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Ramos A, Granzotto N, Kremer R, Boeder AM, de Araújo JFP, Pereira AG, Izídio GS. Hunting for Genes Underlying Emotionality in the Laboratory Rat: Maps, Tools and Traps. Curr Neuropharmacol 2023; 21:1840-1863. [PMID: 36056863 PMCID: PMC10514530 DOI: 10.2174/1570159x20666220901154034] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 06/13/2022] [Accepted: 07/28/2022] [Indexed: 11/22/2022] Open
Abstract
Scientists have systematically investigated the hereditary bases of behaviors since the 19th century, moved by either evolutionary questions or clinically-motivated purposes. The pioneer studies on the genetic selection of laboratory animals had already indicated, one hundred years ago, the immense complexity of analyzing behaviors that were influenced by a large number of small-effect genes and an incalculable amount of environmental factors. Merging Mendelian, quantitative and molecular approaches in the 1990s made it possible to map specific rodent behaviors to known chromosome regions. From that point on, Quantitative Trait Locus (QTL) analyses coupled with behavioral and molecular techniques, which involved in vivo isolation of relevant blocks of genes, opened new avenues for gene mapping and characterization. This review examines the QTL strategy applied to the behavioral study of emotionality, with a focus on the laboratory rat. We discuss the challenges, advances and limitations of the search for Quantitative Trait Genes (QTG) playing a role in regulating emotionality. For the past 25 years, we have marched the long journey from emotionality-related behaviors to genes. In this context, our experiences are used to illustrate why and how one should move forward in the molecular understanding of complex psychiatric illnesses. The promise of exploring genetic links between immunological and emotional responses are also discussed. New strategies based on humans, rodents and other animals (such as zebrafish) are also acknowledged, as they are likely to allow substantial progress to be made in the near future.
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Affiliation(s)
- André Ramos
- Behavior Genetics Laboratory, Department of Cell Biology, Embryology and Genetics, Center of Biological Sciences, Federal University of Santa Catarina, Florianopolis, Brazil
| | - Natalli Granzotto
- Behavior Genetics Laboratory, Department of Cell Biology, Embryology and Genetics, Center of Biological Sciences, Federal University of Santa Catarina, Florianopolis, Brazil
- Graduate Program of Pharmacology, Center of Biological Sciences, Federal University of Santa Catarina, Florianopolis, Brazil
| | - Rafael Kremer
- Behavior Genetics Laboratory, Department of Cell Biology, Embryology and Genetics, Center of Biological Sciences, Federal University of Santa Catarina, Florianopolis, Brazil
- Graduate Program of Developmental and Cellular Biology, Center of Biological Sciences, Federal University of Santa Catarina, Florianopolis, Brazil
| | - Ariela Maína Boeder
- Behavior Genetics Laboratory, Department of Cell Biology, Embryology and Genetics, Center of Biological Sciences, Federal University of Santa Catarina, Florianopolis, Brazil
- Graduate Program of Pharmacology, Center of Biological Sciences, Federal University of Santa Catarina, Florianopolis, Brazil
| | - Julia Fernandez Puñal de Araújo
- Behavior Genetics Laboratory, Department of Cell Biology, Embryology and Genetics, Center of Biological Sciences, Federal University of Santa Catarina, Florianopolis, Brazil
- Graduate Program of Developmental and Cellular Biology, Center of Biological Sciences, Federal University of Santa Catarina, Florianopolis, Brazil
| | - Aline Guimarães Pereira
- Behavior Genetics Laboratory, Department of Cell Biology, Embryology and Genetics, Center of Biological Sciences, Federal University of Santa Catarina, Florianopolis, Brazil
- Graduate Program of Developmental and Cellular Biology, Center of Biological Sciences, Federal University of Santa Catarina, Florianopolis, Brazil
| | - Geison Souza Izídio
- Behavior Genetics Laboratory, Department of Cell Biology, Embryology and Genetics, Center of Biological Sciences, Federal University of Santa Catarina, Florianopolis, Brazil
- Graduate Program of Pharmacology, Center of Biological Sciences, Federal University of Santa Catarina, Florianopolis, Brazil
- Graduate Program of Developmental and Cellular Biology, Center of Biological Sciences, Federal University of Santa Catarina, Florianopolis, Brazil
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Single-nucleus transcriptome analysis reveals cell-type-specific molecular signatures across reward circuitry in the human brain. Neuron 2021; 109:3088-3103.e5. [PMID: 34582785 DOI: 10.1016/j.neuron.2021.09.001] [Citation(s) in RCA: 84] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 08/02/2021] [Accepted: 08/31/2021] [Indexed: 11/21/2022]
Abstract
Single-cell gene expression technologies are powerful tools to study cell types in the human brain, but efforts have largely focused on cortical brain regions. We therefore created a single-nucleus RNA-sequencing resource of 70,615 high-quality nuclei to generate a molecular taxonomy of cell types across five human brain regions that serve as key nodes of the human brain reward circuitry: nucleus accumbens, amygdala, subgenual anterior cingulate cortex, hippocampus, and dorsolateral prefrontal cortex. We first identified novel subpopulations of interneurons and medium spiny neurons (MSNs) in the nucleus accumbens and further characterized robust GABAergic inhibitory cell populations in the amygdala. Joint analyses across the 107 reported cell classes revealed cell-type substructure and unique patterns of transcriptomic dynamics. We identified discrete subpopulations of D1- and D2-expressing MSNs in the nucleus accumbens to which we mapped cell-type-specific enrichment for genetic risk associated with both psychiatric disease and addiction.
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Szpirer C. Rat models of human diseases and related phenotypes: a systematic inventory of the causative genes. J Biomed Sci 2020; 27:84. [PMID: 32741357 PMCID: PMC7395987 DOI: 10.1186/s12929-020-00673-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 07/09/2020] [Indexed: 12/13/2022] Open
Abstract
The laboratory rat has been used for a long time as the model of choice in several biomedical disciplines. Numerous inbred strains have been isolated, displaying a wide range of phenotypes and providing many models of human traits and diseases. Rat genome mapping and genomics was considerably developed in the last decades. The availability of these resources has stimulated numerous studies aimed at discovering causal disease genes by positional identification. Numerous rat genes have now been identified that underlie monogenic or complex diseases and remarkably, these results have been translated to the human in a significant proportion of cases, leading to the identification of novel human disease susceptibility genes, helping in studying the mechanisms underlying the pathological abnormalities and also suggesting new therapeutic approaches. In addition, reverse genetic tools have been developed. Several genome-editing methods were introduced to generate targeted mutations in genes the function of which could be clarified in this manner [generally these are knockout mutations]. Furthermore, even when the human gene causing a disease had been identified without resorting to a rat model, mutated rat strains (in particular KO strains) were created to analyze the gene function and the disease pathogenesis. Today, over 350 rat genes have been identified as underlying diseases or playing a key role in critical biological processes that are altered in diseases, thereby providing a rich resource of disease models. This article is an update of the progress made in this research and provides the reader with an inventory of these disease genes, a significant number of which have similar effects in rat and humans.
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Affiliation(s)
- Claude Szpirer
- Université Libre de Bruxelles, B-6041, Gosselies, Belgium.
- , Waterloo, Belgium.
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Carboni L, Romoli B, Bate ST, Romualdi P, Zoli M. Increased expression of CRF and CRF-receptors in dorsal striatum, hippocampus, and prefrontal cortex after the development of nicotine sensitization in rats. Drug Alcohol Depend 2018; 189:12-20. [PMID: 29857328 DOI: 10.1016/j.drugalcdep.2018.04.027] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 04/13/2018] [Accepted: 04/16/2018] [Indexed: 12/21/2022]
Abstract
BACKGROUND Nicotine addiction supports tobacco smoking, a main preventable cause of disease and death in Western countries. It develops through long-term neuroadaptations in the brain reward circuit by modulating intracellular pathways and regulating gene expression. This study assesses the regional expression of the transcripts of the CRF transmission in a nicotine sensitization model, since it is hypothesised that the molecular neuroadaptations that mediate the development of sensitization contribute to the development of addiction. METHODS Rats received intraperitoneal nicotine administrations (0.4 mg/kg) once daily for either 1 day or over 5 days. Locomotor activity was assessed to evaluate the development of sensitization. The mRNA expression of CRF and CRF1 and CRF2 receptors was measured by qPCR in the ventral mesencephalon, ventral striatum, dorsal striatum (DS), prefrontal cortex (PFCx), and hippocampus (Hip). RESULTS Acute nicotine administration increased locomotor activity in rats. In the sub-chronic group, locomotor activity progressively increased and reached a clear sensitization. Significant effects of sensitization on CRF mRNA levels were detected in the DS (increasing effect). Significantly higher CRF1 and CRF2 receptor levels after sensitization were detected in the Hip. Additionally, CRF2 receptor levels were augmented by sensitization in the PFCx, and treatment and time-induced increases were detected in the DS. Nicotine treatment effects were observed on CRF1R levels in the DS. CONCLUSIONS This study suggests that the CRF transmission, in addition to its role in increasing withdrawal-related anxiety, may be involved in the development of nicotine-habituated behaviours through reduced control of impulses and the aberrant memory plasticity characterising addiction.
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Affiliation(s)
- Lucia Carboni
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum University of Bologna, Via Irnerio 48, 40126 Bologna, Italy.
| | - Benedetto Romoli
- Department of Biomedical, Metabolic and Neural Sciences, Center for Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, Via Giuseppe Campi 287, 41125 Modena, Italy; Department of Psychiatry, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA
| | - Simon T Bate
- Statistical Sciences, GlaxoSmithKline, 980 Great West Rd, Brentford, Middlesex, TW8 9GS, UK
| | - Patrizia Romualdi
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum University of Bologna, Via Irnerio 48, 40126 Bologna, Italy
| | - Michele Zoli
- Department of Biomedical, Metabolic and Neural Sciences, Center for Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, Via Giuseppe Campi 287, 41125 Modena, Italy
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Corticotropin-Releasing Factor (CRF) Neurocircuitry and Neuropharmacology in Alcohol Drinking. Handb Exp Pharmacol 2018; 248:435-471. [PMID: 29374836 DOI: 10.1007/164_2017_86] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Alcohol use is pervasive in the United States. In the transition from nonhazardous drinking to hazardous drinking and alcohol use disorder, neuroadaptations occur within brain reward and brain stress systems. One brain signaling system that has received much attention in animal models of excessive alcohol drinking and alcohol dependence is corticotropin-releasing factor (CRF). The CRF system is composed of CRF, the urocortins, CRF-binding protein, and two receptors - CRF type 1 and CRF type 2. This review summarizes how acute, binge, and chronic alcohol dysregulates CRF signaling in hypothalamic and extra-hypothalamic brain regions and how this dysregulation may contribute to changes in alcohol reinforcement, excessive alcohol consumption, symptoms of negative affect during withdrawal, and alcohol relapse. In addition, it summarizes clinical work examining CRF type 1 receptor antagonists in humans and discusses why the brain CRF system is still relevant in alcohol research.
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Varodayan FP, Correia D, Kirson D, Khom S, Oleata CS, Luu G, Schweitzer P, Roberto M. CRF modulates glutamate transmission in the central amygdala of naïve and ethanol-dependent rats. Neuropharmacology 2017; 125:418-428. [PMID: 28807676 DOI: 10.1016/j.neuropharm.2017.08.009] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 07/21/2017] [Accepted: 08/09/2017] [Indexed: 11/15/2022]
Abstract
Corticotropin-releasing factor (CRF) signaling in the central nucleus of the amygdala (CeA) is hypothesized to drive the development of alcohol dependence, as it regulates ethanol intake and several anxiogenic behaviors linked to withdrawal. Excitatory glutamatergic neurotransmission contributes to alcohol reinforcement, tolerance and dependence. Therefore, in this study we used in vitro slice electrophysiology to investigate the effects of CRF and its receptor subtype (CRF1 and CRF2) antagonists on both evoked and spontaneous action potential-independent glutamatergic transmission in the CeA of naive and ethanol-dependent Sprague-Dawley rats. We found that CRF (25-200 nM) concentration-dependently diminished evoked compound excitatory postsynaptic potentials (EPSPs), but increased miniature excitatory postsynaptic current (mEPSC) frequencies similarly in CeA neurons of both naïve and ethanol-dependent rats, indicating reduced evoked glutamatergic responses and enhanced vesicular glutamate release, respectively. This CRF-induced vesicular glutamate release was prevented by the CRF1/2 antagonist (Astressin B) and the CRF1 antagonist (R121919), but not by the CRF2 antagonist (Astressin 2B). Similarly, CRF's effects on evoked glutamatergic responses were completely blocked by CRF1 antagonism, but only slightly decreased in the presence of the CRF2 antagonist. Moreover, CRF1 antagonism reveals a tonic facilitation of vesicular glutamate, whereas the CRF2 antagonism revealed a tonic inhibition of vesicular glutamate release. Collectively our data show that CRF primarily acts at presynaptic CRF1 to produce opposite effects on CeA evoked and spontaneous glutamate release and that the CRF system modulates CeA glutamatergic synapses throughout the development of alcohol dependence.
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Affiliation(s)
| | - Diego Correia
- Department of Neuroscience, The Scripps Research Institute, La Jolla, CA, USA; Department of Pharmacology, Universidade Federal do Paraná, Jardim das Américas, Curitiba, Paraná, CEP 81531-990, Brazil
| | - Dean Kirson
- Department of Neuroscience, The Scripps Research Institute, La Jolla, CA, USA
| | - Sophia Khom
- Department of Neuroscience, The Scripps Research Institute, La Jolla, CA, USA
| | | | - George Luu
- Department of Neuroscience, The Scripps Research Institute, La Jolla, CA, USA
| | - Paul Schweitzer
- Department of Neuroscience, The Scripps Research Institute, La Jolla, CA, USA
| | - Marisa Roberto
- Department of Neuroscience, The Scripps Research Institute, La Jolla, CA, USA.
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Analyses of differentially expressed genes after exposure to acute stress, acute ethanol, or a combination of both in mice. Alcohol 2017; 58:139-151. [PMID: 28027852 DOI: 10.1016/j.alcohol.2016.08.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 08/10/2016] [Accepted: 08/10/2016] [Indexed: 12/31/2022]
Abstract
Alcohol abuse is a complex disorder, which is confounded by other factors, including stress. In the present study, we examined gene expression in the hippocampus of BXD recombinant inbred mice after exposure to ethanol (NOE), stress (RSS), and the combination of both (RSE). Mice were given an intraperitoneal (i.p.) injection of 1.8 g/kg ethanol or saline, and subsets of both groups were exposed to acute restraint stress for 15 min or controls. Gene expression in the hippocampus was examined using microarray analysis. Genes that were significantly (p < 0.05, q < 0.1) differentially expressed were further evaluated. Bioinformatic analyses were predominantly performed using tools available at GeneNetwork.org, and included gene ontology, presence of cis-regulation or polymorphisms, phenotype correlations, and principal component analyses. Comparisons of differential gene expression between groups showed little overlap. Gene Ontology demonstrated distinct biological processes in each group with the combined exposure (RSE) being unique from either the ethanol (NOE) or stress (RSS) group, suggesting that the interaction between these variables is mediated through diverse molecular pathways. This supports the hypothesis that exposure to stress alters ethanol-induced gene expression changes and that exposure to alcohol alters stress-induced gene expression changes. Behavior was profiled in all groups following treatment, and many of the differentially expressed genes are correlated with behavioral variation within experimental groups. Interestingly, in each group several genes were correlated with the same phenotype, suggesting that these genes are the potential origins of significant genetic networks. The distinct sets of differentially expressed genes within each group provide the basis for identifying molecular networks that may aid in understanding the complex interactions between stress and ethanol, and potentially provide relevant therapeutic targets. Using Ptp4a1, a candidate gene underlying the quantitative trait locus for several of these phenotypes, and network analyses, we show that a large group of differentially expressed genes in the NOE group are highly interrelated, some of which have previously been linked to alcohol addiction or alcohol-related phenotypes.
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Qiu B, Bell RL, Cao Y, Zhang L, Stewart RB, Graves T, Lumeng L, Yong W, Liang T. Npy deletion in an alcohol non-preferring rat model elicits differential effects on alcohol consumption and body weight. J Genet Genomics 2016; 43:421-30. [PMID: 27461754 PMCID: PMC5055068 DOI: 10.1016/j.jgg.2016.04.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2015] [Revised: 04/21/2016] [Accepted: 04/27/2016] [Indexed: 11/21/2022]
Abstract
Neuropeptide Y (NPY) is widely expressed in the central nervous system and influences many physiological processes. It is located within the rat quantitative trait locus (QTL) for alcohol preference on chromosome 4. Alcohol-nonpreferring (NP) rats consume very little alcohol, but have significantly higher NPY expression in the brain than alcohol-preferring (P) rats. We capitalized on this phenotypic difference by creating an Npy knockout (KO) rat using the inbred NP background to evaluate NPY effects on alcohol consumption. Zinc finger nuclease (ZNF) technology was applied, resulting in a 26-bp deletion in the Npy gene. RT-PCR, Western blotting and immunohistochemistry confirmed the absence of Npy mRNA and protein in KO rats. Alcohol consumption was increased in Npy(+/-) but not Npy(-/-) rats, while Npy(-/-) rats displayed significantly lower body weight when compared to Npy(+/+) rats. In whole brain tissue, expression levels of Npy-related and other alcohol-associated genes, Npy1r, Npy2r, Npy5r, Agrp, Mc3r, Mc4r, Crh and Crh1r, were significantly greater in Npy(-/-) rats, whereas Pomc and Crhr2 expressions were highest in Npy(+/-) rats. These findings suggest that the NPY-system works in close coordination with the melanocortin (MC) and corticotropin-releasing hormone (CRH) systems to modulate alcohol intake and body weight.
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Affiliation(s)
- Bin Qiu
- Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100021, China
| | - Richard L Bell
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Yong Cao
- Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100021, China; Experimental Medicine Center, The First Affiliated Hospital of Sichuan Medical University, Luzhou 646000, China
| | - Lingling Zhang
- Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100021, China
| | - Robert B Stewart
- Department of Psychology, Purdue School of Science, Indiana University-Purdue University of Indianapolis, Indianapolis, IN 46202, USA
| | - Tamara Graves
- Department of Gastroenterology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Lawrence Lumeng
- Department of Gastroenterology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Weidong Yong
- Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100021, China.
| | - Tiebing Liang
- Department of Gastroenterology, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
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Logan RW, Wynne O, Maglakelidze G, Zhang C, O'Connell S, Boyadjieva NI, Sarkar DK. β-Endorphin neuronal transplantation into the hypothalamus alters anxiety-like behaviors in prenatal alcohol-exposed rats and alcohol-non-preferring and alcohol-preferring rats. Alcohol Clin Exp Res 2016; 39:146-57. [PMID: 25623413 DOI: 10.1111/acer.12611] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 10/22/2014] [Indexed: 11/28/2022]
Abstract
BACKGROUND Alcohol exposure has adverse effects on stress physiology and behavioral reactivity. This is suggested to be due, in part, to the effect of alcohol on β-endorphin (β-EP)-producing neurons in the hypothalamus. In response to stress, β-EP normally provides negative feedback to the hypothalamic-pituitary-adrenal axis and interacts with other neurotransmitter systems in the amygdala to regulate behavior. We examined whether β-EP neuronal function in the hypothalamus reduces the corticosterone response to acute stress, attenuates anxiety-like behaviors, and modulates alcohol drinking in rats. METHODS To determine whether β-EP neuronal transplants modulate the stress response, anxiety behavior, and alcohol drinking, we implanted differentiated β-EP neurons into the paraventricular nucleus (PVN) of the hypothalamus of normal, prenatal alcohol-exposed, and alcohol-preferring (P) and alcohol-non-preferring (NP) rats. We then assessed corticosterone levels in response to acute restraint stress and other markers of stress response in the brain and anxiety-like behaviors in the elevated plus maze and open-field assays. RESULTS We showed that β-EP neuronal transplants into the PVN reduced the peripheral corticosterone response to acute stress and attenuated anxiety-like behaviors. Similar transplants completely reduced the hypercorticosterone response and elevated anxiety behaviors in prenatal alcohol-exposed adult rats. Moreover, we showed that β-EP reduced anxiety behavior in P rats with minimal effects on alcohol drinking during and following restraint stress. CONCLUSIONS These data further establish a role of β-EP neurons in the hypothalamus for regulating physiological stress response and anxiety behavior and resemble a potential novel therapy for treating stress-related psychiatric disorders in prenatal alcohol-exposed children and those genetically predisposed to increased alcohol consumption.
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Affiliation(s)
- Ryan W Logan
- Endocrine Program, Rutgers, The State University of New Jersey, New Brunswick, New Jersey; University of Pittsburgh Medical Center, Department of Psychiatry, Translational Neuroscience Program, Pittsburgh, Pennsylvania
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Cipriano AC, Gomes KS, Nunes-de-Souza RL. CRF receptor type 1 (but not type 2) located within the amygdala plays a role in the modulation of anxiety in mice exposed to the elevated plus maze. Horm Behav 2016; 81:59-67. [PMID: 27060334 DOI: 10.1016/j.yhbeh.2016.03.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 03/04/2016] [Accepted: 03/18/2016] [Indexed: 10/22/2022]
Abstract
The amygdala (Amy) is an important center that processes threatening stimuli. Among the neurotransmitters implicated in the control of emotional states, the corticotrophin releasing factor (CRF) is an important modulator, acting at CRF1 and CRF2 receptors. Few studies have investigated the role of CRF and its receptors in the Amy on anxiety in mice. Here, we investigated the effects of intra-Amy (aimed at the basolateral nucleus) injections of CRF (37.5 and 75pmol/0.1μl), urocortin 3 (UCn3, a selective CRF2 agonist; 4, 8, 16 or 24pmol/0.1μl), CP376395 (a selective CRF1 antagonist; 0.375, 0.75 or 1.5nmol/0.1μl), antisauvagine-30 (ASV-30, a selective CRF2 antagonist; 1 or 3nmol/0.1μl) on the behavior of mice exposed to the elevated plus maze (EPM). Both spatiotemporal (e.g., percentage of open-arm entries and percentage of open-arm time; %OE and %OT) and complementary [e.g., frequency of protected and unprotected stretched attend postures (pSAP and uSAP) and head dips (pHD and uHD); frequency and time spent on open arm end exploration (OAEE)] measures were recorded during a 5-min test in the EPM. While intra-Amy injections of CRF decreased %OE, %OT and OAEE, suggesting an anxiogenic-like action, UCn3 (all doses) did not change any behavior. In contrast, injections of CP376395 (0.75nmol) produced an anxiolytic-like effect, by increasing %OT and OAEE and decreasing pSAP and pHD. Neither spatiotemporal nor complementary measures were changed by intra-Amy ASV-30. These results suggest that CRF plays a marked anxiogenic role at CRF1 receptors in the amygdala of mice exposed to the EPM.
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Affiliation(s)
- Ana Cláudia Cipriano
- School of Pharmaceutical Sciences, Univ. Estadual Paulista - UNESP, 14800-903, Araraquara, SP, Brazil; Joint Graduate Program in Physiological Sciences, UFSCar/UNESP, São Carlos, SP 13565-905, Brazil.
| | - Karina Santos Gomes
- School of Pharmaceutical Sciences, Univ. Estadual Paulista - UNESP, 14800-903, Araraquara, SP, Brazil.
| | - Ricardo Luiz Nunes-de-Souza
- School of Pharmaceutical Sciences, Univ. Estadual Paulista - UNESP, 14800-903, Araraquara, SP, Brazil; Joint Graduate Program in Physiological Sciences, UFSCar/UNESP, São Carlos, SP 13565-905, Brazil.
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Bell RL, Hauser S, Rodd ZA, Liang T, Sari Y, McClintick J, Rahman S, Engleman EA. A Genetic Animal Model of Alcoholism for Screening Medications to Treat Addiction. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2016; 126:179-261. [PMID: 27055615 PMCID: PMC4851471 DOI: 10.1016/bs.irn.2016.02.017] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The purpose of this review is to present up-to-date pharmacological, genetic, and behavioral findings from the alcohol-preferring P rat and summarize similar past work. Behaviorally, the focus will be on how the P rat meets criteria put forth for a valid animal model of alcoholism with a highlight on its use as an animal model of polysubstance abuse, including alcohol, nicotine, and psychostimulants. Pharmacologically and genetically, the focus will be on the neurotransmitter and neuropeptide systems that have received the most attention: cholinergic, dopaminergic, GABAergic, glutamatergic, serotonergic, noradrenergic, corticotrophin releasing hormone, opioid, and neuropeptide Y. Herein, we sought to place the P rat's behavioral and neurochemical phenotypes, and to some extent its genotype, in the context of the clinical literature. After reviewing the findings thus far, this chapter discusses future directions for expanding the use of this genetic animal model of alcoholism to identify molecular targets for treating drug addiction in general.
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Affiliation(s)
- R L Bell
- Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, IN, United States.
| | - S Hauser
- Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Z A Rodd
- Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, IN, United States
| | - T Liang
- Indiana University School of Medicine, Indianapolis, IN, United States
| | - Y Sari
- University of Toledo, Toledo, OH, United States
| | - J McClintick
- Center for Medical Genomics, Indiana University School of Medicine, Indianapolis, IN, United States
| | - S Rahman
- Department of Pharmaceutical Sciences, South Dakota State University, Brookings, SD, United States
| | - E A Engleman
- Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, IN, United States
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Phillips TJ, Reed C, Pastor R. Preclinical evidence implicating corticotropin-releasing factor signaling in ethanol consumption and neuroadaptation. GENES BRAIN AND BEHAVIOR 2015; 14:98-135. [PMID: 25565358 DOI: 10.1111/gbb.12189] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 11/22/2014] [Accepted: 11/25/2014] [Indexed: 12/15/2022]
Abstract
The results of many studies support the influence of the corticotropin-releasing factor (CRF) system on ethanol (EtOH) consumption and EtOH-induced neuroadaptations that are critical in the addiction process. This review summarizes the preclinical data in this area after first providing an overview of the components of the CRF system. This complex system involves hypothalamic and extra-hypothalamic mechanisms that play a role in the central and peripheral consequences of stressors, including EtOH and other drugs of abuse. In addition, several endogenous ligands and targets make up this system and show differences in their involvement in EtOH drinking and in the effects of chronic or repeated EtOH treatment. In general, genetic and pharmacological approaches paint a consistent picture of the importance of CRF signaling via type 1 CRF receptors (CRF(1)) in EtOH-induced neuroadaptations that result in higher levels of intake, encourage alcohol seeking during abstinence and alter EtOH sensitivity. Furthermore, genetic findings in rodents, non-human primates and humans have provided some evidence of associations of genetic polymorphisms in CRF-related genes with EtOH drinking, although additional data are needed. These results suggest that CRF(1) antagonists have potential as pharmacotherapeutics for alcohol use disorders. However, given the broad and important role of these receptors in adaptation to environmental and other challenges, full antagonist effects may be too profound and consideration should be given to treatments with modulatory effects.
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Affiliation(s)
- T J Phillips
- VA Portland Health Care System, Portland Alcohol Research Center, Methamphetamine Abuse Research Center, Oregon Health & Science University, Portland, OR, USA; Department of Behavioral Neuroscience, Portland Alcohol Research Center, Methamphetamine Abuse Research Center, Oregon Health & Science University, Portland, OR, USA
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McClintick JN, McBride WJ, Bell RL, Ding ZM, Liu Y, Xuei X, Edenberg HJ. Gene expression changes in serotonin, GABA-A receptors, neuropeptides and ion channels in the dorsal raphe nucleus of adolescent alcohol-preferring (P) rats following binge-like alcohol drinking. Pharmacol Biochem Behav 2014; 129:87-96. [PMID: 25542586 PMCID: PMC4302739 DOI: 10.1016/j.pbb.2014.12.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 12/13/2014] [Accepted: 12/17/2014] [Indexed: 12/31/2022]
Abstract
Alcohol binge-drinking during adolescence is a serious public health concern with long-term consequences. We used RNA sequencing to assess the effects of excessive adolescent ethanol binge-drinking on gene expression in the dorsal raphe nucleus (DRN) of alcohol preferring (P) rats. Repeated binges across adolescence (three 1h sessions across the dark-cycle per day, 5 days per week for 3 weeks starting at 28 days of age; ethanol intakes of 2.5-3 g/kg/session) significantly altered the expression of approximately one-third of the detected genes. Multiple neurotransmitter systems were altered, with the largest changes in the serotonin system (21 of 23 serotonin-related genes showed decreased expression) and GABA-A receptors (8 decreased and 2 increased). Multiple neuropeptide systems were also altered, with changes in the neuropeptide Y and corticotropin-releasing hormone systems similar to those associated with increased drinking and decreased resistance to stress. There was increased expression of 21 of 32 genes for potassium channels. Expression of downstream targets of CREB signaling was increased. There were also changes in expression of genes involved in inflammatory processes, axonal guidance, growth factors, transcription factors, and several intracellular signaling pathways. These widespread changes indicate that excessive binge drinking during adolescence alters the functioning of the DRN and likely its modulation of many regions of the central nervous system, including the mesocorticolimbic system.
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Affiliation(s)
- Jeanette N McClintick
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, United States; Center for Medical Genomics, Indiana University School of Medicine, Indianapolis, IN 46202, United States
| | - William J McBride
- Institute of Psychiatric Research, Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN 46202, United States
| | - Richard L Bell
- Institute of Psychiatric Research, Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN 46202, United States
| | - Zheng-Ming Ding
- Institute of Psychiatric Research, Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN 46202, United States
| | - Yunlong Liu
- Department of Medical & Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, United States
| | - Xiaoling Xuei
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, United States; Center for Medical Genomics, Indiana University School of Medicine, Indianapolis, IN 46202, United States
| | - Howard J Edenberg
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, United States; Center for Medical Genomics, Indiana University School of Medicine, Indianapolis, IN 46202, United States; Department of Medical & Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, United States.
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Medeiros GFD, Corrêa FJ, Corvino ME, Izídio GDS, Ramos A. The Long Way from Complex Phenotypes to Genes: The Story of Rat Chromosome 4 and Its Behavioral Effects. ACTA ACUST UNITED AC 2014. [DOI: 10.4236/wjns.2014.43024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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