like patterns of cocaine intake in women.
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Affiliation(s)
- Justin J Anker
- Department of Psychiatry, University of Minnesota, Minneapolis, MN 55455, USA.
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776
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Economidou D, Pelloux Y, Robbins TW, Dalley JW, Everitt BJ. High impulsivity predicts relapse to cocaine-seeking after punishment-induced abstinence. Biol Psychiatry 2009; 65:851-6. [PMID: 19181308 DOI: 10.1016/j.biopsych.2008.12.008] [Citation(s) in RCA: 190] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2008] [Revised: 12/02/2008] [Accepted: 12/04/2008] [Indexed: 12/01/2022]
Abstract
BACKGROUND Relapse is a hallmark feature of cocaine addiction and a main challenge for treatment strategies. Human studies indicate a link between impulsivity and increased susceptibility to relapse. METHODS Rats were screened for high (HI) and low impulsivity (LI) on the 5-choice serial reaction time task. The HI and LI rats were trained to self-administer cocaine under a seeking-taking chained schedule: responses on the seeking lever resulted in presentation of the taking lever, responding upon which resulted in cocaine reinforcement. After the establishment of stable responding, an intermittent punishment schedule was introduced: completion of the seeking link resulted in the random presentation of either the taking lever or a mild footshock. This resulted in a progressive decrease in cocaine-seeking approaching abstinence. Relapse was assessed 7 days after punishment, during which responding on the seeking lever resulted in the presentation of the cocaine-associated stimuli (i.e., in the absence of cocaine or footshock). RESULTS The HI and LI animals significantly reinstated the cocaine-seeking response after a single phase of seeking punishment. However, after a second punishment phase only the HI rats reinitiated suppressed seeking responses and relapsed, an effect that was facilitated by prior extended cocaine access. In a preliminary study we found that the selective noradrenaline reuptake inhibitor, atomoxetine, a drug known to reduce impulsivity, prevented the reinstatement of cocaine-seeking. CONCLUSIONS Impulsivity pre-dating drug abuse increases the susceptibility to relapse after abstinence. Medications targeting impulsivity might have utility as treatment interventions for relapse prevention and the promotion of abstinence.
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Affiliation(s)
- Daina Economidou
- Behavioral and Clinical Neuroscience Institute, University of Cambridge, Downing St, Cambridge CB2 3EB, United Kingdom.
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777
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Schiffer WK, Liebling CNB, Reiszel C, Hooker JM, Brodie JD, Dewey SL. Cue-induced dopamine release predicts cocaine preference: positron emission tomography studies in freely moving rodents. J Neurosci 2009; 29:6176-85. [PMID: 19439595 PMCID: PMC6665516 DOI: 10.1523/jneurosci.5221-08.2009] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2008] [Revised: 02/20/2009] [Accepted: 03/05/2009] [Indexed: 11/21/2022] Open
Abstract
Positron emission tomography studies in drug-addicted patients have shown that exposure to drug-related cues increases striatal dopamine, which displaces binding of the D(2) ligand, [(11)C]-raclopride. However, it is not known if animals will also show cue-induced displacement of [(11)C]-raclopride binding. In this study, we use [(11)C]-raclopride imaging in awake rodents to capture cue-induced changes in dopamine release associated with the conditioned place preference model of drug craving. Ten animals were conditioned to receive cocaine in a contextually distinct environment from where they received saline. Following conditioning, each animal was tested for preference and then received two separate [(11)C]-raclopride scans. For each scan, animals were confined to the cocaine and/or the saline-paired environment for the first 25 min of uptake, after which they were anesthetized and scanned. [(11)C]-raclopride uptake in the saline-paired environment served as a within-animal control for uptake in the cocaine-paired environment. Cocaine produced a significant place preference (p = 0.004) and exposure to the cocaine-paired environment decreased [(11)C]-raclopride binding relative to the saline-paired environment in both the dorsal (20%; p < 0.002) and ventral striatum (22%; p < 0.05). The change in [(11)C]-raclopride binding correlated with preference in the ventral striatum (R(2) = -0.87; p = 0.003). In this region, animals who showed little or no preference exhibited little or no change in [(11)C]-raclopride binding in the cocaine-paired environment. This noninvasive procedure of monitoring neurochemical events in freely moving, behaving animals advances preclinical molecular imaging by interrogating the degree to which animal models reflect the human condition on multiple dimensions, both biological and behavioral.
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Affiliation(s)
- Wynne K Schiffer
- Medical Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
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778
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Yacubian J, Büchel C. The genetic basis of individual differences in reward processing and the link to addictive behavior and social cognition. Neuroscience 2009; 164:55-71. [PMID: 19446009 DOI: 10.1016/j.neuroscience.2009.05.015] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2008] [Revised: 04/20/2009] [Accepted: 05/06/2009] [Indexed: 11/17/2022]
Abstract
Dopaminergic neurotransmission is widely recognized to be critical to the neurobiology of reward, motivation and addiction. Interestingly, social interactions and related behavior also activate the same neuronal system. Consequently, genetic variations of dopamine neurotransmission are thought influence reward processing that in turn may affect distinctive social behavior and susceptibility to addiction. This review focuses on advances made to date in an effort to link genetic individual variations and reward processing as a possible basis for addictive behaviors.
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Affiliation(s)
- J Yacubian
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
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779
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Dopamine release in dissociable striatal subregions predicts the different effects of oral methylphenidate on reversal learning and spatial working memory. J Neurosci 2009; 29:4690-6. [PMID: 19369539 DOI: 10.1523/jneurosci.3266-08.2009] [Citation(s) in RCA: 172] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Previous data suggest that methylphenidate can have variable effects on different cognitive tasks both within and between individuals. This is thought to be underpinned by inverted U-shaped relationships between cognitive performance and dopaminergic activity in relatively separate fronto-striatal circuits and reflected by individual differences in trait impulsivity. Direct evidence for this is currently lacking. In this study, we demonstrate for the first time that therapeutic doses of oral methylphenidate administered to young healthy subjects result in different sized changes in D(2)/D(3) receptor availability in different regions of the human striatum and that the change in receptor availability within an individual subregion predicts cognitive performance on a particular task. Methylphenidate produced significantly different effects on reversal learning and spatial working memory tasks within individuals. Performance on the reversal learning task was predicted by the drug-induced change in D(2)/D(3) receptor availability in postcommissural caudate, measured using [(11)C]-raclopride radioligand PET imaging, whereas performance on the spatial working memory task was predicted by changes in receptor availability in the ventral striatum. Reversal learning performance was also predicted by subjects' trait impulsivity, such that the most impulsive individuals benefited more from methylphenidate, consistent with this drug's beneficial effects on cognition in attention deficit hyperactivity disorder.
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780
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Insights into the neural basis of response inhibition from cognitive and clinical neuroscience. Neurosci Biobehav Rev 2009; 33:631-46. [PMID: 18835296 DOI: 10.1016/j.neubiorev.2008.08.016] [Citation(s) in RCA: 574] [Impact Index Per Article: 38.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2008] [Revised: 07/31/2008] [Accepted: 08/17/2008] [Indexed: 11/20/2022]
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781
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Santangelo G, Vitale C, Trojano L, Verde F, Grossi D, Barone P. Cognitive dysfunctions and pathological gambling in patients with Parkinson's disease. Mov Disord 2009; 24:899-905. [DOI: 10.1002/mds.22472] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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782
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Oberlin BG, Grahame NJ. High-alcohol preferring mice are more impulsive than low-alcohol preferring mice as measured in the delay discounting task. Alcohol Clin Exp Res 2009; 33:1294-303. [PMID: 19389183 DOI: 10.1111/j.1530-0277.2009.00955.x] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Repeated studies have shown that high impulsivity, when defined as the tendency to choose small immediate rewards over larger delayed rewards, is more prevalent in drug addicts and alcoholics when compared with nonaddicts. Assessing whether impulsivity precedes and potentially causes addiction disorders is difficult in humans because they all share a history of drug use. In this study, we address this question by testing alcohol-naïve mice from lines showing heritable differences in alcohol intake. METHODS Replicated selected lines of outbred high-alcohol preferring (HAP) mice were compared to a low-alcohol preferring (LAP) line as well as the low-drinking progenitor line (HS/Ibg) on an adjusting amount delay discounting (DD) task. The DD task employs 2 levers to present subjects with a choice between a small, immediate and a large, delayed saccharin reward. By adjusting the quantity of the immediate reward up and down based on choice behavior, the task allows an estimate of how the subjective value of the delayed reinforcer decreases as delays increase. Latency to respond was also measured for each trial. RESULTS Both HAP2 and HAP1 lines of mice were more impulsive than the LAP2 and HS/Ibg lines, respectively. Hyperbolic curve-fitting confirmed steeper discounting in the high-alcohol drinking lines. In addition, the high-alcohol drinking lines demonstrated greater within-session increases in reaction times relative to the low-alcohol drinking lines. No other differences (consumption of saccharin, total trials completed) consistently mapped onto genetic differences in alcohol drinking. CONCLUSIONS Alcohol-naïve outbred mice selected for high-alcohol drinking were more impulsive with saccharin reinforcers than low-alcohol drinkers. These data are consistent with results seen using inbred strain descendents of high-alcohol drinking and low-alcohol drinking rat lines, and suggest that impulsivity is a heritable difference that precedes alcoholism.
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Affiliation(s)
- B G Oberlin
- Department of Psychology, Indiana University Purdue University at Indianapolis, Indianapolis, Indiana, USA
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783
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Abstract
In humans, presence of an A1 allele of the DRD2/ANKK1-TaqIa polymorphism is associated with reduced expression of dopamine (DA) D(2) receptors in the striatum. Recently, it was observed that carriers of the A1 allele (A1+ subjects) showed impaired learning from negative feedback in a reinforcement learning task. Here, using functional MRI (fMRI), we investigated carriers and noncarriers of the A1 allele while they performed a probabilistic reversal learning task. A1+ subjects showed subtle deficits in reversal learning. In particular, these deficits consisted of an impairment in sustaining the newly rewarded response after a reversal and in a generally decreased tendency to stick with a rewarded response. Both genetic groups showed increased fMRI signal in response to negative feedback in the rostral cingulate zone (RCZ) and anterior insula. Negative feedback that incurred a change in behavior additionally engaged the ventral striatum and a region of the midbrain consistent with the location of dopaminergic cell groups. The response of the RCZ to negative feedback increased as a function of preceding negative feedback. However, this graded response was not observed in the A1+ group. Furthermore, the A1+ group also showed diminished recruitment of the right ventral striatum and the right lateral orbitofrontal cortex (lOFC) during reversals. Together, these results suggest that a genetically driven reduction in DA D(2) receptors leads to deficient feedback integration in RCZ. This, in turn, was accompanied by impaired recruitment of the ventral striatum and the right lOFC during reversals, which might explain the behavioral differences between the genetic groups.
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784
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Orio L, Edwards S, George O, Parsons LH, Koob GF. A role for the endocannabinoid system in the increased motivation for cocaine in extended-access conditions. J Neurosci 2009; 29:4846-57. [PMID: 19369553 PMCID: PMC2688678 DOI: 10.1523/jneurosci.0563-09.2009] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2009] [Revised: 03/09/2009] [Accepted: 03/11/2009] [Indexed: 11/21/2022] Open
Abstract
Extended access to cocaine produces an increase in cocaine self-administration in rats that mimics aspects of compulsive drug intake in human addicts. Although emerging evidence implicates the endogenous cannabinoid system in aspects of opioid and ethanol addiction, a role of the endocannabinoid system in cocaine addiction remains widely inconclusive. Here, we investigate the effects of systemic and intra-accumbal administration of the CB1 antagonist SR141716A (Rimonabant) on cocaine self-administration (0.5 mg/kg/infusion) under a progressive ratio (PR) schedule in rats with extended [long access (LgA); 6 h/d] or limited [short access (ShA); 1 h/d] access to cocaine. LgA rats, but not ShA rats, showed an increase in cocaine intake as previously reported, and responding for cocaine by LgA rats was higher than in ShA rats under a PR schedule. Systemic SR141716A induced a dramatic dose-dependent decrease in the breakpoint for cocaine by LgA rats, whereas only the highest dose of the antagonist had a significant effect in the ShA group. Anandamide levels in the nucleus accumbens (NAc) shell were decreased in ShA rats but unchanged in LgA rats during cocaine self-administration. Both phosphorylated and total CB1 receptor protein expression were upregulated in LgA rats in the NAc and the amygdala compared with ShA and drug-naive rats, 24 h after last cocaine session. Finally, intra-NAc infusions of SR141716A reduced cocaine breakpoints selectively in LgA animals. These results suggest that neuroadaptations in the endogenous cannabinoid system may be part of the neuroplasticity associated with the development of cocaine addiction.
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Affiliation(s)
- Laura Orio
- Committee on Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California 92037, USA.
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785
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Steeves TDL, Miyasaki J, Zurowski M, Lang AE, Pellecchia G, Van Eimeren T, Rusjan P, Houle S, Strafella AP. Increased striatal dopamine release in Parkinsonian patients with pathological gambling: a [11C] raclopride PET study. Brain 2009; 132:1376-85. [PMID: 19346328 DOI: 10.1093/brain/awp054] [Citation(s) in RCA: 347] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Pathological gambling is an impulse control disorder reported in association with dopamine agonists used to treat Parkinson's disease. Although impulse control disorders are conceptualized as lying within the spectrum of addictions, little neurobiological evidence exists to support this belief. Functional imaging studies have consistently demonstrated abnormalities of dopaminergic function in patients with drug addictions, but to date no study has specifically evaluated dopaminergic function in Parkinson's disease patients with impulse control disorders. We describe results of a [(11)C] raclopride positron emission tomography (PET) study comparing dopaminergic function during gambling in Parkinson's disease patients, with and without pathological gambling, following dopamine agonists. Patients with pathological gambling demonstrated greater decreases in binding potential in the ventral striatum during gambling (13.9%) than control patients (8.1%), likely reflecting greater dopaminergic release. Ventral striatal bindings at baseline during control task were also lower in patients with pathological gambling. Although prior imaging studies suggest that abnormality in dopaminergic binding and dopamine release may be markers of vulnerability to addiction, this study presents the first evidence of these phenomena in pathological gambling. The emergence of pathological gambling in a number of Parkinson's disease patients may provide a model into the pathophysiology of this disorder.
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Affiliation(s)
- T D L Steeves
- Movement Disorders Centre, Toronto Western Hospital, UHN, Ontario, Canada
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786
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Leri F, Zhou Y, Goddard B, Levy A, Jacklin D, Kreek MJ. Steady-state methadone blocks cocaine seeking and cocaine-induced gene expression alterations in the rat brain. Eur Neuropsychopharmacol 2009; 19:238-49. [PMID: 18990547 PMCID: PMC2900837 DOI: 10.1016/j.euroneuro.2008.09.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2008] [Revised: 08/22/2008] [Accepted: 09/30/2008] [Indexed: 11/26/2022]
Abstract
To elucidate the effects of steady-state methadone exposure on responding to cocaine conditioned stimuli and on cocaine-induced alterations in central opioid, hypocretin/orexin, and D2 receptor systems, male Sprague-Dawley rats received intravenous infusions of 1 mg/kg/inf cocaine paired with an audiovisual stimulus over three days of conditioning. Then, mini pumps releasing vehicle or 30 mg/kg/day methadone were implanted (SC), and lever pressing for the stimulus was assessed in the absence of cocaine and after a cocaine prime (20 mg/kg, IP). It was found that rats treated with vehicle, but not methadone, responded for the cocaine conditioned stimulus and displayed elevated mu-opioid receptor mRNA expression in the nucleus accumbens core and basolateral amygdala, reduced hypocretin/orexin mRNA in the lateral hypothalamus, and reduced D2 receptor mRNA in the caudate-putamen. This is the first demonstration that steady-state methadone administered after cocaine exposure blocks cocaine-induced behavioral and neural adaptations.
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MESH Headings
- Acoustic Stimulation/methods
- Analgesics, Opioid/administration & dosage
- Analysis of Variance
- Animals
- Behavior, Animal/drug effects
- Brain/drug effects
- Cocaine/pharmacology
- Cocaine-Related Disorders/drug therapy
- Cocaine-Related Disorders/metabolism
- Conditioning, Classical/drug effects
- Conditioning, Operant/drug effects
- Dopamine Uptake Inhibitors/pharmacology
- Drug Administration Schedule
- Drug Delivery Systems/methods
- Dynorphins/genetics
- Dynorphins/metabolism
- Gene Expression Regulation/drug effects
- Intracellular Signaling Peptides and Proteins/genetics
- Intracellular Signaling Peptides and Proteins/metabolism
- Locomotion/drug effects
- Male
- Methadone/administration & dosage
- Neuropeptides/genetics
- Neuropeptides/metabolism
- Orexins
- Photic Stimulation/methods
- RNA, Messenger/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptors, Dopamine D2/genetics
- Receptors, Dopamine D2/metabolism
- Receptors, Opioid, mu/genetics
- Receptors, Opioid, mu/metabolism
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Affiliation(s)
- Francesco Leri
- Department of Psychology, University of Guelph, Guelph, Canada.
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787
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Eagle DM, Lehmann O, Theobald DEH, Pena Y, Zakaria R, Ghosh R, Dalley JW, Robbins TW. Serotonin depletion impairs waiting but not stop-signal reaction time in rats: implications for theories of the role of 5-HT in behavioral inhibition. Neuropsychopharmacology 2009; 34:1311-21. [PMID: 19005464 DOI: 10.1038/npp.2008.202] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Central serotonin (5-HT) function is thought to be a critical component of behavioral inhibition and impulse control. However, in recent clinical studies, 5-HT manipulations failed to affect stop-signal reaction time (SSRT), which is a fundamental process in behavioral inhibition. We investigated the effect of central 5-HT depletion (intracerebroventricular 5,7-dihydroxytryptamine) in rats on two aspects of behavioral inhibition, SSRT and 'waiting', using the stop-signal task. 5-HT depletion had no effects on SSRT or any other primary measure on the stop-signal task. However, within the same task, there was a deficit in 'waiting' in 5-HT-depleted rats when they were required to withhold from responding in the terminal element of the stop-signal task for an extended period. D-Amphetamine had dose-dependent, but not 5-HT-dependent effects on SSRT. Conversely, the dose that tended to improve, or decrease, SSRT (0.3 mg/kg) impaired the ability to wait, again independently of 5-HT manipulation. These findings suggest that SSRT and 'waiting' are distinct measures of behavioral inhibition, and show that 5-HT is critical for some forms of behavioral inhibition but not others. This has significant implications for the treatment of conditions such as attention deficit and hyperactivity disorder, substance abuse, and affective disorders, in which inhibitory and impulse-control deficits are common.
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Affiliation(s)
- Dawn M Eagle
- Department of Experimental Psychology and the Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK.
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788
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Dagher A, Robbins TW. Personality, addiction, dopamine: insights from Parkinson's disease. Neuron 2009; 61:502-10. [PMID: 19249271 DOI: 10.1016/j.neuron.2009.01.031] [Citation(s) in RCA: 252] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2007] [Revised: 01/07/2009] [Accepted: 01/08/2009] [Indexed: 11/18/2022]
Abstract
In rare instances, patients with Parkinson's disease (PD) may become addicted to their own medication or develop behavioral addictions such as pathological gambling. This is surprising because PD patients typically have a very low incidence of drug abuse and display a personality type that is the polar opposite of the addictive personality. These rare addictive syndromes, which appear to result from excessive dopaminergic medication use, illustrate the link between dopamine, personality, and addiction. We describe the clinical phenomena and attempt to relate them to current models of learning and addiction. We conclude that persistently elevated dopaminergic stimulation promotes the development and maintenance of addictive behaviors.
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Affiliation(s)
- Alain Dagher
- Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, QC H3A 2B4, Canada.
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789
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Phillips GD, Hitchcott PK. Blockade of the acquisition, but not expression, of associative learning by pre-session intra-amygdala R(+) 7-OH-DPAT. Psychopharmacology (Berl) 2009; 203:161-73. [PMID: 18949458 DOI: 10.1007/s00213-008-1382-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2008] [Accepted: 10/13/2008] [Indexed: 12/17/2022]
Abstract
RATIONALE Two issues were addressed regarding the effects of amygdala dopamine manipulations on associative learning: first, an apparent contradiction between the effects of post- vs. pre-session dopaminergic manipulations and second, the ability of dopaminergic infusions to affect association formation vs. its expression following extended training. OBJECTIVES The ability of pre-session infusions of a dopamine receptor agonist (R(+) 7-OH-DPAT) to inhibit acquisition of a conditioned approach response was examined and compared with the same manipulation following overtraining. Further experiments extended these findings. MATERIALS AND METHODS Experiment 1 infused pre-session intra-amygdala R(+) 7-OH-DPAT (0, 0.1, 1 nmol) during conditioned approach acquisition. Experiment 2 applied pre-session intra-amygdala R(+) 7-OH-DPAT (0, 0.01, 0.1, 1 nmol) during expression of the same response, once well learned. Experiment 3 required the inhibition of a conditioned approach response following unconditioned stimulus (US) removal. Experiment 4 examined the ability of animals with prior drug experience to acquire a conditioned response to a novel stimulus. RESULTS Experiments 1-3 showed that pre-session amygdala R(+) 7-OH-DPAT impaired acquisition of either excitatory or inhibitory conditioned responding, but was ineffective following overtraining. Drug-induced impairments in acquisition of a specific conditioned stimulus (CS)-US relationship continued well beyond the cessation of drug treatment, but were found not to transfer to an alternate CS in Experiment 4. CONCLUSIONS Pre-session dopamine receptor activation within the amygdala may impair the acquisition, but not expression, of CS-US associations. Enhanced learning reported earlier following post-session dopamine receptor activation may occur indirectly through reduced interference with the consolidation of recent learning.
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Affiliation(s)
- Gavin D Phillips
- Department of Psychology, University of York, Heslington, York, YO10 5DD, UK.
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790
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Leeman RF, Grant JE, Potenza MN. Behavioral and neurological foundations for the moral and legal implications of intoxication, addictive behaviors and disinhibition. BEHAVIORAL SCIENCES & THE LAW 2009; 27:237-259. [PMID: 19241397 PMCID: PMC2748412 DOI: 10.1002/bsl.855] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Disinhibition and addictive behaviors are related and carry moral implications. Both typically involve diminished consideration of negative consequences, which may result in harm to oneself or others. Disinhibition may occur on state and trait levels, and addictive substances may elicit disinhibitory states, particularly when intoxication is reached. Data suggest that trait disinhibition and addictions may be conceptualized as involving misdirected motivation with underlying biological bases including genetic factors, alterations in neurotransmitter systems and differences in regional brain function. The influences of intoxication on the brain share similarities with cognitive impairments in individuals with chronic substance abuse and those with trait disinhibition related to frontal lobe injuries. These findings raise questions about volitional impairment and morality. Although impaired volition related to disinhibition and addictive behaviors has been studied from multiple perspectives, additional research is needed to further characterize mechanisms of impairment. Such findings may have important implications in multiple legal and psychiatric domains.
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Affiliation(s)
- Robert F Leeman
- Yale University School of Medicine, Substance Abuse Center, CMHC, 34 Park Street, Room S200, New Haven, CT 06519, USA.
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791
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Williams KW, Scott MM, Elmquist JK. From observation to experimentation: leptin action in the mediobasal hypothalamus. Am J Clin Nutr 2009; 89:985S-990S. [PMID: 19176744 PMCID: PMC2667659 DOI: 10.3945/ajcn.2008.26788d] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The burgeoning obesity epidemic has fueled the drive to describe, mechanistically, metabolic homeostasis. From the early theories implicating glucose as a principal modulator grew an understanding of a complex array of metabolic signals, sensed by peripheral organs along with specific locations within the central nervous system (CNS). The discovery that leptin, an adipose-derived hormone, acts within the mediobasal hypothalamus to control food intake and energy expenditure ushered in a decade of research that went on to describe not only the specific nuclei and cell type, such as proopiomelanocortin neurons of the arcuate nucleus, that respond to leptin but also the signaling cascades that mediated its effects. This review thus highlights the sites and mechanisms of action of leptin, both in the hypothalamus and in extrahypothalamic sites within the CNS, and shows our current knowledge and direction of future research aimed at understanding the multifunctional role of leptin in maintaining metabolic homeostasis.
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Affiliation(s)
- Kevin W Williams
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 85390-905, USA
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792
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Riddick NV, Czoty PW, Gage HD, Kaplan JR, Nader SH, Icenhower M, Pierre PJ, Bennett A, Garg PK, Garg S, Nader MA. Behavioral and neurobiological characteristics influencing social hierarchy formation in female cynomolgus monkeys. Neuroscience 2009; 158:1257-65. [PMID: 19059311 PMCID: PMC3170522 DOI: 10.1016/j.neuroscience.2008.11.016] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2008] [Revised: 11/10/2008] [Accepted: 11/11/2008] [Indexed: 11/20/2022]
Abstract
Socially housed monkeys have been used as a model to study human diseases. The present study examined behavioral, physiological and neurochemical measures as predictors of social rank in 16 experimentally naïve, individually housed female cynomolgus monkeys (Macaca fascicularis). The two behavioral measures examined were novel object reactivity (NOR), as determined by latency to touch an opaque acrylic box placed in the home cage, and locomotor activity assessed in a novel open-field apparatus. Serum cortisol concentrations were evaluated three times per week for four consecutive weeks, and stress reactivity was assessed on one occasion by evaluating the cortisol response to adrenocorticotropic hormone (ACTH) following dexamethasone suppression. Measures of serotonin (5-HT) function included whole blood 5-HT (WBS) concentrations, cerebrospinal fluid (CSF) concentrations of the 5-HT metabolite 5-hydroxyindoleacetic acid (5-HIAA) and brain 5-HT transporter (SERT) availability obtained using positron emission tomography (PET). After baseline measures were obtained, monkeys were assigned to four social groups of four monkeys per group. The two measures that correlated with eventual social rank were CSF 5-HIAA concentrations, which were significantly higher in the animals who eventually became subordinate, and latency to touch the novel object, which was significantly lower in eventual subordinate monkeys. Measures of 5-HT function did not change as a consequence of social rank. These data suggest that levels of central 5-HIAA and measures of novel object reactivity may be trait markers that influence eventual social rank in female macaques.
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Affiliation(s)
- N V Riddick
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1083, USA
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793
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Calaminus C, Hauber W. Modulation of Behavior by Expected Reward Magnitude Depends on Dopamine in the Dorsomedial Striatum. Neurotox Res 2009; 15:97-110. [DOI: 10.1007/s12640-009-9009-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2008] [Revised: 01/20/2009] [Accepted: 01/26/2009] [Indexed: 11/25/2022]
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794
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Mu and delta opioid receptors oppositely regulate motor impulsivity in the signaled nose poke task. PLoS One 2009; 4:e4410. [PMID: 19198656 PMCID: PMC2635474 DOI: 10.1371/journal.pone.0004410] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2008] [Accepted: 12/24/2008] [Indexed: 12/17/2022] Open
Abstract
Impulsivity is a primary feature of many psychiatric disorders, most notably attention deficit hyperactivity disorder and drug addiction. Impulsivity includes a number of processes such as the inability to delay gratification, the inability to withhold a motor response, or acting before all of the relevant information is available. These processes are mediated by neural systems that include dopamine, serotonin, norepinephrine, glutamate and cannabinoids. We examine, for the first time, the role of opioid systems in impulsivity by testing whether inactivation of the mu- (Oprm1) or delta- (Oprd1) opioid receptor gene alters motor impulsivity in mice. Wild-type and knockout mice were examined on either a pure C57BL6/J (BL6) or a hybrid 50% C57Bl/6J–50% 129Sv/pas (HYB) background. Mice were trained to respond for sucrose in a signaled nose poke task that provides independent measures of associative learning (responses to the reward-paired cue) and motor impulsivity (premature responses). Oprm1 knockout mice displayed a remarkable decrease in motor impulsivity. This was observed on the two genetic backgrounds and did not result from impaired associative learning, as responses to the cue signaling reward did not differ across genotypes. Furthermore, mutant mice were insensitive to the effects of ethanol, which increased disinhibition and decreased conditioned responding in wild-type mice. In sharp contrast, mice lacking the Oprd1 gene were more impulsive than controls. Again, mutant animals showed no deficit in associative learning. Ethanol completely disrupted performance in these animals. Together, our results suggest that mu-opioid receptors enhance, whereas delta-opioid receptors inhibit, motor impulsivity. This reveals an unanticipated contribution of endogenous opioid receptor activity to disinhibition. In a broader context, these data suggest that alterations in mu- or delta-opioid receptor function may contribute to impulse control disorders.
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795
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Madden GJ, Smith NG, Brewer AT, Pinkston JW, Johnson PS. Steady-state assessment of impulsive choice in Lewis and Fischer 344 rats: between-condition delay manipulations. J Exp Anal Behav 2009; 90:333-44. [PMID: 19070340 DOI: 10.1901/jeab.2008.90-333] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Previous research has shown that Lewis rats make more impulsive choices than Fischer 344 rats. Such strain-related differences in choice are important as they may provide an avenue for exploring genetic and neurochemical contributions to impulsive choice. The present systematic replication was designed to determine if these findings could be reproduced using a procedure less susceptible to within- or between-session carry-over effects that may have affected previous findings. Specifically, delays to the larger-later food reinforcer were manipulated between conditions following steady-state assessments of choice, and the order of delays across conditions was mixed. The results confirmed previous findings that Lewis rats made significantly more impulsive choices than Fischer 344 rats. Fischer 344 rats' preference for the larger-later reinforcer, on the other hand, was less extreme than reported in prior research, which may be due to carry-over effects inherent to the commonly used technique of systematically increasing delays within session. Previously reported across-strain motor differences were reproduced as Lewis rats had shorter latencies than Fischer 344 rats, although these latencies were not correlated with impulsive choice. Parallels between reduced dopamine function in Lewis rats and clinical reports of impulse-control disorders following treatment of Parkinson patients with selective D2/D3 dopamine agonists are discussed.
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Affiliation(s)
- Gregory J Madden
- Department of Applied Behavioral Science, University of Kansas, 1000 Sunnyside Ave., Lawrence, KS 66045, USA.
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796
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Interaction between DRD2 C957T polymorphism and an acute psychosocial stressor on reward-related behavioral impulsivity. Behav Genet 2009; 39:285-95. [PMID: 19148742 DOI: 10.1007/s10519-008-9255-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2008] [Accepted: 12/23/2008] [Indexed: 01/15/2023]
Abstract
The dopamine D2 receptor (DRD2) C957T polymorphism CC genotype is associated with decreased striatal binding of DRD2 and executive function and working memory impairments in healthy adults. We investigated the relationships between C957T and acute stress with behavioral phenotypes of impulsivity in 72 young adults randomly allocated to either an acute psychosocial stress or relaxation induction condition. Homozygotes for 957C showed increased reward responsiveness after stress induction. They were also quicker when making immediate choices on the delay discounting task when stressed, compared with homozygotes who were not stressed. No effects were found for response inhibition, a dimension of impulsivity not related to extrinsic rewards. These data suggest that C957T is associated with a reward-related impulsivity endophenotype in response to acute psychosocial stress. Future studies should examine whether the greater sensitivity of 957C homozygotes to the effects of stress is mediated through dopamine release.
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797
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Robinson E, Eagle D, Economidou D, Theobald D, Mar A, Murphy E, Robbins T, Dalley J. Behavioural characterisation of high impulsivity on the 5-choice serial reaction time task: Specific deficits in ‘waiting’ versus ‘stopping’. Behav Brain Res 2009; 196:310-6. [DOI: 10.1016/j.bbr.2008.09.021] [Citation(s) in RCA: 144] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2008] [Revised: 09/12/2008] [Accepted: 09/22/2008] [Indexed: 11/25/2022]
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798
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Forbes EE, Brown SM, Kimak M, Ferrell RE, Manuck SB, Hariri AR. Genetic variation in components of dopamine neurotransmission impacts ventral striatal reactivity associated with impulsivity. Mol Psychiatry 2009; 14:60-70. [PMID: 17893706 PMCID: PMC2668513 DOI: 10.1038/sj.mp.4002086] [Citation(s) in RCA: 345] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Individual differences in traits such as impulsivity involve high reward sensitivity and are associated with risk for substance use disorders. The ventral striatum (VS) has been widely implicated in reward processing, and individual differences in its function are linked to these disorders. Dopamine (DA) plays a critical role in reward processing and is a potent neuromodulator of VS reactivity. Moreover, altered DA signaling has been associated with normal and pathological reward-related behaviors. Functional polymorphisms in DA-related genes represent an important source of variability in DA function that may subsequently impact VS reactivity and associated reward-related behaviors. Using an imaging genetics approach, we examined the modulatory effects of common, putatively functional DA-related polymorphisms on reward-related VS reactivity associated with self-reported impulsivity. Genetic variants associated with relatively increased striatal DA release (DRD2 -141C deletion) and availability (DAT1 9-repeat), as well as diminished inhibitory postsynaptic DA effects (DRD2 -141C deletion and DRD4 7-repeat), predicted 9-12% of the interindividual variability in reward-related VS reactivity. In contrast, genetic variation directly affecting DA signaling only in the prefrontal cortex (COMT Val158Met) was not associated with variability in VS reactivity. Our results highlight an important role for genetic polymorphisms affecting striatal DA neurotransmission in mediating interindividual differences in reward-related VS reactivity. They further suggest that altered VS reactivity may represent a key neurobiological pathway through which these polymorphisms contribute to variability in behavioral impulsivity and related risk for substance use disorders.
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Affiliation(s)
- EE Forbes
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Psychology, University of Pittsburgh, Pittsburgh, PA, USA
| | - SM Brown
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
| | - M Kimak
- Department of Human Genetics, University of Pittsburgh, Pittsburgh, PA, USA
| | - RE Ferrell
- Department of Human Genetics, University of Pittsburgh, Pittsburgh, PA, USA
| | - SB Manuck
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Psychology, University of Pittsburgh, Pittsburgh, PA, USA
| | - AR Hariri
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Psychology, University of Pittsburgh, Pittsburgh, PA, USA
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799
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Significant association of ANKK1 and detection of a functional polymorphism with nicotine dependence in an African-American sample. Neuropsychopharmacology 2009; 34:319-30. [PMID: 18354387 DOI: 10.1038/npp.2008.37] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The dopaminergic system in the brain plays a critical role in nicotine addiction. Genetic variants in the dopaminergic system, including those in dopamine receptor genes, represent plausible candidates for the genetic study of nicotine dependence (ND). We investigated various polymorphisms in the dopamine D(2) receptor gene (DRD2) and its neighboring ankyrin repeats and kinase domain containing 1 gene (ANKK1) to determine whether they were associated with ND. We examined 16 single nucleotide polymorphisms (SNPs) at DRD2 and 7 SNPs at ANKK1 in our Mid-South Tobacco Family cohort, which consisted of 2037 participants representing two distinct American populations. Several SNPs (rs7131056, rs4274224, rs4648318, and rs6278) in DRD2, along with the Taq IA polymorphism (rs1800497) in ANKK1, revealed initial significant associations with ND in European Americans, but not after correction for multiple testing, indicating a weak association of DRD2 with ND. In contrast, associations for ANKK1 with ND in the African-American and pooled samples, specifically for SNP rs2734849, remained significant after correction. With a non-synonymous G to A transition, rs2734849 produces an amino-acid change (arginine to histidine) in C-terminal ankyrin repeat domain of ANKK1. Using the luciferase reporter assay, we further demonstrated that the variant alters expression level of NF-kappaB-regulated genes. Since DRD2 expression is regulated by transcription factor NF-kappaB, we suspect that rs2734849 may indirectly affect dopamine D(2) receptor density. We conclude that ANKK1 is associated with ND and polymorphism rs2734849 in ANKK1 represents a functional causative variant for ND in African-American smokers.
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800
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Effects of atomoxetine and methylphenidate on performance of a lateralized reaction time task in rats. Psychopharmacology (Berl) 2009; 202:497-504. [PMID: 18535818 DOI: 10.1007/s00213-008-1181-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2007] [Accepted: 04/16/2008] [Indexed: 10/22/2022]
Abstract
RATIONALE The ability to detect unpredictable cues can involve stimulus-elicited orienting of attention (bottom-up processing); however, in many settings, target onset is partially predictable, meaning that subjects can benefit from the rule-guided, endogenous control of attention (top-down processing). Noradrenaline has been implicated in attention per se, but it is not clear whether it differentially participates in these two dimensions of attentional function. OBJECTIVES We sought to examine the effects of selective or nonselective inhibitors of noradrenaline reuptake on different modes of attentional performance in rats. MATERIALS AND METHODS Adult male Long-Evans rats were trained to perform a lateralized reaction time task where a variable-duration preparatory period preceded delivery of a visual target stimulus. Atomoxetine (1 mg/kg, i.p.) or methylphenidate (0.32 mg/kg, i.p.) were administered before sessions in which the preparatory period was systematically varied. RESULTS When the preparatory time was brief (0.2 s), response times were significantly longer than when the preparatory time was long (1.0 s), suggesting that rats were able to orient their attention before target onset when the longer period was imposed. Atomoxetine differentially modulated performance in these two conditions, improving response accuracy when a long preparatory period was imposed but impairing accuracy when the preparatory time was made brief. Methylphenidate did not differentially affect responding under the two conditions. CONCLUSIONS These data suggest that selective inhibition of the noradrenaline transporter may specifically benefit attentional performance of tasks that permit the controlled recruitment of attention, rather than during tests of pure stimulus-driven attention.
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