151
|
Higuera-Matas A, Montoya GL, Coria SM, Miguéns M, García-Lecumberri C, Ambrosio E. Differential gene expression in the nucleus accumbens and frontal cortex of lewis and Fischer 344 rats relevant to drug addiction. Curr Neuropharmacol 2011; 9:143-50. [PMID: 21886580 PMCID: PMC3137170 DOI: 10.2174/157015911795017290] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2009] [Revised: 04/17/2010] [Accepted: 05/26/2010] [Indexed: 11/22/2022] Open
Abstract
Drug addiction results from the interplay between social and biological factors. Among these, genetic variables play a major role. The use of genetically related inbred rat strains that differ in their preference for drugs of abuse is one approach of great importance to explore genetic determinants. Lewis and Fischer 344 rats have been extensively studied and it has been shown that the Lewis strain is especially vulnerable to the addictive properties of several drugs when compared with the Fischer 344 strain. Here, we have used microarrays to analyze gene expression profiles in the frontal cortex and nucleus accumbens of Lewis and Fischer 344 rats. Our results show that only a very limited group of genes were differentially expressed in Lewis rats when compared with the Fischer 344 strain. The genes that were induced in the Lewis strain were related to oxygen transport, neurotransmitter processing and fatty acid metabolism. On the contrary genes that were repressed in Lewis rats were involved in physiological functions such as drug and proton transport, oligodendrocyte survival and lipid catabolism. These data might be useful for the identification of genes which could be potential markers of the vulnerability to the addictive properties of drugs of abuse.
Collapse
Affiliation(s)
- A Higuera-Matas
- Departamento de Psicobiología, Facultad de Psicología, UNED, Madrid, Spain
| | | | | | | | | | | |
Collapse
|
152
|
Vansickel AR, Stoops WW, Glaser PEA, Poole MM, Rush CR. Methylphenidate increases cigarette smoking in participants with ADHD. Psychopharmacology (Berl) 2011; 218:381-90. [PMID: 21590284 PMCID: PMC3189423 DOI: 10.1007/s00213-011-2328-y] [Citation(s) in RCA: 25] [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: 03/15/2011] [Accepted: 04/22/2011] [Indexed: 01/09/2023]
Abstract
RATIONALE Methylphenidate (Ritalin®) is commonly prescribed for behavioral problems associated with attention deficit/hyperactivity disorder (ADHD). The results of previous studies suggest that methylphenidate increases cigarette smoking in participants without psychiatric diagnoses. Whether methylphenidate increases cigarette smoking in participants diagnosed with ADHD is unknown. OBJECTIVE In this within-subjects, repeated measures experiment, the acute effects of a range of doses of methylphenidate (10, 20, and 40 mg) and placebo were assessed in nine cigarette smokers who were not attempting to quit and met diagnostic criteria for ADHD but no other Axis I psychiatric disorders other than nicotine dependence. METHODS Each dose of methylphenidate was tested once while placebo was tested twice. One hour after ingesting drug, participants were allowed to smoke ad libitum for 4 h. Measures of smoking included total cigarettes smoked, total puffs, and carbon monoxide levels. Snacks and decaffeinated drinks were available ad libitum; caloric intake during the 4-h smoking session was calculated. RESULTS Methylphenidate increased the total number of cigarettes smoked, total number of puffs, and carbon monoxide levels. Methylphenidate decreased the number of food items consumed and caloric intake. CONCLUSIONS The results of this experiment suggest that acutely administered methylphenidate increases cigarette smoking in participants with ADHD, which is concordant with findings from previous studies that tested healthy young adults. These data indicate that clinicians may need to consider non-stimulant options or counsel their patients before starting methylphenidate when managing ADHD-diagnosed individuals who smoke.
Collapse
Affiliation(s)
- Andrea R. Vansickel
- Department of Behavioral Science, College of Medicine, University of Kentucky, Lexington, KY 40536, USA
- Department of Psychology, College of Arts and Science, University of Kentucky Lexington, KY 40536, USA
| | - William W. Stoops
- Department of Behavioral Science, College of Medicine, University of Kentucky, Lexington, KY 40536, USA
- Department of Psychology, College of Arts and Science, University of Kentucky Lexington, KY 40536, USA
| | - Paul E. A. Glaser
- Department of Psychiatry, College of Medicine, University of Kentucky, Lexington, KY 40536, USA
- Department of Anatomy and Neurobiology, College of Medicine, University of Kentucky, Lexington, KY 40536, USA
- Department of Pediatrics, College of Medicine, University of Kentucky, Lexington, KY 40536, USA
| | - Megan M. Poole
- Department of Psychology, College of Arts and Science, University of Kentucky, Lexington, KY 40536, USA
| | - Craig R. Rush
- Department of Behavioral Science, College of Medicine, University of Kentucky, Lexington, KY 40536, USA
- Department of Psychiatry, College of Medicine, University of Kentucky, Lexington, KY 40536, USA
- Department of Psychology, College of Arts and Science, University of Kentucky Lexington, KY 40536, USA
- Department of Behavioral Science, University of Kentucky Medical Center, 140 Medical Behavioral Science Building, Lexington, KY, USA
| |
Collapse
|
153
|
Liang J, Zheng X, Chen J, Li Y, Xing X, Bai Y, Li Y. Roles of BDNF, dopamine D(3) receptors, and their interactions in the expression of morphine-induced context-specific locomotor sensitization. Eur Neuropsychopharmacol 2011; 21:825-34. [PMID: 21277174 DOI: 10.1016/j.euroneuro.2010.12.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Revised: 12/03/2010] [Accepted: 12/28/2010] [Indexed: 11/28/2022]
Abstract
Drug seeking, craving, and relapse can be triggered by environmental stimuli that acquire motivational salience through repeated associations with the drug's effects. Previous studies indicated that the dopamine D(3) receptor (Drd3) might be involved in the expression of drug-conditioned responses in rats, and brain-derived neurotrophic factor (BDNF) could modulate Drd3 expression in the nucleus accumbens (NAc). However, the involvement of neural regions with Drd3 activation and the underlying interaction between BDNF and Drd3 in the expression of behavioral responses controlled by a drug-associated environment have remained poorly understood. The present study used a conditioning procedure to assess the roles of BDNF, Drd3, and their interactions in the NAc in the expression of morphine-induced context-specific locomotor sensitization. We showed that the expression of locomotor sensitization in the morphine-paired environment was accompanied by significantly increased expression of Drd3 mRNA and BDNF mRNA and protein levels. Both sensitized locomotion in morphine-paired rats and enhanced Drd3 mRNA were suppressed by intra-NAc infusion of anti-tyrosine kinase receptor B (TrkB) IgG. Furthermore, intra-NAc infusion of the Drd3-selective antagonist SB-277011A significantly decreased the expression of context-specific locomotor sensitization and upregulated BDNF mRNA. Altogether, these results suggest that BDNF/TrkB signaling and activation of Drd3 in the NAc are required for the expression of morphine-induced context-specific locomotor sensitization.
Collapse
Affiliation(s)
- Jing Liang
- Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing 100101, PR China
| | | | | | | | | | | | | |
Collapse
|
154
|
Abstract
Investigations of long-term changes in brain structure and function that accompany chronic exposure to drugs of abuse suggest that alterations in gene regulation contribute substantially to the addictive phenotype. Here, we review multiple mechanisms by which drugs alter the transcriptional potential of genes. These mechanisms range from the mobilization or repression of the transcriptional machinery - including the transcription factors ΔFOSB, cyclic AMP-responsive element binding protein (CREB) and nuclear factor-κB (NF-κB) - to epigenetics - including alterations in the accessibility of genes within their native chromatin structure induced by histone tail modifications and DNA methylation, and the regulation of gene expression by non-coding RNAs. Increasing evidence implicates these various mechanisms of gene regulation in the lasting changes that drugs of abuse induce in the brain, and offers novel inroads for addiction therapy.
Collapse
|
155
|
Hong CJ, Liou YJ, Tsai SJ. Effects of BDNF polymorphisms on brain function and behavior in health and disease. Brain Res Bull 2011; 86:287-97. [PMID: 21924328 DOI: 10.1016/j.brainresbull.2011.08.019] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Revised: 08/22/2011] [Accepted: 08/31/2011] [Indexed: 12/25/2022]
Abstract
Brain-derived neurotrophic factor (BDNF), the most abundant neurotrophin in the brain, serves an important role during brain development and in synaptic plasticity. Given its pleiotropic effects in the central nervous system, BDNF has been implicated in cognitive function and personality development as well as the pathogenesis of various psychiatric disorders. Thus, BDNF is considered an attractive candidate gene for the study of healthy and diseased brain function and behaviors. Over the past decade, many studies have tested BDNF genetic association, particularly its functional Val66Met polymorphism, with psychiatric diseases, personality disorders, and cognitive function. Although many reports indicated a possible role for BDNF genetic effects in mental problems or brain function, other reports were unable to replicate the findings. The conflicting results in BDNF genetic studies may result from confounding factors such as age, gender, other environmental factors, sample size, ethnicity and phenotype assessment. Future studies with more homogenous populations, well-controlled confounding factors, and well-defined phenotypes are needed to clarify the BDNF genetic effects on mental diseases and human behaviors.
Collapse
Affiliation(s)
- Chen-Jee Hong
- Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan
| | | | | |
Collapse
|
156
|
He YY, Xue YX, Wang JS, Fang Q, Liu JF, Xue LF, Lu L. PKMζ maintains drug reward and aversion memory in the basolateral amygdala and extinction memory in the infralimbic cortex. Neuropsychopharmacology 2011; 36:1972-81. [PMID: 21633338 PMCID: PMC3158313 DOI: 10.1038/npp.2011.63] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The intense associative memories that develop between drug-paired contextual cues and rewarding stimuli or the drug withdrawal-associated aversive feeling have been suggested to contribute to the high rate of relapse. Various studies have elucidated the mechanisms underlying the formation and expression of drug-related cue memories, but how this mechanism is maintained is unknown. Protein kinase M ζ (PKMζ) was recently shown to be necessary and sufficient for long-term potentiation maintenance and memory storage. In the present study, we used conditioned place preference (CPP) and aversion (CPA) to examine whether PKMζ maintains both morphine-associated reward memory and morphine withdrawal-associated aversive memory in the basolateral amygdala (BLA). We also investigate the role of PKMζ in the infralimbic cortex in the extinction memory of morphine reward-related cues and morphine withdrawal-related aversive cues. We found that intra-BLA but not central nucleus of the amygdala injection of the selective PKMζ inhibitor ZIP 1 day after CPP and CPA training impaired the expression of CPP and CPA 1 day later, and the effect of ZIP on memory lasted at least 2 weeks. Inhibiting PKMζ activity in the infralimbic cortex, but not prelimbic cortex, disrupted the expression of the extinction memory of CPP and CPA. These results indicate that PKMζ in the BLA is required for the maintenance of associative morphine reward memory and morphine withdrawal-associated aversion memory, and PKMζ in the infralimbic cortex is required for the maintenance of extinction memory of morphine reward-related cues and morphine withdrawal-related aversive cues.
Collapse
Affiliation(s)
- Ying-Ying He
- Affiliated Hospital and School of Pharmacy of Guiyang Medical University, Guiyang, China,National Institute on Drug Dependence, Peking University, Beijing, China
| | - Yan-Xue Xue
- National Institute on Drug Dependence, Peking University, Beijing, China
| | - Ji-shi Wang
- Affiliated Hospital and School of Pharmacy of Guiyang Medical University, Guiyang, China,Affiliated Hospital of Guiyang Medical College, Guiyang 550004, China. Tel: +86 851 675 7898; Fax: +86 851 675 7898; E-mail:
| | - Qin Fang
- Affiliated Hospital and School of Pharmacy of Guiyang Medical University, Guiyang, China
| | - Jian-Feng Liu
- National Institute on Drug Dependence, Peking University, Beijing, China
| | - Li-Fen Xue
- National Institute on Drug Dependence, Peking University, Beijing, China
| | - Lin Lu
- National Institute on Drug Dependence, Peking University, Beijing, China,National Institute on Drug Dependence, Peking University, Beijing 100191, China. Tel: +86 108 280 2459, Fax: +86 106 203 2624; E-mail:
| |
Collapse
|
157
|
Miladi-Gorji H, Rashidy-Pour A, Fathollahi Y, Akhavan MM, Semnanian S, Safari M. Voluntary exercise ameliorates cognitive deficits in morphine dependent rats: the role of hippocampal brain-derived neurotrophic factor. Neurobiol Learn Mem 2011; 96:479-91. [PMID: 21872672 DOI: 10.1016/j.nlm.2011.08.001] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Revised: 06/28/2011] [Accepted: 08/08/2011] [Indexed: 02/06/2023]
Abstract
Chronic exposure to opiates impairs spatial learning and memory. Given the well-known beneficial effects of voluntary exercise on cognitive functions, we investigated whether voluntary exercise would ameliorate the cognitive deficits that are induced by morphine dependence. If an effect of exercise was observed, we aimed to investigate the possible role of hippocampal brain-derived neurotrophic factor (BDNF) in the exercise-induced enhancement of learning and memory in morphine-dependent rats. The rats were injected with bi-daily doses (10mg/kg, at 12h intervals) of morphine over a period of 10 days of voluntary exercise. Following these injections, a water maze task was performed twice a day for five consecutive days, followed by a probe trial 2 days later. A specific BDNF inhibitor (TrkB-IgG chimera) was used to block the hippocampal BDNF action during the 10 days of voluntary exercise. We found that voluntary exercise blocked the ability of chronic morphine to impair spatial memory retention. A blockade of the BDNF action blunted the exercise-induced improvement of spatial memory in the dependent rats. Moreover, the voluntary exercise diminished the severity of the rats' dependency on morphine. This study demonstrates that voluntary exercise ameliorates, via a TrkB-mediated mechanism, the cognitive deficits that are induced by chronic morphine. Thus, voluntary exercise might be a potential method to ameliorate some of the deleterious behavioral consequences of the abuse of morphine and other opiates.
Collapse
Affiliation(s)
- Hossein Miladi-Gorji
- Dept. of Physiology, School of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | | | | | | | | | | |
Collapse
|
158
|
Su N, Zhang L, Fei F, Hu H, Wang K, Hui H, Jiang XF, Li X, Zhen HN, Li J, Cao BP, Dang W, Qu Y, Zhou F. The brain-derived neurotrophic factor is associated with alcohol dependence-related depression and antidepressant response. Brain Res 2011; 1415:119-26. [PMID: 21880305 DOI: 10.1016/j.brainres.2011.08.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Revised: 07/14/2011] [Accepted: 08/03/2011] [Indexed: 11/30/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) plays an essential role in neuronal survival, proliferation, and synaptic remodeling and modulates the function of many other neurotransmitters. Additionally, it likely underlies neurodegenerative and psychiatric disorders, including alcohol dependence-related depression (AD-D). Here, we investigated the possible association between three single nucleotide polymorphisms (SNPs) of the BDNF gene (rs13306221, rs6265, rs16917204) and AD-D. Of 548 patients with alcohol dependence (AD), 166 had AD-D and 312 healthy controls. Response to 8-week sertraline treatment was also assessed. The frequency of the A allele of rs6265 (Val66Met) was significantly higher in AD-D patients than in the healthy controls (p=0.009 after Bonferroni correction). The analysis revealed a strong association between the rs6265 genotype distribution and AD-D (p=0.005 after Bonferroni correction), and the A allele of rs6265 was significantly overrepresented in AD-D patients compared to AD without depression (AD-nD) patients (p=0.001 after Bonferroni correction). Additionally, carriers of the A allele of rs6265 responded better to sertraline treatment (p=0.001). Our results suggested a novel association between BDNF rs6265 and AD-D. These findings might lead to earlier detection of AD-D, perhaps providing better tools for clinical care of these patients in the future.
Collapse
Affiliation(s)
- N Su
- Department of Neurosurgery, Xi Jing Hospital, Fourth Military Medical University, Xi'an, Shannxi, PR China.
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
159
|
Pickens CL, Airavaara M, Theberge F, Fanous S, Hope BT, Shaham Y. Neurobiology of the incubation of drug craving. Trends Neurosci 2011; 34:411-20. [PMID: 21764143 PMCID: PMC3152666 DOI: 10.1016/j.tins.2011.06.001] [Citation(s) in RCA: 443] [Impact Index Per Article: 34.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Revised: 06/02/2011] [Accepted: 06/02/2011] [Indexed: 12/20/2022]
Abstract
It was suggested in 1986 that cue-induced drug craving in cocaine addicts progressively increases over the first several weeks of abstinence and remains high for extended periods. During the past decade, investigators have identified an analogous incubation phenomenon in rodents, in which time-dependent increases in cue-induced drug seeking are observed after withdrawal from intravenous cocaine self-administration. Such an incubation of drug craving is not specific to cocaine, as similar findings have been observed after self-administration of heroin, nicotine, methamphetamine and alcohol in rats. In this review, we discuss recent results that have identified important brain regions involved in the incubation of drug craving, as well as evidence for the underlying cellular mechanisms. Understanding the neurobiology of the incubation of drug craving in rodents is likely to have significant implications for furthering understanding of brain mechanisms and circuits that underlie craving and relapse in human addicts.
Collapse
Affiliation(s)
| | | | - Florence Theberge
- Intramural Research Program, National Institute on Drug Addiction (NIDA), National Institute of Health (NIH), 251 Bayview Blvd, Baltimore, Maryland, 21224, USA
| | - Sanya Fanous
- Intramural Research Program, National Institute on Drug Addiction (NIDA), National Institute of Health (NIH), 251 Bayview Blvd, Baltimore, Maryland, 21224, USA
| | - Bruce T. Hope
- Intramural Research Program, National Institute on Drug Addiction (NIDA), National Institute of Health (NIH), 251 Bayview Blvd, Baltimore, Maryland, 21224, USA
| | - Yavin Shaham
- Intramural Research Program, National Institute on Drug Addiction (NIDA), National Institute of Health (NIH), 251 Bayview Blvd, Baltimore, Maryland, 21224, USA
| |
Collapse
|
160
|
McGinty JF, Bache AJ, Coleman NT, Sun WL. The Role of BDNF/TrkB Signaling in Acute Amphetamine-Induced Locomotor Activity and Opioid Peptide Gene Expression in the Rat Dorsal Striatum. Front Syst Neurosci 2011; 5:60. [PMID: 21811445 PMCID: PMC3143721 DOI: 10.3389/fnsys.2011.00060] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Accepted: 06/27/2011] [Indexed: 01/15/2023] Open
Abstract
Exposure to psychostimulants increases brain-derived neurotrophic factor (BDNF) mRNA and protein levels in the cerebral cortex and subcortical structures. Because BDNF is co-localized with dopamine and glutamate in afferents to the striatum of rats, it may be co-released with those neurotransmitters upon stimulation. Further, there may be an interaction between the intracellular signaling cascades activated by dopamine, glutamate, and TrkB receptors in medium spiny striatal neurons. In the present study, the effect of acute amphetamine administration on TrkB phosphorylation, as an indirect indicator of activation, and striatal gene expression, was evaluated. In Experiment 1, 15 min or 2 h after a single saline or amphetamine (2.5 mg/kg, i.p.) injection, the caudate–putamen (CPu), nucleus accumbens (NAc), and dorsomedial prefrontal cortex (dmPFC) were extracted and processed for phospho (p)-TrkB immunoreactivity. Immunoprecipitation analyses indicated that neither the tyrosine phosphorylation (p-Tyr) or autophosphorylation sites of TrkB (706) were changed in NAc, CPu, or dmPFC 15 min after amphetamine administration. In contrast, p-Tyr and the PLCγ phosphorylation site of TrkB (816) were increased in the NAc and CPu 2 h after amphetamine. In Experiment 2, intra-striatal infusion of the tyrosine kinase inhibitor, K252a, increased amphetamine-induced vertical activity but not total distance traveled. In addition, K252a inhibited amphetamine-induced preprodynorphin, but not preproenkephalin, mRNA expression in the striatum. These data indicate that acute amphetamine administration induces p-TrkB activation and signaling in a time- and brain region-dependent manner and that TrkB/BDNF signaling plays an important role in amphetamine-induced behavior and striatal gene expression.
Collapse
Affiliation(s)
- Jacqueline F McGinty
- Department of Neurosciences, Medical University of South Carolina Charleston, SC, USA
| | | | | | | |
Collapse
|
161
|
Kuzirian MS, Paradis S. Emerging themes in GABAergic synapse development. Prog Neurobiol 2011; 95:68-87. [PMID: 21798307 DOI: 10.1016/j.pneurobio.2011.07.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Revised: 06/30/2011] [Accepted: 07/03/2011] [Indexed: 12/25/2022]
Abstract
Glutamatergic synapse development has been rigorously investigated for the past two decades at both the molecular and cell biological level yet a comparable intensity of investigation into the cellular and molecular mechanisms of GABAergic synapse development has been lacking until relatively recently. This review will provide a detailed overview of the current understanding of GABAergic synapse development with a particular emphasis on assembly of synaptic components, molecular mechanisms of synaptic development, and a subset of human disorders which manifest when GABAergic synapse development is disrupted. An unexpected and emerging theme from these studies is that glutamatergic and GABAergic synapse development share a number of overlapping molecular and cell biological mechanisms that will be emphasized in this review.
Collapse
Affiliation(s)
- Marissa S Kuzirian
- Brandeis Univeristy, Department of Biology, National Center for Behavioral Genomics, Volen Center for Complex Systems, Waltham, MA 02453, USA
| | | |
Collapse
|
162
|
Fernandez-Espejo E, Rodriguez-Espinosa N. Psychostimulant Drugs and Neuroplasticity. Pharmaceuticals (Basel) 2011. [PMCID: PMC4058673 DOI: 10.3390/ph4070976] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Drugs of abuse induce plastic changes in the brain that seem to underlie addictive phenomena. These plastic changes can be structural (morphological) or synaptic (biochemical), and most of them take place in the mesolimbic and mesostriatal circuits. Several addiction-related changes in brain circuits (hypofrontality, sensitization, tolerance) as well as the outcome of treatment have been visualized in addicts to psychostimulants using neuroimaging techniques. Repeated exposure to psychostimulants induces morphological changes such as increase in the number of dendritic spines, changes in the morphology of dendritic spines, and altered cellular coupling through new gap junctions. Repeated exposure to psychostimulants also induces various synaptic adaptations, many of them related to sensitization and neuroplastic processes, that include up- or down-regulation of D1, D2 and D3 dopamine receptors, changes in subunits of G proteins, increased adenylyl cyclase activity, cyclic AMP and protein kinase A in the nucleus accumbens, increased tyrosine hydroxylase enzyme activity, increased calmodulin and activated CaMKII in the ventral tegmental area, and increased deltaFosB, c-Fos and AP-1 binding proteins. Most of these changes are transient, suggesting that more lasting plastic brain adaptations should take place. In this context, protein synthesis inhibitors block the development of sensitization to cocaine, indicating that rearrangement of neural networks must develop for the long-lasting plasticity required for addiction to occur. Self-administration studies indicate the importance of glutamate neurotransmission in neuroplastic changes underlying transition from use to abuse. Finally, plastic changes in the addicted brain are enhanced and aggravated by neuroinflammation and neurotrophic disbalance after repeated psychostimulants.
Collapse
Affiliation(s)
- Emilio Fernandez-Espejo
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +34-95-455-6584; Fax: +34-95-455-1769
| | | |
Collapse
|
163
|
Numakawa T, Richards M, Adachi N, Kishi S, Kunugi H, Hashido K. MicroRNA function and neurotrophin BDNF. Neurochem Int 2011; 59:551-8. [PMID: 21723895 DOI: 10.1016/j.neuint.2011.06.009] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Revised: 06/15/2011] [Accepted: 06/16/2011] [Indexed: 12/11/2022]
Abstract
MicroRNAs (miRs), endogenous small RNAs, regulate gene expression through repression of translational activity after binding to target mRNAs. miRs are involved in various cellular processes including differentiation, metabolism, and apoptosis. Furthermore, possible involvement of miRs in neuronal function have been proposed. For example, miR-132 is closely related to neuronal outgrowth while miR-134 plays a role in postsynaptic regulation, suggesting that brain-specific miRs are critical for synaptic plasticity. On the other hand, numerous studies indicate that BDNF (brain-derived neurotrophic factor), one of the neurotrophins, is essential for a variety of neuronal aspects such as cell differentiation, survival, and synaptic plasticity in the central nervous system (CNS). Interestingly, recent studies, including ours, suggest that BDNF exerts its beneficial effects on CNS neurons via up-regulation of miR-132. Here, we present a broad overview of the current knowledge concerning the association between neurotrophins and various miRs.
Collapse
Affiliation(s)
- Tadahiro Numakawa
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Tokyo 187-8502, Japan.
| | | | | | | | | | | |
Collapse
|
164
|
Li X, Wolf ME. Brain-derived neurotrophic factor rapidly increases AMPA receptor surface expression in rat nucleus accumbens. Eur J Neurosci 2011; 34:190-8. [PMID: 21692887 DOI: 10.1111/j.1460-9568.2011.07754.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In the rodent nucleus accumbens (NAc), cocaine elevates levels of brain-derived neurotrophic factor (BDNF). Conversely, BDNF can augment cocaine-related behavioral responses. The latter could reflect enhancement of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) transmission, because AMPARs in the NAc mediate some cocaine-induced behaviors. Furthermore, in vitro studies in other cell types show that BDNF can promote AMPAR synaptic delivery. In this study, we investigated whether BDNF similarly promotes AMPAR trafficking in the adult rat NAc. After unilateral intracranial injection of BDNF into NAc core or shell, rats were killed at post-injection times ranging from 30 min to 3 days. NAc core or shell tissue from both injected and non-injected hemispheres was analysed by Western blotting. A protein cross-linking assay was used to measure AMPAR surface expression. Assessment of tropomyosin receptor kinase B signaling demonstrated that injected BDNF was biologically active. BDNF injection into NAc core, but not NAc shell, led to a protein synthesis- and extracellular signal-regulated kinase-dependent increase in cell surface GluA1 and a trend towards increased total GluA1. This was detected 30 min post-injection but not at longer time-points. GluA2 and GluA3 were unaffected, suggesting an effect of BDNF on homomeric GluA1 Ca(2+) -permeable AMPARs. These results demonstrate that exogenous BDNF rapidly increases AMPAR surface expression in the rat NAc core, raising the possibility of a relationship between increases in endogenous BDNF levels and alterations in AMPAR transmission observed in the NAc of cocaine-experienced rats.
Collapse
Affiliation(s)
- Xuan Li
- Department of Neuroscience, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064-3095, USA
| | | |
Collapse
|
165
|
Katz JL, Su TP, Hiranita T, Hayashi T, Tanda G, Kopajtic T, Tsai SY. A Role for Sigma Receptors in Stimulant Self Administration and Addiction. Pharmaceuticals (Basel) 2011; 4:880-914. [PMID: 21904468 PMCID: PMC3167211 DOI: 10.3390/ph4060880] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Sigma1 receptors (σ1Rs) represent a structurally unique class of intracellular proteins that function as chaperones. σ1Rs translocate from the mitochondria-associated membrane to the cell nucleus or cell membrane, and through protein-protein interactions influence several targets, including ion channels, G-protein-coupled receptors, lipids, and other signaling proteins. Several studies have demonstrated that σR antagonists block stimulant-induced behavioral effects, including ambulatory activity, sensitization, and acute toxicities. Curiously, the effects of stimulants have been blocked by σR antagonists tested under place-conditioning but not self-administration procedures, indicating fundamental differences in the mechanisms underlying these two effects. The self administration of σR agonists has been found in subjects previously trained to self administer cocaine. The reinforcing effects of the σR agonists were blocked by σR antagonists. Additionally, σR agonists were found to increase dopamine concentrations in the nucleus accumbens shell, a brain region considered important for the reinforcing effects of abused drugs. Although the effects of the σR agonist, DTG, on dopamine were obtained at doses that approximated those that maintained self administration behavior those of another agonist, PRE-084 required higher doses. The effects of DTG were antagonized by non-selective or a preferential σ2R antagonist but not by a preferential σ1R antagonist. The effects of PRE-084 on dopamine were insensitive to σR antagonists. The data suggest that the self administration of σR agonists is independent of dopamine and the findings are discussed in light of a hypothesis that cocaine has both intracellular actions mediated by σRs, as well as extracellular actions mediated through conventionally studied mechanisms. The co-activation and potential interactions among these mechanisms, in particular those involving the intracellular chaperone σRs, may lead to the pernicious addictive effects of stimulant drugs.
Collapse
|
166
|
Wolstenholme JT, Warner JA, Capparuccini MI, Archer KJ, Shelton KL, Miles MF. Genomic analysis of individual differences in ethanol drinking: evidence for non-genetic factors in C57BL/6 mice. PLoS One 2011; 6:e21100. [PMID: 21698166 PMCID: PMC3116881 DOI: 10.1371/journal.pone.0021100] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2010] [Accepted: 05/20/2011] [Indexed: 01/26/2023] Open
Abstract
Genetic analysis of factors affecting risk to develop excessive ethanol drinking has been extensively studied in humans and animal models for over 20 years. However, little progress has been made in determining molecular mechanisms underlying environmental or non-genetic events contributing to variation in ethanol drinking. Here, we identify persistent and substantial variation in ethanol drinking behavior within an inbred mouse strain and utilize this model to identify gene networks influencing such “non-genetic” variation in ethanol intake. C57BL/6NCrl mice showed persistent inter-individual variation of ethanol intake in a two-bottle choice paradigm over a three-week period, ranging from less than 1 g/kg to over 14 g/kg ethanol in an 18 h interval. Differences in sweet or bitter taste susceptibility or litter effects did not appreciably correlate with ethanol intake variation. Whole genome microarray expression analysis in nucleus accumbens, prefrontal cortex and ventral midbrain region of individual animals identified gene expression patterns correlated with ethanol intake. Results included several gene networks previously implicated in ethanol behaviors, such as glutamate signaling, BDNF and genes involved in synaptic vesicle function. Additionally, genes functioning in epigenetic chromatin or DNA modifications such as acetylation and/or methylation also had expression patterns correlated with ethanol intake. In verification for the significance of the expression findings, we found that a histone deacetylase inhibitor, trichostatin A, caused an increase in 2-bottle ethanol intake. Our results thus implicate specific brain regional gene networks, including chromatin modification factors, as potentially important mechanisms underlying individual variation in ethanol intake.
Collapse
Affiliation(s)
- Jennifer T. Wolstenholme
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Jon A. Warner
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Maria I. Capparuccini
- Department of Biostatistics, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Kellie J. Archer
- Department of Biostatistics, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Keith L. Shelton
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Michael F. Miles
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Department of Neurology, Virginia Commonwealth University, Richmond, Virginia, United States of America
- * E-mail:
| |
Collapse
|
167
|
Peregud DI, Yakovlev AA, Panchenko LF, Gulyaeva NV. Expression of the mRNA of neurotrophins in brain regions of rats after spontaneous morphine withdrawal. NEUROCHEM J+ 2011. [DOI: 10.1134/s181971241102005x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
168
|
Crews FT, Zou J, Qin L. Induction of innate immune genes in brain create the neurobiology of addiction. Brain Behav Immun 2011; 25 Suppl 1:S4-S12. [PMID: 21402143 PMCID: PMC3552373 DOI: 10.1016/j.bbi.2011.03.003] [Citation(s) in RCA: 223] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Revised: 03/03/2011] [Accepted: 03/03/2011] [Indexed: 12/27/2022] Open
Abstract
Addiction occurs through repeated abuse of drugs that progressively reduce behavioral control and cognitive flexibility while increasing limbic negative emotion. Recent discoveries indicate neuroimmune signaling underlies addiction and co-morbid depression. Low threshold microglia undergo progressive stages of innate immune activation involving astrocytes and neurons with repeated drug abuse, stress, and/or cell damage signals. Increased brain NF-κB transcription of proinflammatory chemokines, cytokines, oxidases, proteases, TLR and other genes create loops amplifying NF-κB transcription and innate immune target gene expression. Human post-mortem alcoholic brain has increased NF-κB and NF-κB target gene message, increased microglial markers and chemokine-MCP1. Polymorphisms of human NF-κB1 and other innate immune genes contribute to genetic risk for alcoholism. Animal transgenic and genetic studies link NF-κB innate immune gene expression to alcohol drinking. Human drug addicts show deficits in behavioral flexibility modeled pre-clinically using reversal learning. Binge alcohol, chronic cocaine, and lesions link addiction neurobiology to frontal cortex, neuroimmune signaling and loss of behavioral flexibility. Addiction also involves increasing limbic negative emotion and depression-like behavior that is reflected in hippocampal neurogenesis. Innate immune activation parallels loss of neurogenesis and increased depression-like behavior. Protection against loss of neurogenesis and negative affect by anti-oxidant, anti-inflammatory, anti-depressant, opiate antagonist and abstinence from ethanol dependence link limbic affect to changes in innate immune signaling. The hypothesis that innate immune gene induction underlies addiction and affective disorders creates new targets for therapy.
Collapse
Affiliation(s)
- FT Crews
- Bowles Center for Alcohol Studies, Department of Pharmacology and Psychiatry, School of Medicine, The University of North Carolina at Chapel Hill, Thurston-Bowles Building, CB 7178, Chapel Hill, NC 27599-7178
| | - Jian Zou
- Bowles Center for Alcohol Studies, Department of Pharmacology and Psychiatry, School of Medicine, The University of North Carolina at Chapel Hill, Thurston-Bowles Building, CB 7178, Chapel Hill, NC 27599-7178
| | - Liya Qin
- Bowles Center for Alcohol Studies, Department of Pharmacology and Psychiatry, School of Medicine, The University of North Carolina at Chapel Hill, Thurston-Bowles Building, CB 7178, Chapel Hill, NC 27599-7178
| |
Collapse
|
169
|
Abstract
This essay explores four answers to the question 'What kinds of things are psychiatric disorders?' Essentialist kinds are classes whose members share an essence from which their defining features arise. Although elegant and appropriate for some physical (e.g. atomic elements) and medical (e.g. Mendelian disorders) phenomena, this model is inappropriate for psychiatric disorders, which are multi-factorial and 'fuzzy'. Socially constructed kinds are classes whose members are defined by the cultural context in which they arise. This model excludes the importance of shared physiological mechanisms by which the same disorder could be identified across different cultures. Advocates of practical kinds put off metaphysical questions about 'reality' and focus on defining classes that are useful. Practical kinds models for psychiatric disorders, implicit in the DSM nosologies, do not require that diagnoses be grounded in shared causal processes. If psychiatry seeks to tie disorders to etiology and underlying mechanisms, a model first proposed for biological species, mechanistic property cluster (MPC) kinds, can provide a useful framework. MPC kinds are defined not in terms of essences but in terms of complex, mutually reinforcing networks of causal mechanisms. We argue that psychiatric disorders are objectively grounded features of the causal structure of the mind/brain. MPC kinds are fuzzy sets defined by mechanisms at multiple levels that act and interact to produce the key features of the kind. Like species, psychiatric disorders are populations with central paradigmatic and more marginal members. The MPC view is the best current answer to 'What kinds of things are psychiatric disorders?'
Collapse
Affiliation(s)
- K S Kendler
- Department of Psychiatry, Virginia Institute for Psychiatric and Behavioral Genetics, Richmond, VA, USA.
| | | | | |
Collapse
|
170
|
Jia W, Shi J, Wu B, Ao L, Zhang R, Zhu Y. Polymorphisms of brain-derived neurotrophic factor associated with heroin dependence. Neurosci Lett 2011; 495:221-4. [DOI: 10.1016/j.neulet.2011.03.072] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Revised: 03/23/2011] [Accepted: 03/24/2011] [Indexed: 01/27/2023]
|
171
|
Sex differences and effects of cocaine on excitatory synapses in the nucleus accumbens. Neuropharmacology 2011; 61:217-27. [PMID: 21510962 DOI: 10.1016/j.neuropharm.2011.04.002] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2010] [Revised: 03/16/2011] [Accepted: 04/01/2011] [Indexed: 12/11/2022]
Abstract
Human and animal studies indicate that drugs of abuse affect males and females differently, but the mechanism(s) underlying sex differences are unknown. The nucleus accumbens (NAc) is central in the neural circuitry of addiction and medium spiny neurons (MSNs) in the NAc show drug-induced changes in morphology and physiology including increased dendritic spine density. We previously showed in drug-naïve rats that MSN dendritic spine density is higher in females than males. In this study, we investigated sex differences in the effects of cocaine on locomotor activity as well as MSN dendritic spine density and excitatory synaptic physiology in rats treated for 5 weeks followed by 17-21 days of abstinence. Females showed a greater locomotor response to cocaine and more robust behavioral sensitization than males. Spine density was also higher in females and, particularly in the core of the NAc, the magnitude of the cocaine-induced increase in spine density was greater in females. Interestingly, in cocaine-treated females but not males, cocaine-induced behavioral activation during treatment was correlated with spine density measured after treatment. Miniature EPSC (mEPSC) frequency in core MSNs also was higher in females, and increased with cocaine in both the core and shell of females more than males. We found no differences in mEPSC amplitude or paired-pulse ratio of evoked EPSCs, suggesting that sex differences and cocaine effects on mEPSC frequency reflect differences in excitatory synapse number per neuron rather than presynaptic release probability. These studies are the first to demonstrate structural and electrophysiological differences between males and females that may drive sex differences in addictive behavior.
Collapse
|
172
|
Airavaara M, Pickens CL, Stern AL, Wihbey KA, Harvey BK, Bossert JM, Liu QR, Hoffer BJ, Shaham Y. Endogenous GDNF in ventral tegmental area and nucleus accumbens does not play a role in the incubation of heroin craving. Addict Biol 2011; 16:261-72. [PMID: 21182575 DOI: 10.1111/j.1369-1600.2010.00281.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Glial cell line-derived neurotrophic factor (GDNF) activity in ventral tegmental area (VTA) mediates the time-dependent increases in cue-induced cocaine-seeking after withdrawal (incubation of cocaine craving). Here, we studied the generality of these findings to incubation of heroin craving. Rats were trained to self-administer heroin for 10 days (6 hours/day; 0.075 mg/kg/infusion; infusions were paired with a tone-light cue) and tested for cue-induced heroin-seeking in extinction tests after 1, 11 or 30 withdrawal days. Cue-induced heroin seeking was higher after 11 or 30 days than after 1 day (incubation of heroin craving), and the time-dependent increases in extinction responding were associated with time-dependent changes in GDNF mRNA expression in VTA and nucleus accumbens. Additionally, acute accumbens (but not VTA) GDNF injections (12.5 µg/side) administered 1-3 hours after the last heroin self-administration training session enhanced the time-dependent increases in extinction responding after withdrawal. However, the time-dependent increases in extinction responding after withdrawal were not associated with changes in GDNF protein expression in VTA and accumbens. Additionally, interfering with endogenous GDNF function by chronic delivery of anti-GDNF monoclonal neutralizing antibodies (600 ng/side/day) into VTA or accumbens had no effect on the time-dependent increases in extinction responding. In summary, heroin self-administration and withdrawal regulate VTA and accumbens GDNF mRNA expression in a time-dependent manner, and exogenous GDNF administration into accumbens but not VTA potentiates cue-induced heroin seeking. However, based on the GDNF protein expression and the anti-GDNF monoclonal neutralizing antibodies manipulation data, we conclude that neither accumbens nor VTA endogenous GDNF mediates the incubation of heroin craving.
Collapse
Affiliation(s)
- Mikko Airavaara
- Intramural Research Program and National Institute on Drug Abuse, NIH, Baltimore, MD 21224, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
173
|
Zill P, Vielsmeier V, Büttner A, Eisenmenger W, Siedler F, Scheffer B, Möller HJ, Bondy B. Postmortem proteomic analysis in human amygdala of drug addicts: possible impact of tubulin on drug-abusing behavior. Eur Arch Psychiatry Clin Neurosci 2011; 261:121-31. [PMID: 20686780 DOI: 10.1007/s00406-010-0129-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Accepted: 07/23/2010] [Indexed: 10/19/2022]
Abstract
Besides the ventral tegmental area and the nucleus accumbens as the most investigated brain reward structures, several reports about the relation between volume and activity of the amygdala and drug-seeking behavior have emphasized the central role of the amygdala in the etiology of addiction. Considering its proposed important role and the limited number of human protein expression studies with amygdala in drug addiction, we performed a human postmortem proteomic analysis of amygdala tissue obtained from 8 opiate addicts and 7 control individuals. Results were validated by Western blot in an independent postmortem replication sample from 12 opiate addicts compared to 12 controls and 12 suicide victims, as a second "control sample". Applying 2D-electrophoresis and MALDI-TOF-MS analysis, we detected alterations of beta-tubulin expression and decreased levels of the heat-shock protein HSP60 in drug addicts. Western blot analysis in the additional sample demonstrated significantly increased alpha- and beta-tubulin concentrations in the amygdala of drug abusers versus controls (P = 0.021, 0.029) and to suicide victims (P = 0.006, 0.002). Our results suggest that cytoskeletal alterations in the amygdala determined by tubulin seem to be involved in the pathophysiology of drug addiction, probably via a relation to neurotransmission and cellular signaling. Moreover, the loss of neuroprotection against stressors by chaperons as HSP60 might also contribute to structural alteration in the brain of drug addicts. Although further studies have to confirm our results, this might be a possible pathway that may increase our understanding of drug addiction.
Collapse
Affiliation(s)
- P Zill
- Department of Psychiatry, Division of Psychiatric Genetics and Neurochemistry, Ludwig-Maximilians-University Munich, Nussbaumstrasse 7, 80336 Munich, Germany.
| | | | | | | | | | | | | | | |
Collapse
|
174
|
IκB kinase regulates social defeat stress-induced synaptic and behavioral plasticity. J Neurosci 2011; 31:314-21. [PMID: 21209217 DOI: 10.1523/jneurosci.4763-10.2011] [Citation(s) in RCA: 225] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The neurobiological underpinnings of mood and anxiety disorders have been linked to the nucleus accumbens (NAc), a region important in processing the rewarding and emotional salience of stimuli. Using chronic social defeat stress, an animal model of mood and anxiety disorders, we investigated whether alterations in synaptic plasticity are responsible for the long-lasting behavioral symptoms induced by this form of stress. We hypothesized that chronic social defeat stress alters synaptic strength or connectivity of medium spiny neurons (MSNs) in the NAc to induce social avoidance. To test this, we analyzed the synaptic profile of MSNs via confocal imaging of Lucifer-yellow-filled cells, ultrastructural analysis of the postsynaptic density, and electrophysiological recordings of miniature EPSCs (mEPSCs) in mice after social defeat. We found that NAc MSNs have more stubby spine structures with smaller postsynaptic densities and an increase in the frequency of mEPSCs after social defeat. In parallel to these structural changes, we observed significant increases in IκB kinase (IKK) in the NAc after social defeat, a molecular pathway that has been shown to regulate neuronal morphology. Indeed, we find using viral-mediated gene transfer of dominant-negative and constitutively active IKK mutants that activation of IKK signaling pathways during social defeat is both necessary and sufficient to induce synaptic alterations and behavioral effects of the stress. These studies establish a causal role for IKK in regulating stress-induced adaptive plasticity and may present a novel target for drug development in the treatment of mood and anxiety disorders in humans.
Collapse
|
175
|
Niehaus JL, Murali M, Kauer JA. Drugs of abuse and stress impair LTP at inhibitory synapses in the ventral tegmental area. Eur J Neurosci 2011; 32:108-17. [PMID: 20608969 DOI: 10.1111/j.1460-9568.2010.07256.x] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Synaptic plasticity in the ventral tegmental area (VTA) is modulated by drugs of abuse and stress and is hypothesized to contribute to specific aspects of addiction. Both excitatory and inhibitory synapses on dopamine neurons in the VTA are capable of undergoing long-term changes in synaptic strength. While the strengthening or weakening of excitatory synapses in the VTA has been widely examined, the role of inhibitory synaptic plasticity in brain reward circuitry is less established. Here, we investigated the effects of drugs of abuse, as well as acute stress, on long-term potentiation of GABAergic synapses onto VTA dopamine neurons (LTP(GABA)). Morphine (10 mg/kg i.p.) reduced the ability of inhibitory synapses in midbrain slices to express LTP(GABA) both at 2 and 24 h after drug exposure but not after 5 days. Cocaine (15 mg/kg i.p.) impaired LTP(GABA) 24 h after exposure, but not at 2 h. Nicotine (0.5 mg/kg i.p.) impaired LTP(GABA) 2 h after exposure, but not after 24 h. Furthermore, LTP(GABA) was completely blocked 24 h following brief exposure to a stressful stimulus, a forced swim task. Our data suggest that drugs of abuse and stress trigger a common modification to inhibitory plasticity, synergizing with their collective effect at excitatory synapses. Together, the net effect of addictive substances or stress is expected to increase excitability of VTA dopamine neurons, potentially contributing to the early stages of addiction.
Collapse
Affiliation(s)
- Jason L Niehaus
- Department of Molecular Pharmacology, Physiology and Biotechnology, Brown University, Providence, RI 02912, USA
| | | | | |
Collapse
|
176
|
Bountra C, Oppermann U, Heightman TD. Animal models of epigenetic regulation in neuropsychiatric disorders. Curr Top Behav Neurosci 2011; 7:281-322. [PMID: 21225415 DOI: 10.1007/7854_2010_104] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Epigenetics describes the phenomenon of heritable changes in gene regulation that are governed by non-Mendelian processes, primarily through biochemical modifications to chromatin structure that occur during cell development and differentiation. Numerous lines of evidence link abnormal levels of chromatin modifications (either to DNA, histones, or both) in patients with a wide variety of diseases including cancer, psychiatry, neurodegeneration, metabolic and inflammatory disorders. Drugs that target the proteins controlling chromatin modifications can modulate the expression of clusters of genes, potentially offering higher therapeutic efficacy than classical agents with single target pharmacologies that are susceptible to biochemical pathway degeneracy. Here, we summarize recent research linking epigenetic dysregulation with diseases in neurosciences, the application of relevant animal models, and the potential for small molecule modulator development to facilitate target discovery, validation and translation into clinical treatments.
Collapse
Affiliation(s)
- Chas Bountra
- Structural Genomics Consortium, University of Oxford, Oxford, OX3 7DQ, UK,
| | | | | |
Collapse
|
177
|
Crews FT, Vetreno RP. Addiction, adolescence, and innate immune gene induction. Front Psychiatry 2011; 2:19. [PMID: 21629837 PMCID: PMC3098669 DOI: 10.3389/fpsyt.2011.00019] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Accepted: 04/11/2011] [Indexed: 01/12/2023] Open
Abstract
Repeated drug use/abuse amplifies psychopathology, progressively reducing frontal lobe behavioral control, and cognitive flexibility while simultaneously increasing limbic temporal lobe negative emotionality. The period of adolescence is a neurodevelopmental stage characterized by poor behavioral control as well as strong limbic reward and thrill seeking. Repeated drug abuse and/or stress during this stage increase the risk of addiction and elevate activator innate immune signaling in the brain. Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) is a key glial transcription factor that regulates proinflammatory chemokines, cytokines, oxidases, proteases, and other innate immune genes. Induction of innate brain immune gene expression (e.g., NF-κB) facilitates negative affect, depression-like behaviors, and inhibits hippocampal neurogenesis. In addition, innate immune gene induction alters cortical neurotransmission consistent with loss of behavioral control. Studies with anti-oxidant, anti-inflammatory, and anti-depressant drugs as well as opiate antagonists link persistent innate immune gene expression to key behavioral components of addiction, e.g., negative affect-anxiety and loss of frontal-cortical behavioral control. This review suggests that persistent and progressive changes in innate immune gene expression contribute to the development of addiction. Innate immune genes may represent a novel new target for addiction therapy.
Collapse
Affiliation(s)
- Fulton T Crews
- Department of Pharmacology, Bowles Center for Alcohol Studies, The University of North Carolina at Chapel Hill Chapel Hill, NC, USA
| | | |
Collapse
|
178
|
Balu DT, Coyle JT. Neuroplasticity signaling pathways linked to the pathophysiology of schizophrenia. Neurosci Biobehav Rev 2011; 35:848-70. [PMID: 20951727 PMCID: PMC3005823 DOI: 10.1016/j.neubiorev.2010.10.005] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2010] [Revised: 10/06/2010] [Accepted: 10/10/2010] [Indexed: 12/15/2022]
Abstract
Schizophrenia is a severe mental illness that afflicts nearly 1% of the world's population. One of the cardinal pathological features of schizophrenia is perturbation in synaptic connectivity. Although the etiology of schizophrenia is unknown, it appears to be a developmental disorder involving the interaction of a potentially large number of risk genes, with no one gene producing a strong effect except rare, highly penetrant copy number variants. The purpose of this review is to detail how putative schizophrenia risk genes (DISC-1, neuregulin/ErbB4, dysbindin, Akt1, BDNF, and the NMDA receptor) are involved in regulating neuroplasticity and how alterations in their expression may contribute to the disconnectivity observed in schizophrenia. Moreover, this review highlights how many of these risk genes converge to regulate common neurotransmitter systems and signaling pathways. Future studies aimed at elucidating the functions of these risk genes will provide new insights into the pathophysiology of schizophrenia and will likely lead to the nomination of novel therapeutic targets for restoring proper synaptic connectivity in the brain in schizophrenia and related disorders.
Collapse
Affiliation(s)
- Darrick T Balu
- Department of Psychiatry, Harvard Medical School, Belmont, MA, USA.
| | | |
Collapse
|
179
|
Uys JD, Reissner KJ. Glutamatergic Neuroplasticity in Cocaine Addiction. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2011; 98:367-400. [DOI: 10.1016/b978-0-12-385506-0.00009-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
|
180
|
Ghitza UE, Zhai H, Wu P, Airavaara M, Shaham Y, Lu L. Role of BDNF and GDNF in drug reward and relapse: a review. Neurosci Biobehav Rev 2010; 35:157-71. [PMID: 19914287 PMCID: PMC2891859 DOI: 10.1016/j.neubiorev.2009.11.009] [Citation(s) in RCA: 162] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2009] [Revised: 11/09/2009] [Accepted: 11/10/2009] [Indexed: 11/23/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) are neurotrophic factors that are critical for the growth, survival, and differentiation of developing neurons. These neurotrophic factors also play important roles in the survival and function of adult neurons, learning and memory, and synaptic plasticity. Since the mid-1990s, investigators have studied the role of BDNF and GDNF in the behavioral effects of abused drugs and in the neuroadaptations induced by repeated exposure to drugs in the mesocorticolimbic dopamine system. Here, we review rodent studies on the role of BDNF and GDNF in drug reward, as assessed in the drug self-administration and the conditioned place preference procedures, and in drug relapse, as assessed in extinction and reinstatement procedures. Our main conclusion is that whether BDNF or GDNF would facilitate or inhibit drug-taking behaviors depends on the drug type, the brain site, the addiction phase (initiation, maintenance, or abstinence/relapse), and the time interval between site-specific BDNF or GDNF injections and the reward- and relapse-related behavioral assessments.
Collapse
Affiliation(s)
- Udi E. Ghitza
- Center for the Clinical Trials Network, NIDA, NIH, Bethesda, MD, USA
| | - Haifeng Zhai
- National Institute on Drug Dependence, Peking University, Beijing, China
| | - Ping Wu
- National Institute on Drug Dependence, Peking University, Beijing, China
| | | | - Yavin Shaham
- Intramural Research Program, NIDA, NIH, Baltimore, MD, USA
| | - Lin Lu
- National Institute on Drug Dependence, Peking University, Beijing, China
| |
Collapse
|
181
|
Warner-Schmidt JL, Chen EY, Zhang X, Marshall JJ, Morozov A, Svenningsson P, Greengard P. A role for p11 in the antidepressant action of brain-derived neurotrophic factor. Biol Psychiatry 2010; 68:528-35. [PMID: 20591415 PMCID: PMC2929288 DOI: 10.1016/j.biopsych.2010.04.029] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2010] [Revised: 04/19/2010] [Accepted: 04/30/2010] [Indexed: 10/19/2022]
Abstract
BACKGROUND The protein p11 (also called S100A10) is downregulated in human and rodent depressive-like states. Considerable experimental evidence also implicates p11 in the mechanism of action of antidepressant drugs and electroconvulsive seizures, in part due to its interaction with specific serotonin receptors. Brain-derived neurotrophic factor (BDNF) has been linked to the therapeutic activity of antidepressants in rodent models and humans. In the current study, we investigated whether BDNF regulates p11 in vitro and in vivo. METHODS We utilized primary neuronal cultures, in vivo analyses of transgenic mice, and behavioral techniques to assess the effects of BDNF on p11. RESULTS Results indicate that BDNF stimulates p11 expression through tropomyosin-related kinase B (trkB) receptors and via the mitogen-activated protein kinase signaling pathway. Brain-derived neurotrophic factor-induced changes in p11 in vivo correlate with changes in ligand binding to the 5-hydroxytryptamine receptor 1B, the subcellular localization of which is known to be regulated by p11. Behavioral studies demonstrate that p11 knockout mice are insensitive to the antidepressant actions of BDNF. CONCLUSIONS Taken together, our data demonstrate that p11 levels are regulated by BDNF in vitro and in vivo and that the antidepressant-like effect of BDNF in two well-established behavioral models requires p11. These data support a role for p11 in the antidepressant activity of neurotrophins.
Collapse
Affiliation(s)
| | - Emily Y. Chen
- Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York, NY
| | - Xiaoqun Zhang
- Center for Molecular Medicine, Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden
| | - John J. Marshall
- Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York, NY
| | - Alexei Morozov
- Unit on Behavioral Genetics, Laboratory of Molecular Pathophysiology, National Institute of Mental Health, Bethesda, Maryland
| | - Per Svenningsson
- Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York, NY,Center for Molecular Medicine, Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden
| | - Paul Greengard
- Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York, NY
| |
Collapse
|
182
|
MeCP2 controls BDNF expression and cocaine intake through homeostatic interactions with microRNA-212. Nat Neurosci 2010; 13:1120-7. [PMID: 20711185 PMCID: PMC2928848 DOI: 10.1038/nn.2615] [Citation(s) in RCA: 342] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2010] [Accepted: 07/05/2010] [Indexed: 12/14/2022]
Abstract
The X-linked transcriptional repressor methyl CpG binding protein 2 (MeCP2), known for its role in the neurodevelopmental disorder Rett syndrome, is emerging as an important regulator of neuroplasticity in postmitotic neurons. Cocaine addiction is commonly viewed as a disorder of neuroplasticity, but the potential involvement of MeCP2 has not been explored. Here we identify a key role for MeCP2 in the dorsal striatum in the escalating cocaine intake seen in rats with extended access to the drug, a process that mimics the increasingly uncontrolled cocaine use seen in addicted humans. MeCP2 regulates cocaine intake through homeostatic interactions with microRNA-212 (miR-212) to control the effects of cocaine on striatal brain-derived neurotrophic factor (BDNF) levels. These data suggest that homeostatic interactions between MeCP2 and miR-212 in dorsal striatum may be important in regulating vulnerability to cocaine addiction.
Collapse
|
183
|
Persistent gene expression changes in ventral tegmental area of adolescent but not adult rats in response to chronic nicotine. Neuroscience 2010; 170:503-13. [PMID: 20633606 DOI: 10.1016/j.neuroscience.2010.06.071] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2010] [Revised: 06/18/2010] [Accepted: 06/25/2010] [Indexed: 01/20/2023]
Abstract
Because adolescent brains are undergoing extensive developmental changes, they may be uniquely sensitive to effects of addictive drugs like nicotine. We exposed adolescent and adult rats to nicotine infusion for two weeks, and then used whole genome microarray analysis to determine effects on gene expression in the ventral tegmental area. We examined brains immediately after two weeks of nicotine or saline, and also four weeks after termination of nicotine exposure. After identifying genes with a significant agextreatment interaction, we employed template matching to find specific patterns of expression across age and treatment. Of those genes that were transiently regulated (up- or down-regulated immediately following the end of nicotine treatment, but back to saline baseline 30 days later), two-thirds were specific to adult animals, while only 30% were specific to adolescents and 4% were shared across the two ages. In contrast, significant genes that were persistently regulated (altered following nicotine treatment and still altered 30 days later) were more likely (59%) to be adolescent, with only 32% in adults and 8% shared. The greatest number of significant genes was late-regulated (no change immediately after nicotine, but regulated 30 days later). Again, most were in adolescents (54%), compared to adults (10%) or shared (36%). Pathway analysis revealed that adolescent-specific genes were over-represented in several biological functions and canonical pathways, including nervous system development and function and long-term potentiation. Furthermore, adolescent-specific genes formed extensive interaction networks, unlike those specific for adults or shared. This age-specific expression pattern may relate to the heightened vulnerability of adolescents to the effects of addictive drugs. In particular, the propensity of adolescents to show persistent alterations in gene expression corresponds to the persistence of drug dependence among smokers who began their habit as adolescents. These findings support a model whereby adolescent brains are uniquely vulnerable to long-term changes in gene expression in the brain's reward pathway caused by early exposure to nicotine.
Collapse
|
184
|
|
185
|
TrkB/BDNF-dependent striatal plasticity and behavior in a genetic model of epilepsy: modulation by valproic acid. Neuropsychopharmacology 2010; 35:1531-40. [PMID: 20200504 PMCID: PMC3055450 DOI: 10.1038/npp.2010.23] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In mice lacking the central domain of the presynaptic scaffold Bassoon the occurrence of repeated cortical seizures induces cell-type-specific plasticity changes resulting in a general enhancement of the feedforward inhibition within the striatal microcircuit. Early antiepileptic treatment with valproic acid (VPA) reduces epileptic attacks, inhibits the emergence of pathological form of plasticity in fast-spiking (FS) interneurons and restores physiological striatal synaptic plasticity in medium spiny (MS) neurons. Brain-derived neurotrophic factor (BDNF) is a key factor for the induction and maintenance of synaptic plasticity and it is also implicated in the mechanisms underlying epilepsy-induced adaptive changes. In this study, we explore the possibility that the TrkB/BDNF system is involved in the striatal modifications associated with the Bassoon gene (Bsn) mutation. In epileptic mice abnormal striatum-dependent learning was paralleled by higher TrkB levels and an altered distribution of BDNF. Accordingly, subchronic intrastriatal administration of k252a, an inhibitor of TrkB receptor tyrosine kinase activity, reversed behavioral alterations in Bsn mutant mice. In addition, in vitro manipulations of the TrkB/BDNF complex by k252a, prevented the emergence of pathological plasticity in FS interneurons. Chronic treatment with VPA, by reducing seizures, was able to rebalance TrkB to control levels favoring a physiological redistribution of BDNF between MS neurons and FS interneurons with a concomitant recovery of striatal plasticity. Our results provide the first indication that BDNF is involved in determining the striatal alterations occurring in the early-onset epileptic syndrome associated with the absence of presynaptic protein Bassoon.
Collapse
|
186
|
Numakawa T, Yokomaku D, Richards M, Hori H, Adachi N, Kunugi H. Functional interactions between steroid hormones and neurotrophin BDNF. World J Biol Chem 2010; 1:133-43. [PMID: 21540998 PMCID: PMC3083963 DOI: 10.4331/wjbc.v1.i5.133] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Revised: 05/20/2010] [Accepted: 05/24/2010] [Indexed: 02/05/2023] Open
Abstract
Brain-derived neurotrophic factor (BDNF), a critical neurotrophin, regulates many neuronal aspects including cell differentiation, cell survival, neurotransmission, and synaptic plasticity in the central nervous system (CNS). Though BDNF has two types of receptors, high affinity tropomyosin-related kinase (Trk)B and low affinity p75 receptors, BDNF positively exerts its biological effects on neurons via activation of TrkB and of resultant intracellular signaling cascades including mitogen-activated protein kinase/extracellular signal-regulated protein kinase, phospholipase Cγ, and phosphoinositide 3-kinase pathways. Notably, it is possible that alteration in the expression and/or function of BDNF in the CNS is involved in the pathophysiology of various brain diseases such as stroke, Parkinson’s disease, Alzheimer’s disease, and mental disorders. On the other hand, glucocorticoids, stress-induced steroid hormones, also putatively contribute to the pathophysiology of depression. Interestingly, in addition to the reduction in BDNF levels due to increased glucocorticoid exposure, current reports demonstrate possible interactions between glucocorticoids and BDNF-mediated neuronal functions. Other steroid hormones, such as estrogen, are involved in not only sexual differentiation in the brain, but also numerous neuronal events including cell survival and synaptic plasticity. Furthermore, it is well known that estrogen plays a role in the pathophysiology of Parkinson’s disease, Alzheimer’s disease, and mental illness, while serving to regulate BDNF expression and/or function. Here, we present a broad overview of the current knowledge concerning the association between BDNF expression/function and steroid hormones (glucocorticoids and estrogen).
Collapse
Affiliation(s)
- Tadahiro Numakawa
- Tadahiro Numakawa, Misty Richards, Hiroaki Hori, Naoki Adachi, Hiroshi Kunugi, Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, 187-8502, Japan
| | | | | | | | | | | |
Collapse
|
187
|
Russo SJ, Dietz DM, Dumitriu D, Morrison JH, Malenka RC, Nestler EJ. The addicted synapse: mechanisms of synaptic and structural plasticity in nucleus accumbens. Trends Neurosci 2010; 33:267-76. [PMID: 20207024 DOI: 10.1016/j.tins.2010.02.002] [Citation(s) in RCA: 480] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2009] [Revised: 02/03/2010] [Accepted: 02/12/2010] [Indexed: 12/17/2022]
Abstract
Addictive drugs cause persistent restructuring of several neuronal cell types in the limbic regions of brain thought to be responsible for long-term behavioral plasticity driving addiction. Although these structural changes are well documented in nucleus accumbens medium spiny neurons, little is known regarding the underlying molecular mechanisms. Additionally, it remains unclear whether structural plasticity and its synaptic concomitants drive addictive behaviors or whether they reflect homeostatic compensations to the drug not related to addiction per se. Here, we discuss recent paradoxical data, which either support or oppose the hypothesis that drug-induced changes in dendritic spines drive addictive behavior. We define areas where future investigation can provide a more detailed picture of drug-induced synaptic reorganization, including ultrastructural, electrophysiological and behavioral studies.
Collapse
Affiliation(s)
- Scott J Russo
- Fishberg Department of Neuroscience, Mount Sinai School of Medicine, New York, NY 10029-6574, USA.
| | | | | | | | | | | |
Collapse
|
188
|
Crooks KR, Kleven DT, Rodriguiz RM, Wetsel WC, McNamara JO. TrkB signaling is required for behavioral sensitization and conditioned place preference induced by a single injection of cocaine. Neuropharmacology 2010; 58:1067-77. [PMID: 20176040 DOI: 10.1016/j.neuropharm.2010.01.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2008] [Revised: 01/05/2010] [Accepted: 01/26/2010] [Indexed: 10/19/2022]
Abstract
Exogenous brain-derived neurotrophic factor (BDNF) can regulate behavioral sensitization and conditioned place preference (CPP) when animals are exposed to repeated cocaine administration. However, it is unclear whether BDNF signaling through the TrkB receptor can mediate these behavioral responses when animals are given a single cocaine exposure. Because TrkB knockout mice die as neonates, we engineered a transgenic mouse that expressed a dominant negative form of TrkB (dnTrkB) in a conditional and reversible manner. We assessed also activation of endogenous TrkB by quantifying levels of phosphorylated TrkB (p-TrkB) in the nucleus accumbens (NAc). We found that a single exposure to cocaine was sufficient to increase p-TrkB within the NAc 9-12h after administration. Expression of the dnTrkB transgene not only prevented the acute cocaine-induced increase in p-TrkB, but it also prevented behavioral sensitization and CPP following a single cocaine injection. These findings demonstrate that TrkB activation is required both for behavioral sensitization and CPP to a single cocaine exposure. The fact that enhanced TrkB activation is induced within 9h of a single injection of cocaine suggests that inhibition of TrkB signaling commencing hours after cocaine exposure may prevent at least the initial antecedents to the sensitizing and reinforcing effects of this psychostimulant.
Collapse
Affiliation(s)
- Kristy R Crooks
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
| | | | | | | | | |
Collapse
|
189
|
Abstract
The hippocampus is a region of the mammalian brain that shows an impressive capacity for structural reorganization. Preexisting neural circuits undergo modifications in dendritic complexity and synapse number, and entirely novel neural connections are formed through the process of neurogenesis. These types of structural change were once thought to be restricted to development. However, it is now generally accepted that the hippocampus remains structurally plastic throughout life. This article reviews structural plasticity in the hippocampus over the lifespan, including how it is investigated experimentally. The modulation of structural plasticity by various experiential factors as well as the possible role it may have in hippocampal functions such as learning and memory, anxiety, and stress regulation are also considered. Although significant progress has been made in many of these areas, we highlight some of the outstanding issues that remain.
Collapse
Affiliation(s)
- Benedetta Leuner
- Department of Psychology, Neuroscience Institute, Princeton University, Princeton, New Jersey 08544, USA
| | | |
Collapse
|
190
|
Winrow CJ, Tanis KQ, Reiss DR, Rigby AM, Uslaner JM, Uebele VN, Doran SM, Fox SV, Garson SL, Gotter AL, Levine DM, Roecker AJ, Coleman PJ, Koblan KS, Renger JJ. Orexin receptor antagonism prevents transcriptional and behavioral plasticity resulting from stimulant exposure. Neuropharmacology 2010; 58:185-94. [DOI: 10.1016/j.neuropharm.2009.07.008] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2009] [Revised: 07/02/2009] [Accepted: 07/03/2009] [Indexed: 12/20/2022]
|
191
|
Abstract
We previously found that brain-derived neurotrophic factor (BDNF)-haplodeficient mice exhibit greater ethanol-induced place preference and psychomotor sensitization, and greater ethanol consumption after deprivation, than control mice. We further observed that, in mice, voluntary ethanol intake increases BDNF expression in the dorsal striatum (DS). Here, we determined whether BDNF within the DS regulates ethanol self-administration in Long-Evans rats trained to self-administer a 10% ethanol solution. We observed a greater increase in BDNF expression after ethanol self-administration in the dorsolateral striatum (DLS) than in the dorsomedial striatum (DMS). We further found that downregulation of endogenous BDNF using viral-mediated siRNA in the DLS, but not in the DMS, significantly increased ethanol self-administration. Infusion of exogenous BDNF (0.25 microg/microl/side into the DMS; 0.25 and 0.75 microg/microl/side into the DLS) attenuated responding for ethanol when infused 3 h before the beginning of the self-administration session. Although the decrease in ethanol intake was similar in the DLS and DMS, BDNF infused in the DLS, but not in the DMS, induced an early termination of the drinking episode. Furthermore, the action of BDNF in the DLS was specific for ethanol, as infusion of the neurotrophic factor in the DMS, but not DLS, resulted in a reduction of sucrose intake. Together, these findings demonstrate that the BDNF pathway within the DLS controls the level of ethanol self-administration. Importantly, our results suggest that an endogenous signaling pathway within the same brain region that mediates drug-taking behavior also plays a critical role in gating the level of ethanol intake.
Collapse
|
192
|
|
193
|
New insights in the biology of BDNF synthesis and release: implications in CNS function. J Neurosci 2009; 29:12764-7. [PMID: 19828787 DOI: 10.1523/jneurosci.3566-09.2009] [Citation(s) in RCA: 450] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
BDNF has pleiotropic effects on neuronal development and synaptic plasticity that underlie circuit formation and cognitive function. Recent breakthroughs reveal that neuronal activity regulates BDNF cell biology, including Bdnf transcription, dendritic targeting and trafficking of BDNF mRNA and protein, and secretion and extracellular conversion of proBDNF to mature BDNF. Defects in these mechanisms contribute differentially to cognitive dysfunction and anxiety-like behaviors. Here we review recent studies, presented at a symposium at Neuroscience 2009, that describe regulatory mechanisms that permit rapid and dynamic refinement of BDNF actions in neurons.
Collapse
|
194
|
Gregus AM, Tropea TF, Wang Y, Hauck SCR, Costa ACS, Rajadhyaksha AM, Inturrisi CE. Deletion of the GluR5 subunit of kainate receptors affects cocaine sensitivity and preference. Neurosci Lett 2009; 468:186-9. [PMID: 19878705 DOI: 10.1016/j.neulet.2009.10.071] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2009] [Revised: 08/29/2009] [Accepted: 10/22/2009] [Indexed: 01/22/2023]
Abstract
We have demonstrated previously that mice expressing a constitutive deletion of the kainate receptor subunit GluR5 (GluR5 KO) do not differ from wildtype (WT) littermates of a congenic C57BL/6 background with regard to both the development of morphine physical dependence as measured by naloxone-precipitated withdrawal signs and to morphine reward as revealed by the expression of conditioned place preference (CPP). However, unlike WT, GluR5 KO mice fail to develop antinociceptive tolerance following repeated systemic morphine administration. In this report, we examined the impact of GluR5 deletion on cocaine-mediated CPP and locomotor sensitization. Expression of CPP was evident in WT mice following repeated daily administration of 20mg/kg (but not 10mg/kg) i.p. cocaine. Interestingly, GluR5 KO mice exhibited enhanced cocaine preference as compared with WT mice at both 10 and 20mg/kg doses. In addition, while GluR5 KO mice did not differ from WT with respect to baseline locomotor activity, mutant mice demonstrated increased locomotor hyperactivity versus WT mice after repeated injection of 15mg/kg i.p. cocaine. Collectively, these data indicate that GluR5 appears to negatively modulate some psychostimulant and rewarding properties of cocaine, as demonstrated by heightened sensitization and salience in mutant mice.
Collapse
Affiliation(s)
- Ann M Gregus
- Department of Pharmacology, Weill Cornell Medical College, New York, NY 10065, USA
| | | | | | | | | | | | | |
Collapse
|
195
|
Abstract
Addictive drugs hijack the human brain's 'reward' systems. A zebrafish model of addiction has recently been used to query changes in gene expression during this process.
Collapse
Affiliation(s)
- Jean Lud Cadet
- Molecular Neuropsychiatry Branch, National Institute on Drug Abuse/IRP, NIH Biomedical Research Center, 251 Bayview Blvd, Baltimore, MD 21224, USA.
| |
Collapse
|
196
|
Wheeler JM, Reed C, Burkhart-Kasch S, Li N, Cunningham CL, Janowsky A, Franken FH, Wiren KM, Hashimoto JG, Scibelli AC, Phillips TJ. Genetically correlated effects of selective breeding for high and low methamphetamine consumption. GENES BRAIN AND BEHAVIOR 2009; 8:758-71. [PMID: 19689456 DOI: 10.1111/j.1601-183x.2009.00522.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Improved prevention and treatment of drug addiction will require deeper understanding of genetic factors contributing to susceptibility to excessive drug use. Intravenous operant self-administration methods have greatly advanced understanding of behavioral traits related to addiction. However, these methods are not suitable for large-scale genetic experiments in mice. Selective breeding of mice can aggregate 'addiction alleles' in a model that has the potential to identify coordinated effects of multiple genes. We produced mouse lines that orally self-administer high (MAHDR) or low (MALDR) amounts of methamphetamine, representing the first demonstration of selective breeding for self-administration of any psychostimulant drug. Conditioned place preference and taste aversion results indicate that MAHDR mice are relatively more sensitive to the rewarding effects and less sensitive to the aversive effects of methamphetamine, compared to MALDR mice. These results validate the oral route of self-administration for investigation of the motivational effects of methamphetamine and provide a viable alternative to intravenous self-administration procedures. Gene expression results for a subset of genes relevant to addiction-related processes suggest differential regulation by methamphetamine of apoptosis and immune pathways in the nucleus accumbens of MAHDR and MALDR mice. In each line, methamphetamine reduced an allostatic state by bringing gene expression back toward 'normal' levels. Genes differentially expressed in the drug-naï ve state, including Slc6a4 (serotonin transporter), Htr3a (serotonin receptor 3A), Rela [nuclear factor kappaB (NFkappaB)] and Fos (cFos), represent candidates whose expression levels may predict methamphetamine consumption and susceptibility to methamphetamine reward and aversion.
Collapse
Affiliation(s)
- J M Wheeler
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
197
|
Fumagalli F, Caffino L, Racagni G, Riva MA. Repeated stress prevents cocaine-induced activation of BDNF signaling in rat prefrontal cortex. Eur Neuropsychopharmacol 2009; 19:402-8. [PMID: 19223270 DOI: 10.1016/j.euroneuro.2009.01.003] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2008] [Revised: 12/19/2008] [Accepted: 01/13/2009] [Indexed: 11/28/2022]
Abstract
In this report we provide evidence that repeated stress prevents cocaine-induced activation of BDNF expression and signaling in rat prefrontal cortex. A single injection of cocaine up-regulates BDNF expression in sham (i.e. unstressed) rats but not in repeatedly stressed rats. Similarly, the expression as well as trafficking of the high affinity BDNF receptor trkB promoted by the psychostimulant is impaired in chronically-stressed rats challenged with cocaine. Moreover, among the different intracellular signaling pathways that can be activated by the neurotrophin, i.e. ERK1/2-, Akt- and PLCgamma-pathway, we found that cocaine is able to selectively activate the ERK1/2 pathway in sham animals, but not in rats exposed to repeated stress. Notably, such changes take place in chronically-stressed animals although they still retain the ability to increase neuronal activity as measured by the enhancement of Arc gene expression. In summary, we have demonstrated that stress globally interferes with BDNF-mediated signaling responses to cocaine challenge, providing key insights into the molecular basis of stress-cocaine interaction and indicating the critical role of the prefrontal cortex in mediating such interaction.
Collapse
Affiliation(s)
- Fabio Fumagalli
- Center of Neuropharmacology, Department of Pharmacological Sciences, University of Milan, Via Balzaretti 9, 20133 Milan, Italy.
| | | | | | | |
Collapse
|
198
|
Fumagalli F, Pasini M, Frasca A, Drago F, Racagni G, Riva MA. Prenatal stress alters glutamatergic system responsiveness in adult rat prefrontal cortex. J Neurochem 2009; 109:1733-44. [DOI: 10.1111/j.1471-4159.2009.06088.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
|
199
|
Faccidomo S, Besheer J, Stanford PC, Hodge CW. Increased operant responding for ethanol in male C57BL/6J mice: specific regulation by the ERK1/2, but not JNK, MAP kinase pathway. Psychopharmacology (Berl) 2009; 204:135-47. [PMID: 19125235 PMCID: PMC2845162 DOI: 10.1007/s00213-008-1444-9] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2008] [Accepted: 12/16/2008] [Indexed: 11/30/2022]
Abstract
RATIONALE Extracellular signal-regulated protein kinase (ERK(1/2)) is a member of the mitogen-activated protein kinase (MAPK) signaling pathway and a key molecular target for ethanol (EtOH) and other drugs of abuse. OBJECTIVE The aim of the study was to assess the role of two MAPK pathways, ERK(1/2) and c-Jun N-terminal kinase (JNK), on the modulation of EtOH and sucrose self-administration. MATERIALS AND METHODS C57BL/6J mice were trained to lever press on a fixed-ratio 4 schedule with 9% EtOH/2% sucrose, or 2% sucrose, as the reinforcer. In experiments 1 and 2, mice were injected with the MEK(1/2) inhibitor SL 327 (0-100 mg/kg) and the JNK inhibitor AS 6012452 (0-56 mg/kg) prior to self-administration. In experiment 3, SL 327 (0-100 mg/kg) was administered prior to performance on a progressive ratio (PR) schedule of EtOH reinforcement. In experiment 4, SL 327 and AS 601245 were injected 2 h before a locomotor test. RESULTS SL 327 (30 mg/kg) significantly increased EtOH self-administration without affecting locomotion. Higher doses of SL 327 and AS 601245 reduced EtOH-reinforced responding and locomotor activity. Reductions of both ligands on sucrose self-administration were due to decreases in motor activity. SL 327 pretreatment had no effect on PR responding. CONCLUSIONS ERK(1/2) activity is more directly involved in modulating the reinforcing properties of EtOH than JNK activity due to its selective potentiation of EtOH-reinforced responding. The specificity of this effect to EtOH self-administration, rather than sucrose self-administration, suggests that the mechanism by which ERK(1/2) increases EtOH-reinforced responding does not generalize to all reinforcing solutions and is not due to increased motivation to consume EtOH.
Collapse
Affiliation(s)
- Sara Faccidomo
- Department of Psychiatry, Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | | | | | | |
Collapse
|
200
|
Abstract
Although chronic cocaine-induced changes in dendritic spines on nucleus accumbens (NAc) neurons have been correlated with behavioral sensitization, the molecular pathways governing these structural changes, and their resulting behavioral effects, are poorly understood. The transcription factor, nuclear factor kappa B (NFkappaB), is rapidly activated by diverse stimuli and regulates expression of many genes known to maintain cell structure. Therefore, we evaluated the role of NFkappaB in regulating cocaine-induced dendritic spine changes on medium spiny neurons of the NAc and the rewarding effects of cocaine. We show that chronic cocaine induces NFkappaB-dependent transcription in the NAc of NFkappaB-Lac transgenic mice. This induction of NFkappaB activity is accompanied by increased expression of several NFkappaB genes, the promoters of which show chromatin modifications after chronic cocaine exposure consistent with their transcriptional activation. To study the functional significance of this induction, we used viral-mediated gene transfer to express either a constitutively active or dominant-negative mutant of Inhibitor of kappa B kinase (IKKca or IKKdn), which normally activates NFkappaB signaling, in the NAc. We found that activation of NFkappaB by IKKca increases the number of dendritic spines on NAc neurons, whereas inhibition of NFkappaB by IKKdn decreases basal dendritic spine number and blocks the increase in dendritic spines after chronic cocaine. Moreover, inhibition of NFkappaB blocks the rewarding effects of cocaine and the ability of previous cocaine exposure to increase an animal's preference for cocaine. Together, these studies establish a direct role for NFkappaB pathways in the NAc to regulate structural and behavioral plasticity to cocaine.
Collapse
|