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Marti-Prats L, Belin D. Characterization in the rat of the individual tendency to rely on alcohol to cope with distress and the ensuing vulnerability to drink compulsively. Brain Commun 2024; 6:fcae169. [PMID: 38868300 PMCID: PMC11168338 DOI: 10.1093/braincomms/fcae169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 03/12/2024] [Accepted: 05/10/2024] [Indexed: 06/14/2024] Open
Abstract
Only some vulnerable individuals who recreationally drink alcohol eventually develop the compulsive drinking pattern that characterizes alcohol use disorder. A new frontier in biomedical research lies in understanding the neurobehavioural mechanisms of this individual vulnerability, a necessary step towards developing novel effective therapeutic strategies. Translational research has been hindered by the lack of valid, reliable and robust approaches that enable the study of the influence of the reliance on alcohol to cope with stress or self-medicate negative emotional states on the subsequent transition to alcohol use disorder. We have therefore developed a behavioural task in the rat that enables the investigation of the neural and cellular basis of the exacerbation of the vulnerability to develop compulsive alcohol drinking by the use of alcohol to develop an adjunctive, anxiolytic, polydipsic drinking behaviour in a schedule-induced polydipsia procedure. Hence, in our task, alcohol is introduced in the schedule-induced polydipsia context after several weeks of training with water so that rats are exposed to alcohol for the first time in a distressing context and learn to drink alcohol as a coping strategy. Capitalizing on this protocol, we have consistently been able to identify a subpopulation of rats that were unable to learn to cope with negative states by drinking water and relied on alcohol to do so. This maladaptive reliance on alcohol drinking to cope with distress has been shown to be associated with an exacerbation of the subsequent transition to compulsive drinking. Furthermore, these vulnerable rats reached blood alcohol levels comparable to that of intoxication in humans, thereby developing two key features of alcohol use disorder, namely excessive alcohol intake and compulsive drinking. Altogether, this behavioural task provides a novel and unique tool for the investigation of the neurobehavioural mechanisms underlying the exacerbation of the individual vulnerability to developing compulsive alcohol drinking by the use of alcohol as a strategy to cope with distress, and for the evaluation of the efficacy of potential therapeutic strategies in a personalized medicine approach. This procedure, which focuses on an understudied but key factor of the development of alcohol use disorder, may become widely used as it benefits the fields of alcohol, emotion regulation and stress, the interest in which has substantially increased since the evidence of a profound exacerbation of alcohol use and alcohol-related negative consequences by the distress and social isolation engendered by the various measures implemented worldwide in response to the COVID-19 pandemic.
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Affiliation(s)
- Lucia Marti-Prats
- Department of Psychology, CLIC (Cambridge Laboratory for Research on Impulsive/Compulsive Disorders), University of Cambridge, Cambridge CB2 3EB, UK
| | - David Belin
- Department of Psychology, CLIC (Cambridge Laboratory for Research on Impulsive/Compulsive Disorders), University of Cambridge, Cambridge CB2 3EB, UK
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2
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Becker HC, Lopez MF. Animal Models of Excessive Alcohol Consumption in Rodents. Curr Top Behav Neurosci 2024. [PMID: 38340255 DOI: 10.1007/7854_2024_461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2024]
Abstract
The development of animal models that demonstrate excessive levels of alcohol consumption has played an important role in advancing our knowledge about neurobiological underpinnings and environmental circumstances that engender such maladaptive behavior. The use of these preclinical models has also provided valuable opportunities for discovering new and novel therapeutic targets that may be useful in the treatment of alcohol use disorder (AUD). While no single model can fully capture the complexities of AUD, the goal is to develop animal models that closely approximate characteristics of heavy alcohol drinking in humans to enhance their translational value and utility. A variety of experimental approaches have been employed to produce the desired phenotype of interest-robust and reliable excessive levels of alcohol drinking. Here we provide an updated review of five animal models that are commonly used. The models entail procedural manipulations of scheduled access to alcohol (time of day, duration, frequency), periods of time when access to alcohol is withheld, and history of alcohol exposure. Specially, the models involve (a) scheduled access to alcohol, (b) scheduled periods of alcohol deprivation, (c) scheduled intermittent access to alcohol, (d) scheduled-induced polydipsia, and (e) chronic alcohol (dependence) and withdrawal experience. Each of the animal models possesses unique experimental features that engender excessive levels of alcohol consumption. Both advantages and disadvantages of each model are described along with discussion of future work to be considered in developing more optimal models. Ultimately, the validity and utility of these models will lie in their ability to aid in the discovery of new and novel potential therapeutic targets as well as serve as a platform to evaluate treatment strategies that effectively reduce excessive levels of alcohol consumption associated with AUD.
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Affiliation(s)
- Howard C Becker
- Charleston Alcohol Research Center, Medical University of South Carolina, Charleston, SC, USA.
- Departments of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, USA.
- Departments of Psychiatry and Neuroscience, Medical University of South Carolina, Charleston, SC, USA.
- RHJ Veterans Administration Health Care System, Medical University of South Carolina, Charleston, SC, USA.
| | - Marcelo F Lopez
- Charleston Alcohol Research Center, Medical University of South Carolina, Charleston, SC, USA
- Departments of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, USA
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Sanz-Martos AB, Fuentes-Verdugo E, Merino B, Morales L, Pérez V, Capellán R, Pellón R, Miguéns M, Del Olmo N. Schedule-induced alcohol intake during adolescence sex dependently impairs hippocampal synaptic plasticity and spatial memory. Behav Brain Res 2023; 452:114576. [PMID: 37423317 DOI: 10.1016/j.bbr.2023.114576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 06/16/2023] [Accepted: 07/06/2023] [Indexed: 07/11/2023]
Abstract
In a previous study, we demonstrated that intermittent ethanol administration in male adolescent animals impaired hippocampus-dependent spatial memory, particularly under conditions of excessive ethanol administration. In this current study, we subjected adolescent male and female Wistar rats an alcohol schedule-induced drinking (SID) procedure to obtain an elevated rate of alcohol self-administration and assessed their hippocampus-dependent spatial memory. We also studied hippocampal synaptic transmission and plasticity, as well as the expression levels of several genes involved in these mechanisms. Both male and female rats exhibited similar drinking patterns throughout the sessions of the SID protocol reaching similar blood alcohol levels in all the groups. However, only male rats that consumed alcohol showed spatial memory deficits which correlated with inhibition of hippocampal synaptic plasticity as long-term potentiation. In contrast, alcohol did not modify hippocampal gene expression of AMPA and NMDA glutamate receptor subunits, although there are differences in the expression levels of several genes relevant to synaptic plasticity mechanisms underlying learning and memory processes, related to alcohol consumption as Ephb2, sex differences as Pi3k or the interaction of both factors such as Pten. In conclusion, elevated alcohol intake during adolescence seems to have a negative impact on spatial memory and hippocampal synaptic plasticity in a sex dependent manner, even both sexes exhibit similar blood alcohol concentrations and drinking patterns.
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Affiliation(s)
- Ana Belén Sanz-Martos
- Department of Psychobiology, School of Psychology, UNED, C/Juan del Rosal 10, 28040 Madrid, Spain
| | - Esmeralda Fuentes-Verdugo
- Department of Basic Psychology I, School of Psychology, UNED, C/Juan del Rosal 10, 28040 Madrid, Spain
| | - Beatriz Merino
- Department of Pharmaceutical and Nutritional Sciences, School of Pharmacy, San Pablo-CEU University, Urb. Montepríncipe, Boadilla del Monte, Madrid, Spain
| | - Lidia Morales
- Department of Pharmaceutical and Nutritional Sciences, School of Pharmacy, San Pablo-CEU University, Urb. Montepríncipe, Boadilla del Monte, Madrid, Spain
| | - Vicente Pérez
- Department of Basic Psychology I, School of Psychology, UNED, C/Juan del Rosal 10, 28040 Madrid, Spain
| | - Roberto Capellán
- Department of Psychobiology, School of Psychology, UNED, C/Juan del Rosal 10, 28040 Madrid, Spain
| | - Ricardo Pellón
- Department of Basic Psychology I, School of Psychology, UNED, C/Juan del Rosal 10, 28040 Madrid, Spain
| | - Miguel Miguéns
- Department of Basic Psychology I, School of Psychology, UNED, C/Juan del Rosal 10, 28040 Madrid, Spain
| | - Nuria Del Olmo
- Department of Psychobiology, School of Psychology, UNED, C/Juan del Rosal 10, 28040 Madrid, Spain.
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Martín-González E, Olmedo-Córdoba M, Flores P, Moreno-Montoya M. Differential Neurobiological Markers in Phenotype-stratified Rats Modeling High or Low Vulnerability to Compulsive Behavior: A Narrative Review. Curr Neuropharmacol 2023; 21:1924-1933. [PMID: 36411566 PMCID: PMC10514532 DOI: 10.2174/1570159x21666221121091454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 09/15/2022] [Accepted: 10/31/2022] [Indexed: 11/23/2022] Open
Abstract
Compulsivity is a key manifestation of inhibitory control deficit and a cardinal symptom in different neuropsychopathological disorders such as obsessive-compulsive disorder, schizophrenia, addiction, and attention-deficit hyperactivity disorder. Schedule-induced polydipsia (SIP), is an animal model to study compulsivity. In this procedure, rodents develop excessive and persistent drinking behavior under different food-reinforcement schedules, that are not related to homeostatic or regulatory requirements. However, there are important individual differences that support the role of high-drinker HD rats as a compulsive phenotype, characterized in different paradigms by inhibitory response deficit, cognitive inflexibility, and resistant to extinction behavior; with significant differences in response to pharmacological challenges, and relevant neurobiological alterations in comparison with the control group, the non-compulsive low drinker LD group on SIP. The purpose of this review is to collate and update the main findings on the neurobiological bases of compulsivity using the SIP model. Specifically, we reviewed preclinical studies on SIP, that have assessed the effects of serotonergic, dopaminergic, and glutamatergic drugs; leading to the description of the neurobiological markers, such as the key role of the serotonin 5-HT2A receptor and glutamatergic signaling in a phenotype vulnerable to compulsivity as high drinker HD rats selected by SIP. The review of the main findings of HD rats on SIP helps in the characterization of the preclinical compulsive phenotype, disentangles the underlying neurobiological, and points toward genetic hallmarks concerning the vulnerability to compulsivity.
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Affiliation(s)
- Elena Martín-González
- Department of Psychology and Health Research Center (CEINSA), University of Almería, Almeria, Spain
| | - Manuela Olmedo-Córdoba
- Department of Psychology and Health Research Center (CEINSA), University of Almería, Almeria, Spain
| | - Pilar Flores
- Department of Psychology and Health Research Center (CEINSA), University of Almería, Almeria, Spain
| | - Margarita Moreno-Montoya
- Department of Psychology and Health Research Center (CEINSA), University of Almería, Almeria, Spain
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Negative valence system as a relevant domain in compulsivity: review in a preclinical model of compulsivity. Emerg Top Life Sci 2022; 6:491-500. [PMID: 36377776 DOI: 10.1042/etls20220005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 09/01/2022] [Accepted: 10/12/2022] [Indexed: 11/16/2022]
Abstract
Compulsive behavior is observed in different neuropsychiatric disorders such as Obsessive-Compulsive Disorder (OCD), anxiety, phobia, schizophrenia and addiction. Compulsivity has been proposed as a transdiagnostic symptom, where the Research Domain Criteria (RDoC) strategy could help to understand its neuropsychological basis for a better understanding, and development of therapeutic and preventive strategies. However, research on compulsivity has been focused on the cognitive control domain, and the contribution of an altered negative valence system has been less considered. In this review, we collate the main findings in an animal model of compulsivity, the high drinker (HD) rats selected by Schedule-Induced Polydipsia (SIP) regarding these two research domains. This preclinical model of compulsivity has shown a phenotype characterized by a lack of behavioral inhibition, impulsive decision-making and cognitive inflexibility. Moreover, the results in compulsive HD rats, suggests that there is also a relevant alteration in the emotional dimension, linked to the negative valence system domain, as for example by: the increased perseverative responses in a withdrawal condition, associated with the behavioral construct of frustrative non-reward; and an inhibition or extinction deficit in memory retrieval associated with an alteration in the behavioral response to sustained threat. However, the precise nature of the link between these shared altered domains, cognitive control and negative valence system, remains unknown. These results point towards relevant behavioral aspects of the compulsive phenotype that should be taken into account when studying the vulnerability to compulsivity that could help in the development of a better transdiagnostic assessment, preventive and therapeutic strategies.
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Merchán A, Pérez-Fernández C, López MJ, Moreno J, Moreno M, Sánchez-Santed F, Flores P. Dietary tryptophan depletion alters the faecal bacterial community structure of compulsive drinker rats in schedule-induced polydipsia. Physiol Behav 2021; 233:113356. [PMID: 33577871 DOI: 10.1016/j.physbeh.2021.113356] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Revised: 01/29/2021] [Accepted: 02/09/2021] [Indexed: 12/19/2022]
Abstract
RATIONALE Compulsive behaviour, present in different psychiatric disorders such as obsessive-compulsive disorder, schizophrenia and drug abuse, is associated with altered levels of serotonin (5-hydroxytryptamine, 5-HT). The gut microbiota regulates tryptophan (TRP) metabolism and may affect global 5-H synthesis in the enteric and central nervous systems, suggesting a possible involvement of gut microbiota in compulsive spectrum disorders. OBJECTIVES The present study investigated whether chronic TRP depletion by diet alters the faecal bacterial community profiles of compulsive versus non-compulsive rats in schedule-induced polydipsia (SIP). Peripheral plasma 5-HT and brain-derived neurotrophic factor (BDNF) levels were evaluated. METHODS Wistar rats were selected as High Drinkers (HD) or Low Drinkers (LD) according to their SIP behaviour and were fed for 14 days with either a TRP-free diet (T-) or a TRP-supplemented diet (T+). The faecal bacterial community structure was investigated with 16S rRNA gene-targeted denaturing gradient gel electrophoresis (DGGE) fingerprinting analysis. RESULTS Compulsive HD rats showed a lower bacterial diversity than LD rats, irrespectively of the diet. The TRP-depleted HD rats, the only group increasing compulsive licking in SIP, showed a reduction of bacterial evenness and a highly functionally organized community compared with the other groups, indicating that this bacterial community is more fragile to external changes due to the dominance of a low number of species. The chronic TRP depletion by diet effectively reduced peripheral plasma 5-HT levels in both HD and LD rats, while plasma BDNF levels were not altered. CONCLUSIONS These results highlight the possible implication of reduced microbial diversity in compulsive behaviour and the involvement of the serotonergic system in modulating the gut brain-axis in compulsive spectrum disorders.
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Affiliation(s)
- A Merchán
- Department of Psychology and Health Research Center (CEINSA), University of Almería, Ctra. Sacramento s/n, 04120 Almería, Spain
| | - C Pérez-Fernández
- Department of Psychology and Health Research Center (CEINSA), University of Almería, Ctra. Sacramento s/n, 04120 Almería, Spain
| | - M J López
- Department of Biology and Geology and CIAMBITAL, University of Almería & CeiA3, Ctra. Sacramento s/n, 04120, Almería, Spain
| | - J Moreno
- Department of Biology and Geology and CIAMBITAL, University of Almería & CeiA3, Ctra. Sacramento s/n, 04120, Almería, Spain
| | - M Moreno
- Department of Psychology and Health Research Center (CEINSA), University of Almería, Ctra. Sacramento s/n, 04120 Almería, Spain
| | - F Sánchez-Santed
- Department of Psychology and Health Research Center (CEINSA), University of Almería, Ctra. Sacramento s/n, 04120 Almería, Spain
| | - P Flores
- Department of Psychology and Health Research Center (CEINSA), University of Almería, Ctra. Sacramento s/n, 04120 Almería, Spain.
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7
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Merchán A, Sánchez-Kuhn A, Prados-Pardo A, Gago B, Sánchez-Santed F, Moreno M, Flores P. Behavioral and biological markers for predicting compulsive-like drinking in schedule-induced polydipsia. Prog Neuropsychopharmacol Biol Psychiatry 2019; 93:149-160. [PMID: 30940483 DOI: 10.1016/j.pnpbp.2019.03.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 03/26/2019] [Accepted: 03/29/2019] [Indexed: 01/21/2023]
Abstract
Schedule-induced polydipsia (SIP), characterized by the development of persistent and excessive drinking under intermittent food-reinforcement schedules, is an animal model of compulsive behavior that can differentiate two populations: high drinkers (HD) and low drinkers (LD). The aim of the present study was to identify behavioral and biological markers to predict the vulnerability to developing compulsive-like drinking in SIP. Adult male Wistar rats were first trained in a spatial-discrimination serial reversal-learning task and in a reinforcer devaluation task to measure behavioral flexibility and habit formation, respectively. Subsequently, the rats were tested using the SIP protocol and identified as HD or LD based on their drinking rates. The performance of HD and LD rats in the two previous tasks was then analyzed. Before and after SIP exposure, blood glucose and plasma corticosterone (CORT) levels were measured. Additionally, serum electrolyte levels, including sodium, potassium, and chloride, were analyzed after SIP. HD rats showed higher behavioral inflexibility by exhibiting increased perseverative responses in the reversal-learning task and insensitivity to reinforcer devaluation during extinction under selective satiation. After SIP exposure, HD rats exhibited increased basal plasma CORT levels, indicating that this vulnerable group might have a dysregulation of the HPA axis. Although HD and LD rats had blood glucose levels within normal range, the HD group showed lower levels. The HD group did not exhibit hyponatremia (i.e., reduced serum sodium levels) when compared to LD rats after 20 daily SIP sessions. The results of the present study demonstrated that HD rats exhibit behavioral inflexibility and greater habitual-like behavior before SIP. Moreover, these results highlight the importance of measuring different behavioral and biological markers for predicting the vulnerability to developing compulsivity, and for enhancing the understanding of the pathophysiology of compulsive spectrum disorders.
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Affiliation(s)
- A Merchán
- Department of Psychology & Health Research Centre, University of Almería, Almería, Spain
| | - A Sánchez-Kuhn
- Department of Psychology & Health Research Centre, University of Almería, Almería, Spain
| | - A Prados-Pardo
- Department of Psychology & Health Research Centre, University of Almería, Almería, Spain
| | - B Gago
- Department of Cell Biology, School of Science, University of Málaga, Málaga, Spain
| | - F Sánchez-Santed
- Department of Psychology & Health Research Centre, University of Almería, Almería, Spain
| | - M Moreno
- Department of Psychology & Health Research Centre, University of Almería, Almería, Spain
| | - P Flores
- Department of Psychology & Health Research Centre, University of Almería, Almería, Spain.
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Merchán A, Mora S, Gago B, Rodriguez-Ortega E, Fernández-Teruel A, Puga JL, Sánchez-Santed F, Moreno M, Flores P. Excessive habit formation in schedule-induced polydipsia: Microstructural analysis of licking among rat strains and involvement of the orbitofrontal cortex. GENES BRAIN AND BEHAVIOR 2018; 18:e12489. [DOI: 10.1111/gbb.12489] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 06/04/2018] [Accepted: 06/04/2018] [Indexed: 11/29/2022]
Affiliation(s)
- A. Merchán
- Department of Psychology and CIAMBITAL; University of Almería & CeiA3; Almería Spain
| | - S. Mora
- Department of Psychology and CIAMBITAL; University of Almería & CeiA3; Almería Spain
| | - B. Gago
- Department of Cell Biology, School of Science; University of Málaga; Málaga Spain
| | - E. Rodriguez-Ortega
- Department of Psychology and CIAMBITAL; University of Almería & CeiA3; Almería Spain
| | - A. Fernández-Teruel
- Department of Psychiatry and Forensic Medicine; Institute of Neurosciences, School of Medicine, Universitat Autònoma de Barcelona; Barcelona Spain
| | - J. L. Puga
- UCAM Universidad Católica de Murcia; Murcia Spain
| | - F. Sánchez-Santed
- Department of Psychology and CIAMBITAL; University of Almería & CeiA3; Almería Spain
| | - M. Moreno
- Department of Psychology and CIAMBITAL; University of Almería & CeiA3; Almería Spain
| | - P. Flores
- Department of Psychology and CIAMBITAL; University of Almería & CeiA3; Almería Spain
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Navarro SV, Alvarez R, Colomina MT, Sanchez-Santed F, Flores P, Moreno M. Behavioral Biomarkers of Schizophrenia in High Drinker Rats: A Potential Endophenotype of Compulsive Neuropsychiatric Disorders. Schizophr Bull 2017; 43:778-787. [PMID: 27872269 PMCID: PMC5472118 DOI: 10.1093/schbul/sbw141] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Psychogenic polydipsia, which is compulsive, non-regulatory fluid consumption, is present in 6%-20% of chronic psychiatric patients and frequently associated with the schizophrenia diagnosis. In the present study, we investigated the relation between schizophrenia-like symptoms and biomarkers with a compulsive drinking behavior phenotype in rats. Rats that were selected for low drinking vs high drinking behavior following schedule-induced polydipsia (SIP) were assessed in a latent inhibition (LI) paradigm using tone and electrical foot shock and in a spatial reversal learning task to evaluate behavioral inflexibility. We also analyzed the myelin basic protein in different brain areas of high drinker (HD) and low drinker (LD) rats. The HD rats, which were characterized by a compulsive drinking behavior on SIP, had a reduced level of LI effect and increased behavioral inflexibility in the spatial reversal learning task in comparison to the LD group. Moreover, HD rats showed less myelination in the center of the corpus callosum, striatum, and amygdala in comparison to LD rats. These findings strengthen the validity of HD rats that were selected by SIP as a possible phenotype of compulsive neuropsychiatric disorders, as evidenced by the existence of behaviors and biological markers that are related to schizophrenia and obsessive-compulsive disorder, including a reduced LI effect, behavioral inflexibility and reduced brain myelination. Future studies could contribute to the elucidation of the mechanisms underlying the compulsive phenotype of HD rats and its relation to vulnerability to schizophrenia.
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Affiliation(s)
- Silvia V. Navarro
- Department of Psychology, University of Almería, Campus de Excelencia Internacional Agroalimentario (CEIA3), Almería, Spain
| | - Roberto Alvarez
- Department of Psychology, University of Almería, Campus de Excelencia Internacional Agroalimentario (CEIA3), Almería, Spain
| | - M. Teresa Colomina
- Department of Psychology and Research Center for Behavior Assessment (CRAMC), Universitat Rovira i Virgili, Tarragona, Spain;,Research in Neurobehavior and Health (NEUROLAB), Universitat Rovira i Virgili, Tarragona, Spain
| | - Fernando Sanchez-Santed
- Department of Psychology, University of Almería, Campus de Excelencia Internacional Agroalimentario (CEIA3), Almería, Spain
| | - Pilar Flores
- Department of Psychology, University of Almería, Campus de Excelencia Internacional Agroalimentario (CEIA3), Almería, Spain
| | - Margarita Moreno
- Department of Psychology, University of Almería, Campus de Excelencia Internacional Agroalimentario (CEIA3), Almería, Spain
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Tryptophan depletion affects compulsive behaviour in rats: strain dependent effects and associated neuromechanisms. Psychopharmacology (Berl) 2017; 234:1223-1236. [PMID: 28280881 PMCID: PMC5362668 DOI: 10.1007/s00213-017-4561-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Accepted: 02/02/2017] [Indexed: 02/02/2023]
Abstract
RATIONALE Compulsive behaviour, present in different psychiatric disorders, such as obsessive-compulsive disorder, schizophrenia and drug abuse, is associated with altered levels of monoamines, particularly serotonin (5-hydroxytryptamine) and its receptor system. OBJECTIVES The present study investigated whether 5-HT manipulation, through a tryptophan (TRP) depletion by diet in Wistar and Lister Hooded rats, modulates compulsive drinking in schedule-induced polydipsia (SIP) and locomotor activity in the open-field test. The levels of dopamine, noradrenaline, serotonin and its metabolite were evaluated, as well as the 5-HT2A and 5-HT1A receptor binding, in different brain regions. METHODS Wistar rats were selected as high (HD) or low (LD) drinkers according to their SIP behaviour, while Lister hooded rats did not show SIP acquisition. Both strains were fed for 14 days with either a TRP-free diet (T-) or a TRP-supplemented diet (T+) RESULTS: The TRP depletion diet effectively reduced 5-HT levels in the frontal cortex, amygdala and hippocampus in both strains of rats. The TRP-depleted HD Wistar rats were more sensitive to 5-HT manipulation, exhibiting more licks on SIP than did the non-depleted HD Wistar rats, while the LD Wistar and the Lister Hooded rats did not exhibit differences in SIP. In contrast, the TRP-depleted Lister Hooded rats increased locomotor activity compared to the non-depleted rats, while no differences were found in the Wistar rats. Serotonin 2A receptor binding in the striatum was significantly reduced in the TRP-depleted HD Wistar rats. CONCLUSIONS These results suggest that alterations of the serotonergic system could be involved in compulsive behaviour in vulnerable populations.
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Íbias J, Miguéns M, Pellón R. Effects of dopamine agents on a schedule-induced polydipsia procedure in the spontaneously hypertensive rat and in Wistar control rats. J Psychopharmacol 2016; 30:856-66. [PMID: 27296274 DOI: 10.1177/0269881116652598] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The spontaneously hypertensive rat (SHR) has been proposed as an animal model for attention deficit hyperactivity disorder (ADHD), and typically develops excessive patterns of response under most behavioural protocols. Schedule-induced polydipsia (SIP) is the excessive water consumption that occurs as a schedule effect when food is intermittently delivered and animals are partially food- but not water-deprived. SIP has been used as a model of excessive behaviour, and considerable evidence has involved the dopaminergic system in its development and maintenance. The aim of this study was to evaluate the effects of the most common psychostimulants used in ADHD treatment on SIP, comparing their effects in SHRs with rats from control populations. SHR, Wistar Kyoto (WKY) and Wistar rats were submitted to a multiple fixed time (FT) food schedule with two components: 30 s and 90 s. The acute effects of different dopaminergic compounds were evaluated after 40 sessions of SIP acquisition. All animals showed higher adjunctive drinking under FT 30 s than FT 90 s, and SHRs displayed higher asymptotic SIP levels in FT 90 s compared to WKY and Wistar rats. SHRs were less sensitive to dopaminergic agents than control rats in terms of affecting rates of adjunctive drinking. These differences point to an altered dopaminergic system in the SHR and provide new insights into the neurobiological basis of ADHD pharmacological treatments.
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Affiliation(s)
- Javier Íbias
- Animal Behaviour Laboratories, Departamento de Psicología Básica I, Facultad de Psicología, Universidad Nacional de Educación a Distancia (UNED), Madrid, Spain
| | - Miguel Miguéns
- Animal Behaviour Laboratories, Departamento de Psicología Básica I, Facultad de Psicología, Universidad Nacional de Educación a Distancia (UNED), Madrid, Spain
| | - Ricardo Pellón
- Animal Behaviour Laboratories, Departamento de Psicología Básica I, Facultad de Psicología, Universidad Nacional de Educación a Distancia (UNED), Madrid, Spain
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12
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Navarro SV, Gutiérrez-Ferre V, Flores P, Moreno M. Activation of serotonin 5-HT2A receptors inhibits high compulsive drinking on schedule-induced polydipsia. Psychopharmacology (Berl) 2015; 232:683-97. [PMID: 25155310 DOI: 10.1007/s00213-014-3699-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 07/28/2014] [Indexed: 11/26/2022]
Abstract
RATIONALE Schedule-induced polydipsia (SIP) is an established model for studying compulsive behaviour in rats. Serotoninergic drugs effectively reduce compulsive drinking on SIP, and high compulsive drinker rats selected by SIP have shown differences in serotoninergic brain activity. However, the specific serotoninergic receptors that modulate compulsive SIP remain unclear. OBJECTIVE We investigated the functional role of serotonin 5-hydroxytryptamine 2A or C (5-HT2A/C) receptors in compulsive SIP behaviour. METHODS Rats were selected for low (LD) versus high drinking (HD) behaviour on SIP. The effects of the systemic administration of the selective serotonin reuptake inhibitor citalopram, selective norepinephrine reuptake inhibitor atomoxetine, serotonin 5-HT2A/C receptor agonist DOI hydrochloride ((±)-2,5-dimethoxy-4-iodoamphetamine), serotonin 5-HT2C receptor antagonist SB242084, serotonin 5-HT2A receptor antagonist ketanserin and M100907 were assessed on SIP. Subsequently, the effects of DOI were tested after the pre-administration of SB242084, ketanserin and M100907 on SIP. RESULTS Citalopram and DOI reduced compulsive drinking in HD compared with LD rats on SIP. In contrast, SB242084 increased compulsive drinking in HD compared with LD rats on SIP. Atomoxetine, ketanserin and M100907 had no effect on SIP. The reduction in water intake produced by DOI was blocked by ketanserin and M100907, but not by SB242084 administration, in HD rats. CONCLUSIONS These findings highlight the contribution of serotoninergic 5-HT2A/C receptors compared with noradrenergic mechanisms on SIP and reveal the "therapeutic" activation of serotonin 5-HT2A in the inhibition of the compulsive drinking behaviour in HD rats. Thus, it may represent a potentially new marker of vulnerability and provides additional insight for potential treatments on compulsive behaviours in neuropsychiatric populations.
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Affiliation(s)
- Silvia Victoria Navarro
- Department of Psychology, University of Almería, Campus de Excelencia Internacional Agroalimentario CeiA3, Carretera de Sacramento s/n, 04120, Almería, Spain
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A microstructural analysis of schedule-induced polydipsia reveals incentive-induced hyperactivity in an animal model of ADHD. Behav Brain Res 2014; 278:417-23. [PMID: 25447297 DOI: 10.1016/j.bbr.2014.10.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 10/13/2014] [Accepted: 10/17/2014] [Indexed: 11/23/2022]
Abstract
Recent research has suggested that frequent short bursts of activity characterize hyperactivity associated with attention deficit hyperactivity disorder (ADHD). This study determined whether such pattern is also visible in schedule-induced polydipsia (SIP) in the spontaneously hypertensive rat (SHR), an animal model of ADHD. Male SHR, Wistar Kyoto (WKY) and Wistar rats were exposed to 40 sessions of SIP using a multiple fixed-time (FT) schedule of food delivery with FT 30-s and FT 90-s components. Stable performance was analyzed to determine the extent to which SIP-associated drinking is organized in bouts. The Bi-Exponential Refractory Model (BERM) of free-operant performance was applied to schedule-induced licks. A model comparison analysis supported BERM as a description of SIP episodes: licks were not produced at a constant rate but organized into bouts within drinking episodes. FT 30-s induced similar overall licking rates, latencies to first licks and episode durations across strains; FT 90-s induced longer episode durations in SHRs and reduced licking rate in WKY and Wistar rats to nearly baseline levels. Across schedules, SHRs made more and shorter bouts when compared to the other strains. These results suggest an incentive-induced hyperactivity in SHR that has been observed in operant behaviour and in children with ADHD.
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Effects of histone deacetylase inhibitors on amygdaloid histone acetylation and neuropeptide Y expression: a role in anxiety-like and alcohol-drinking behaviours. Int J Neuropsychopharmacol 2014; 17:1207-20. [PMID: 24528596 PMCID: PMC4140694 DOI: 10.1017/s1461145714000054] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Recent studies have demonstrated the involvement of epigenetic mechanisms in psychiatric disorders, including alcoholism. Here, we investigated the effects of histone deacetylase (HDAC) inhibitor, trichostatin A (TSA) on amygdaloid HDAC-induced histone deacetylation and neuropeptide Y (NPY) expression and on anxiety-like and alcohol-drinking behaviours in alcohol-preferring (P) and -non-preferring (NP) rats. It was found that P rats displayed higher anxiety-like and alcohol-drinking behaviours, higher amygdaloid nuclear, but not cytosolic, HDAC activity, which was associated with increased HDAC2 protein levels and deficits in histone acetylation and NPY expression in the central (CeA) and medial nucleus of amygdala (MeA), as compared to NP rats. TSA treatment attenuated the anxiety-like and alcohol-drinking behaviours, with concomitant reductions in amygdaloid nuclear, but not cytosolic HDAC activity, and HDAC2, but not HDAC4, protein levels in the CeA and MeA of P rats, without effect in NP rats. TSA treatment also increased global histone acetylation (H3-K9 and H4-K8) and NPY expression in the CeA and MeA of P, but not in NP rats. Histone H3 acetylation within the NPY promoter was also innately lower in the amygdala of P rats compared with NP rats; which was normalized by TSA treatment. Voluntary ethanol intake in P, but not NP rats, produced anxiolytic effects and decreased the HDAC2 levels and increased histone acetylation in the CeA and MeA. These results suggest that higher HDAC2 expression-related deficits in histone acetylation may be involved in lower NPY expression in the amygdala of P rats, and operative in controlling anxiety-like and alcohol-drinking behaviours.
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Becker HC, Ron D. Animal models of excessive alcohol consumption: recent advances and future challenges. Alcohol 2014; 48:205-8. [PMID: 24811154 PMCID: PMC5081257 DOI: 10.1016/j.alcohol.2014.04.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 04/02/2014] [Indexed: 12/12/2022]
Affiliation(s)
- Howard C Becker
- Charleston Alcohol Research Center, Department of Psychiatry and Neurosciences, Medical University of South Carolina, Charleston, SC 29425, USA; RHJ Department of Veterans Affairs Medical Center, Charleston, SC 29425, USA.
| | - Dorit Ron
- Gallo Research Center, Department of Neurology, University of California San Francisco, San Francisco, CA 94143, USA
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Ford MM. Applications of schedule-induced polydipsia in rodents for the study of an excessive ethanol intake phenotype. Alcohol 2014; 48:265-76. [PMID: 24680665 DOI: 10.1016/j.alcohol.2014.01.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Revised: 11/27/2013] [Accepted: 01/23/2014] [Indexed: 01/12/2023]
Abstract
Schedule-induced polydipsia (SIP) is generated by subjecting a highly motivated animal to a sub-optimal rate of food reinforcement while also providing access to a fluid. SIP is one of several adjunctive (or displacement) behaviors that are expressed in an exaggerated form that is deemed 'excessive.' This feature makes SIP an attractive model for studying an excessive ethanol drinking phenotype in rodents. Multiple experimental variables are crucial for the full manifestation of adjunctive drinking, including the degree of food deprivation, the inter-pellet interval selected, and the size of the food reward offered. Although these variables were extensively studied and optimized for water polydipsia in rats, a similarly customized approach to ethanol SIP and application of the procedure in mice have largely been curtailed in favor of the default variable values historically used for water SIP in rats. Further, ethanol SIP also requires careful consideration of variables such as taste and ethanol concentration. Investigation of the stress axis and neurochemical systems such as dopamine and serotonin in mediating adjunctive drinking stemmed from two leading hypotheses regarding the underlying mechanisms of SIP generation: 1) SIP as a coping strategy to mitigate stress associated with the aversive environmental condition, and 2) SIP as a displacement of reward in a highly motivated animal. Ethanol SIP is a powerful model of excessive intake because it can generate an ethanol-dependent state and sustain frequent and intoxicating levels of blood ethanol with voluntary oral consumption. The required food deprivation and the loss of the excessive drinking phenotype following removal of the generator schedule are the two main limitations of the model. Future utility of ethanol SIP will be enhanced by more fully dissecting the underlying hormonal and neurochemical mechanisms and optimizing experimental variables for ethanol SIP on a per species and strain basis.
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Flores P, Sánchez-Kuhn A, Merchán A, Vilches O, García-Martín S, Moreno M. Schedule-Induced Polydipsia: Searching for the Endophenotype of Compulsive Behavior. ACTA ACUST UNITED AC 2014. [DOI: 10.4236/wjns.2014.43029] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Ford MM, Steele AM, McCracken AD, Finn DA, Grant KA. The relationship between adjunctive drinking, blood ethanol concentration and plasma corticosterone across fixed-time intervals of food delivery in two inbred mouse strains. Psychoneuroendocrinology 2013; 38:2598-610. [PMID: 23827168 PMCID: PMC3812349 DOI: 10.1016/j.psyneuen.2013.06.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 05/21/2013] [Accepted: 06/07/2013] [Indexed: 11/26/2022]
Abstract
Schedules of intermittent food delivery induce excessive fluid intake, termed schedule-induced polydipsia (SIP), and hypothalamic-pituitary-adrenal (HPA) axis activation is important for the expression and maintenance of this adjunctive behavior. Previous work has focused on examining the relationship between water intake and plasma corticosterone (CORT) in rats at a single or a limited range of fixed time (FT) intervals. However, little remains known regarding SIP and the corresponding stress response (1) across the bitonic function that epitomizes adjunctive behavior, (2) when ethanol is the available fluid, and (3) when a species other than rat or multiple strains are studied. Here we report the findings from ethanol-preferring C57BL/6J (B6) and non-preferring DBA/2J (D2) mice serially exposed to progressively larger FT intervals (0 → 60 min) and given access to either water or a 5% (v/v) ethanol solution. Following 2 weeks of experience with each schedule, blood samples were collected at the conclusion of the last 60-min session to evaluate CORT and the blood ethanol concentration (BEC) achieved. While both strains exhibited a bitonic function of ethanol intake and BEC that peaked at or near a 5-min interval, only D2 mice showed a similar response with water. In contrast, CORT levels rose monotonically with incremental increases in the FT interval regardless of the strain examined or fluid type offered, indicating that glucocorticoid release likely reflects the aversive aspects of increasing intervals between reinforcement rather than engagement in adjunctive behavior. These findings also caution against the use of a single intensity stressor to evaluate the relationship between stress and ethanol intake, as the magnitude of stress appears to affect ethanol consumption in a non-linear fashion.
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Affiliation(s)
- Matthew M. Ford
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon U.S.A,Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Science University, Portland, Oregon U.S.A,Corresponding Author: Matthew M. Ford, Ph.D., Division of Neuroscience, Oregon National Primate Research Center (L-584), Oregon Health & Science University, 505 NW 185th Avenue, Beaverton, OR 97006; Phone: 503-614-3716; Fax: 503-690-5384;
| | - Andrea M. Steele
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon U.S.A
| | - Aubrey D. McCracken
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon U.S.A
| | - Deborah A. Finn
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon U.S.A,Department of Research, Veterans Affairs Medical Center, Portland, Oregon U.S.A
| | - Kathleen A. Grant
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon U.S.A,Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Science University, Portland, Oregon U.S.A
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Schedule-induced polydipsia as a model of compulsive behavior: neuropharmacological and neuroendocrine bases. Psychopharmacology (Berl) 2012; 219:647-59. [PMID: 22113447 DOI: 10.1007/s00213-011-2570-3] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Accepted: 11/01/2011] [Indexed: 12/24/2022]
Abstract
BACKGROUND Schedule-induced polydipsia (SIP), characterized by the development of excessive drinking under intermittent food-reinforcement schedules, has been proposed as a successful model for obsessive-compulsive disorder (OCD), schizophrenia, and alcohol abuse. OBJECTIVES The purpose of this study was to review the main findings and current thinking regarding the use of SIP for compulsivity assessment and evaluate its contribution to improving our knowledge of the neurobehavioral mechanisms underlying the excessive behavior manifested in SIP relevant to compulsive behavior disorders. METHODS The literature reviews SIP procedure and surveys main findings about its neurobehavioral basis and pharmacology relevant to its possible status as a model for compulsive disorders. Specifically, we reviewed effects of antipsychotics and serotoninergic drugs used in the treatment of OCD and schizophrenia. We also considered individual differences in SIP and its relevance as a possible compulsivity endophenotype. CONCLUSIONS SIP represents an animal model of non-regulatory and excessive drinking that may be valid for studying the psychopharmacology of the compulsive phenotype and modeling different psychopathologies from compulsivity spectrum disorders.
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Poor inhibitory control and neurochemical differences in high compulsive drinker rats selected by schedule-induced polydipsia. Psychopharmacology (Berl) 2012; 219:661-72. [PMID: 22113449 DOI: 10.1007/s00213-011-2575-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Accepted: 11/04/2011] [Indexed: 12/26/2022]
Abstract
RATIONALE Schedule-induced polydipsia (SIP), characterized by the development of excessive drinking under intermittent food reinforcement schedules, has been proposed as a model for obsessive-compulsive disorder, schizophrenia and drug abuse. OBJECTIVES The purpose of this study is to investigate if individual differences in SIP reflect psychopathological behavioural traits related to lack of inhibitory control and reactivity to novelty, and if these differences have neurochemical correlates. METHODS Outbred Wistar rats were selected for being either high (HD) or low (LD) drinkers according to their SIP behaviour. We tested locomotor reactivity to a novel environment and inhibitory control on the five-choice serial reaction time task (5-CSRTT), under baseline vs. extinction conditions and following challenge with D: -amphetamine (saline, 0.5 or 1 mg/kg). Post-mortem analyses of the monoaminergic levels in different brain regions were also analysed. RESULTS Compared to LD animals, HD rats exhibiting SIP acquisition showed no differences in spontaneous locomotor reactivity to novelty. On the 5-CSRTT, HD rats showed a greater increase in perseverative responses under extinction, a trend towards elevated premature responses on baseline, and a significantly greater elevation of premature responses to D: -amphetamine 0.5 mg/kg. The HD animals also exhibited increased serotonin activity in the amygdala, and correlational analyses between the rate of drinking on SIP and monoamine levels also revealed altered dopaminergic mesolimbic function. CONCLUSIONS These findings show that HD rats selected by SIP exhibit compulsive and impulsive behaviour based on measures of performance on the five-choice serial reaction time task and associated with changes in monoaminergic systems in limbic-striatal circuitry.
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Pellón R, Ruíz A, Moreno M, Claro F, Ambrosio E, Flores P. Individual differences in schedule-induced polydipsia: Neuroanatomical dopamine divergences. Behav Brain Res 2011; 217:195-201. [DOI: 10.1016/j.bbr.2010.10.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2009] [Revised: 10/08/2010] [Accepted: 10/12/2010] [Indexed: 10/18/2022]
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Moreno M, Cardona D, Gómez MJ, Sánchez-Santed F, Tobeña A, Fernández-Teruel A, Campa L, Suñol C, Escarabajal MD, Torres C, Flores P. Impulsivity characterization in the Roman high- and low-avoidance rat strains: behavioral and neurochemical differences. Neuropsychopharmacology 2010; 35:1198-208. [PMID: 20090672 PMCID: PMC3055403 DOI: 10.1038/npp.2009.224] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2009] [Revised: 11/24/2009] [Accepted: 11/27/2009] [Indexed: 11/08/2022]
Abstract
The selective breeding of Roman high- (RHA) and low-avoidance (RLA) rats for rapid vs extremely poor acquisition of active avoidance behavior in a shuttle-box has generated two phenotypes with different emotional and motivational profiles. The phenotypic traits of the Roman rat lines/strains (outbred or inbred, respectively) include differences in sensation/novelty seeking, anxiety/fearfulness, stress responsivity, and susceptibility to addictive substances. We designed this study to characterize differences between the inbred RHA-I and RLA-I strains in the impulsivity trait by evaluating different aspects of the multifaceted nature of impulsive behaviors using two different models of impulsivity, the delay-discounting task and five-choice serial reaction time (5-CSRT) task. Previously, rats were evaluated on a schedule-induced polydipsia (SIP) task that has been suggested as a model of obsessive-compulsive disorder. RHA-I rats showed an increased acquisition of the SIP task, higher choice impulsivity in the delay-discounting task, and poor inhibitory control as shown by increased premature responses in the 5-CSRT task. Therefore, RHA-I rats manifested an increased impulsivity phenotype compared with RLA-I rats. Moreover, these differences in impulsivity were associated with basal neurochemical differences in striatum and nucleus accumbens monoamines found between the two strains. These findings characterize the Roman rat strains as a valid model for studying the different aspects of impulsive behavior and for analyzing the mechanisms involved in individual predisposition to impulsivity and its related psychopathologies.
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Affiliation(s)
- Margarita Moreno
- Departamento de Neurociencia y Ciencias de la Salud, Universidad de Almería, Almería, Spain
| | - Diana Cardona
- Departamento de Neurociencia y Ciencias de la Salud, Universidad de Almería, Almería, Spain
| | | | | | - Adolf Tobeña
- Departamento de Psiquiatria y Medicina Legal, Instituto de Neurociencias, Universidad Autónoma de Barcelona, Barcelona, Spain
| | - Alberto Fernández-Teruel
- Departamento de Psiquiatria y Medicina Legal, Instituto de Neurociencias, Universidad Autónoma de Barcelona, Barcelona, Spain
| | - Leticia Campa
- Instituto de Investigaciones Biomedicas de Barcelona, CSIC-IDIBAPS, CIBERESP (CS), CIBERSAM (LC), Barcelona, Spain
| | - Cristina Suñol
- Instituto de Investigaciones Biomedicas de Barcelona, CSIC-IDIBAPS, CIBERESP (CS), CIBERSAM (LC), Barcelona, Spain
| | | | - Carmen Torres
- Departamento de Psicología, Universidad de Jaén, Jaén, Spain
| | - Pilar Flores
- Departamento de Neurociencia y Ciencias de la Salud, Universidad de Almería, Almería, Spain
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Cardona D, López-Crespo G, Sánchez-Amate MC, Flores P, Sánchez-Santed F. Impulsivity as long-term sequelae after chlorpyrifos intoxication: time course and individual differences. Neurotox Res 2010; 19:128-37. [PMID: 20087798 DOI: 10.1007/s12640-009-9149-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2009] [Revised: 12/26/2009] [Accepted: 12/30/2009] [Indexed: 12/12/2022]
Abstract
Chlorpyrifos (CPF) is a common organophosphate (OP) insecticide that has been widely used in agriculture as a pesticide. The primary mechanism of acute toxic action of OPs is initiated by acetylcholinesterase (AChE) inhibition. However, non-AChE targets have also been proposed as alternative that contributes to the acute lethal action and side effects of short or long-term exposure. Recently, we have found that a single dose of 250 mg/kg CPF produces acceleration in acquisition on schedule-induced polydipsia (SIP) procedure 6 months after its administration. Moreover, CPF animals show a higher level of impulsivity in a delay-discounting task 1 year after acute administration, and these effects are potentiated when animals are divided into high (HD) and low (LD) drinkers in SIP. In the present study, rats were injected with a subcutaneous (sc) dose of 250 mg/kg of CPF, and 10 weeks later its effect on delay-discounting task was evaluated. Consequently, these animals were evaluated based on SIP, and divided into two populations (HD and LD) according to their rates of drinking in this task. One year after OP administration, these animals were re-evaluated in a delay-discounting task. Results revealed that the CPF-administered rats prefer immediate reward and show a more impulsive choice, 10 weeks after CPF administration. Furthermore, 1 year after it administration, only animals treated with CPF that are high drinkers on SIP are more impulsive than the rest of the groups Therefore, these data suggest that some individuals are more sensitive to OP intoxication than the others, at least in terms of durability of sequelae.
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Affiliation(s)
- D Cardona
- Departamento de Neurociencia y Ciencias de la Salud, Universidad de Almería, 04120, La Cañada, Almería, Spain.
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