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Sethi P, Mehan S, Khan Z, Chhabra S. Acetyl-11-keto-beta boswellic acid(AKBA) modulates CSTC-pathway by activating SIRT-1/Nrf2-HO-1 signalling in experimental rat model of obsessive-compulsive disorder: Evidenced by CSF, blood plasma and histopathological alterations. Neurotoxicology 2023; 98:61-85. [PMID: 37549874 DOI: 10.1016/j.neuro.2023.08.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 07/23/2023] [Accepted: 08/03/2023] [Indexed: 08/09/2023]
Abstract
Obsessive-Compulsive disorder (OCD) is a long-term and persistent mental illness characterised by obsessive thoughts and compulsive behaviours. Numerous factors can contribute to the development or progression of OCD. These factors may result from the dysregulation of multiple intrinsic cellular pathways, including SIRT-1, Nrf2, and HO-1. Inhibitors of selective serotonin reuptake (SSRIs) are effective first-line treatments for OCD. In our ongoing research, we have investigated the role of SIRT-1, Nrf2, and HO-1, as well as the neuroprotective potential of Acetyl-11-keto-beta boswellic acid (AKBA) against behavioural and neurochemical changes in rodents treated with 8-OH-DPAT. In addition, the effects of AKBA were compared to those of fluvoxamine (FLX), a standard OCD medication. Injections of 8-OH-DPAT into the intra-dorso raphe nuclei (IDRN) of rats for seven days induced repetitive and compulsive behaviour accompanied by elevated oxidative stress, inflammatory processes, apoptosis, and neurotransmitter imbalances in CSF, blood plasma, and brain samples. Chronic administration of AKBA at 50 mg/kg and 100 mg/kg p.o. restored histopathological alterations in the cortico-striatal-thalamo-cortical (CSTC) pathway, including the cerebral cortex, striatum, and hippocampal regions. Our investigation revealed that when AKBA and fluvoxamine were administered together, the alterations were restored to a greater degree than when administered separately. These findings demonstrate that the neuroprotective effect of AKBA can serve as an effective basis for developing a novel OCD treatment.
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Affiliation(s)
- Pranshul Sethi
- Division of Neuroscience, Division, Department of Pharmacology, ISF College of Pharmacy, Moga, Punjab, India
| | - Sidharth Mehan
- Division of Neuroscience, Division, Department of Pharmacology, ISF College of Pharmacy, Moga, Punjab, India.
| | - Zuber Khan
- Division of Neuroscience, Division, Department of Pharmacology, ISF College of Pharmacy, Moga, Punjab, India
| | - Swesha Chhabra
- Division of Neuroscience, Division, Department of Pharmacology, ISF College of Pharmacy, Moga, Punjab, India
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Meta-Chlorophenylpiperazine-Induced Behavioral Changes in Obsessive-Compulsive Disorder Research: A Systematic Review of Rodent Studies. Neuroscience 2022; 507:125-138. [PMID: 36332691 DOI: 10.1016/j.neuroscience.2022.10.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 10/20/2022] [Accepted: 10/26/2022] [Indexed: 11/09/2022]
Abstract
Meta-chlorophenylpiperazine (mCPP) was one of the first compounds used in clinical and preclinical studies that demonstrated the role of serotonin in Obsessive-Compulsive Disorder (OCD). This systematic review aimed to (a) identify publications that report in rodents the effects of mCPP relevant to OCD, (b) explore the methodological characteristics of these studies, and (c) summarize the profile of mCPP effects. A comprehensive literature search was performed using PubMed, Scopus, and Web of Science. Search terms were a combination of obsessive-compulsive disorder or OCD and meta-chlorophenylpiperazine or mCPP. Twenty-nine articles were included in the review. The years of publication ranged from 1993 to 2021. Most studies used adult male Wistar or Sprague-Dawley rats. The most frequent dose of mCPP was 1.0 mg/kg administered acutely, intraperitoneally. In general, available preclinical evidence suggests increased defensive and compulsive behaviors associated with a decreased locomotor activity. But other results besides these and the absence of significant mCPP effects were also observed. Among the factors that may contribute to the variability of mCPP effects, differences in methods are highlighted, such as characteristics of the species/strains studied, mCPP doses and treatment regimens used. The heterogeneity of the OCD-like behaviors evaluated and the interaction of mCPP with different receptors may also be critical variables for discrepancies in the findings with mCPP. The information described in this review may contribute to a better understanding of how mCPP-induced behavioral changes in rodents have been used to study OCD, highlighting the main challenges for future investigations in this field.
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Szechtman H, Dvorkin-Gheva A, Gomez-Marin A. A virtual library for behavioral performance in standard conditions-rodent spontaneous activity in an open field during repeated testing and after treatment with drugs or brain lesions. Gigascience 2022; 11:giac092. [PMID: 36261217 PMCID: PMC9581716 DOI: 10.1093/gigascience/giac092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 07/31/2022] [Accepted: 09/06/2022] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND Beyond their specific experiment, video records of behavior have future value-for example, as inputs for new experiments or for yet unknown types of analysis of behavior-similar to tissue or blood sample banks in life sciences where clinically derived or otherwise well-described experimental samples are stored to be available for some unknown potential future purpose. FINDINGS Research using an animal model of obsessive-compulsive disorder employed a standardized paradigm where the behavior of rats in a large open field was video recorded for 55 minutes on each test. From 43 experiments, there are 19,976 such trials that amount to over 2 years of continuous recording. In addition to videos, there are 2 video-derived raw data objects: XY locomotion coordinates and plots of animal trajectory. To motivate future use, the 3 raw data objects are annotated with a general schema-one that abstracts the data records from their particular experiment while providing, at the same time, a detailed list of independent variables bearing on behavioral performance. The raw data objects are deposited as 43 datasets but constitute, functionally, a library containing 1 large dataset. CONCLUSIONS Size and annotation schema give the library high reuse potential: in applications using machine learning techniques, statistical evaluation of subtle factors, simulation of new experiments, or as educational resource. Ultimately, the library can serve both as the seed and as the test bed to create a machine-searchable virtual library of linked open datasets for behavioral performance in defined conditions.
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Affiliation(s)
- Henry Szechtman
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - Anna Dvorkin-Gheva
- Department of Pathology & Molecular Medicine, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - Alex Gomez-Marin
- Department of Systems Neurobiology, Instituto de Neurociencias (CSIC-UMH), 03550 Sant Joan d'Alacant, Alicante, Spain
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Straathof M, Blezer ELA, Smeele CE, van Heijningen C, van der Toorn A, Buitelaar JK, Glennon JC, Otte WM, Dijkhuizen RM. Memantine treatment does not affect compulsive behavior or frontostriatal connectivity in an adolescent rat model for quinpirole-induced compulsive checking behavior. Psychopharmacology (Berl) 2022; 239:2457-2470. [PMID: 35419637 PMCID: PMC9293859 DOI: 10.1007/s00213-022-06139-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 04/04/2022] [Indexed: 11/28/2022]
Abstract
RATIONALE Compulsivity often develops during childhood and is associated with elevated glutamate levels within the frontostriatal system. This suggests that anti-glutamatergic drugs, like memantine, may be an effective treatment. OBJECTIVE Our goal was to characterize the acute and chronic effect of memantine treatment on compulsive behavior and frontostriatal network structure and function in an adolescent rat model of compulsivity. METHODS Juvenile Sprague-Dawley rats received repeated quinpirole, resulting in compulsive checking behavior (n = 32; compulsive) or saline injections (n = 32; control). Eight compulsive and control rats received chronic memantine treatment, and eight compulsive and control rats received saline treatment for seven consecutive days between the 10th and 12th quinpirole/saline injection. Compulsive checking behavior was assessed, and structural and functional brain connectivity was measured with diffusion MRI and resting-state fMRI before and after treatment. The other rats received an acute single memantine (compulsive: n = 12; control: n = 12) or saline injection (compulsive: n = 4; control: n = 4) during pharmacological MRI after the 12th quinpirole/saline injection. An additional group of rats received a single memantine injection after a single quinpirole injection (n = 8). RESULTS Memantine treatment did not affect compulsive checking nor frontostriatal structural and functional connectivity in the quinpirole-induced adolescent rat model. While memantine activated the frontal cortex in control rats, no significant activation responses were measured after single or repeated quinpirole injections. CONCLUSIONS The lack of a memantine treatment effect in quinpirole-induced compulsive adolescent rats may be partly explained by the interaction between glutamatergic and dopaminergic receptors in the brain, which can be evaluated with functional MRI.
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Affiliation(s)
- Milou Straathof
- Biomedical MR Imaging and Spectroscopy Group, Center for Image Sciences, University Medical Center Utrecht & Utrecht University, Heidelberglaan 100, 3584 CX, Utrecht, the Netherlands.
| | - Erwin L. A. Blezer
- Biomedical MR Imaging and Spectroscopy Group, Center for Image Sciences, University Medical Center Utrecht & Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, the Netherlands
| | - Christel E. Smeele
- Biomedical MR Imaging and Spectroscopy Group, Center for Image Sciences, University Medical Center Utrecht & Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, the Netherlands
| | - Caroline van Heijningen
- Biomedical MR Imaging and Spectroscopy Group, Center for Image Sciences, University Medical Center Utrecht & Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, the Netherlands
| | - Annette van der Toorn
- Biomedical MR Imaging and Spectroscopy Group, Center for Image Sciences, University Medical Center Utrecht & Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, the Netherlands
| | - Jan K. Buitelaar
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands ,Karakter Child and Adolescent Psychiatry University Center, Nijmegen, the Netherlands
| | - Jeffrey C. Glennon
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands ,Conway Institute of Biomolecular and Biomedical Research, School of Medicine, University College Dublin, Dublin 4, Ireland
| | - Willem M. Otte
- Biomedical MR Imaging and Spectroscopy Group, Center for Image Sciences, University Medical Center Utrecht & Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, the Netherlands ,Department of Pediatric Neurology, UMC Utrecht Brain Center, University Medical Center Utrecht and Utrecht University, Utrecht, the Netherlands
| | - Rick M. Dijkhuizen
- Biomedical MR Imaging and Spectroscopy Group, Center for Image Sciences, University Medical Center Utrecht & Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, the Netherlands
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Lagière M, Bosc M, Whitestone S, Benazzouz A, Chagraoui A, Millan MJ, De Deurwaerdère P. A Subset of Purposeless Oral Movements Triggered by Dopaminergic Agonists Is Modulated by 5-HT 2C Receptors in Rats: Implication of the Subthalamic Nucleus. Int J Mol Sci 2020; 21:ijms21228509. [PMID: 33198169 PMCID: PMC7698107 DOI: 10.3390/ijms21228509] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Revised: 11/04/2020] [Accepted: 11/05/2020] [Indexed: 02/06/2023] Open
Abstract
Dopaminergic medication for Parkinson’s disease is associated with troubling dystonia and dyskinesia and, in rodents, dopaminergic agonists likewise induce a variety of orofacial motor responses, certain of which are mimicked by serotonin2C (5-HT2C) receptor agonists. However, the neural substrates underlying these communalities and their interrelationship remain unclear. In Sprague-Dawley rats, the dopaminergic agonist, apomorphine (0.03–0.3 mg/kg) and the preferential D2/3 receptor agonist quinpirole (0.2–0.5 mg/kg), induced purposeless oral movements (chewing, jaw tremor, tongue darting). The 5-HT2C receptor antagonist 5-methyl-1-[[2-[(2-methyl-3-pyridyl)oxyl]-5-pyridyl]carbamoyl]-6-trifluoromethylindone (SB 243213) (1 mg/kg) reduced the oral responses elicited by specific doses of both agonists (0.1 mg/kg apomorphine; 0.5 mg/kg quinpirole). After having confirmed that the oral bouts induced by quinpirole 0.5 mg/kg were blocked by another 5-HT2C antagonist (6-chloro-5-methyl-1-[6-(2-methylpiridin-3-yloxy)pyridine-3-yl carbamoyl] indoline (SB 242084), 1 mg/kg), we mapped the changes in neuronal activity in numerous sub-territories of the basal ganglia using c-Fos expression. We found a marked increase of c-Fos expression in the subthalamic nucleus (STN) in combining quinpirole (0.5 mg/kg) with either SB 243213 or SB 242084. In a parallel set of electrophysiological experiments, the same combination of SB 243213/quinpirole produced an irregular pattern of discharge and an increase in the firing rate of STN neurons. Finally, it was shown that upon the electrical stimulation of the anterior cingulate cortex, quinpirole (0.5 mg/kg) increased the response of substantia nigra pars reticulata neurons corresponding to activation of the “hyperdirect” (cortico-subthalamonigral) pathway. This effect of quinpirole was abolished by the two 5-HT2C antagonists. Collectively, these results suggest that induction of orofacial motor responses by D2/3 receptor stimulation involves 5-HT2C receptor-mediated activation of the STN by recruitment of the hyperdirect (cortico-subthalamonigral) pathway.
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Affiliation(s)
- Mélanie Lagière
- Centre National de la Recherche Scientifique (Unité Mixte de Recherche 5287), 146 Rue Léo Saignat, 33076 Bordeaux CEDEX, France; (M.L.); (M.B.); (S.W.)
- Centre National de la Recherche Scientifique (Unité Mixte de Recherche 5293), 33076 Bordeaux CEDEX, France;
| | - Marion Bosc
- Centre National de la Recherche Scientifique (Unité Mixte de Recherche 5287), 146 Rue Léo Saignat, 33076 Bordeaux CEDEX, France; (M.L.); (M.B.); (S.W.)
- Centre National de la Recherche Scientifique (Unité Mixte de Recherche 5293), 33076 Bordeaux CEDEX, France;
| | - Sara Whitestone
- Centre National de la Recherche Scientifique (Unité Mixte de Recherche 5287), 146 Rue Léo Saignat, 33076 Bordeaux CEDEX, France; (M.L.); (M.B.); (S.W.)
| | - Abdelhamid Benazzouz
- Centre National de la Recherche Scientifique (Unité Mixte de Recherche 5293), 33076 Bordeaux CEDEX, France;
| | - Abdeslam Chagraoui
- Neuronal and Neuroendocrine Differentiation and Communication Laboratory, Institute for Research and Innovation in Biomedicine of Normandy (IRIB), Normandie Univ, UNIROUEN, INSERM, U1239, CHU Rouen, 76000 Rouen, France;
- Department of Medical Biochemistry, Rouen University Hospital, 76000 Rouen, France
| | - Mark J. Millan
- Institut de Recherche Servier, Center for Therapeutic Innovation in Neuropsychiatry, Croissy/Seine, 78290 Paris, France;
| | - Philippe De Deurwaerdère
- Centre National de la Recherche Scientifique (Unité Mixte de Recherche 5287), 146 Rue Léo Saignat, 33076 Bordeaux CEDEX, France; (M.L.); (M.B.); (S.W.)
- Correspondence: ; Tel.: +33-(0)-557-57-12-90
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Szechtman H, Harvey BH, Woody EZ, Hoffman KL. The Psychopharmacology of Obsessive-Compulsive Disorder: A Preclinical Roadmap. Pharmacol Rev 2020; 72:80-151. [PMID: 31826934 DOI: 10.1124/pr.119.017772] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
This review evaluates current knowledge about obsessive-compulsive disorder (OCD), with the goal of providing a roadmap for future directions in research on the psychopharmacology of the disorder. It first addresses issues in the description and diagnosis of OCD, including the structure, measurement, and appropriate description of the disorder and issues of differential diagnosis. Current pharmacotherapies for OCD are then reviewed, including monotherapy with serotonin reuptake inhibitors and augmentation with antipsychotic medication and with psychologic treatment. Neuromodulatory therapies for OCD are also described, including psychosurgery, deep brain stimulation, and noninvasive brain stimulation. Psychotherapies for OCD are then reviewed, focusing on behavior therapy, including exposure and response prevention and cognitive therapy, and the efficacy of these interventions is discussed, touching on issues such as the timing of sessions, the adjunctive role of pharmacotherapy, and the underlying mechanisms. Next, current research on the neurobiology of OCD is examined, including work probing the role of various neurotransmitters and other endogenous processes and etiology as clues to the neurobiological fault that may underlie OCD. A new perspective on preclinical research is advanced, using the Research Domain Criteria to propose an adaptationist viewpoint that regards OCD as the dysfunction of a normal motivational system. A systems-design approach introduces the security motivation system (SMS) theory of OCD as a framework for research. Finally, a new perspective on psychopharmacological research for OCD is advanced, exploring three approaches: boosting infrastructure facilities of the brain, facilitating psychotherapeutic relearning, and targeting specific pathways of the SMS network to fix deficient SMS shut-down processes. SIGNIFICANCE STATEMENT: A significant proportion of patients with obsessive-compulsive disorder (OCD) do not achieve remission with current treatments, indicating the need for innovations in psychopharmacology for the disorder. OCD may be conceptualized as the dysfunction of a normal, special motivation system that evolved to manage the prospect of potential danger. This perspective, together with a wide-ranging review of the literature, suggests novel directions for psychopharmacological research, including boosting support systems of the brain, facilitating relearning that occurs in psychotherapy, and targeting specific pathways in the brain that provide deficient stopping processes in OCD.
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Affiliation(s)
- Henry Szechtman
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada (H.S.); SAMRC Unit on Risk Resilience in Mental Disorders, Department of Psychiatry, University of Cape Town, and Center of Excellence for Pharmaceutical Sciences, School of Pharmacy, North-West University (Potchefstroom Campus), Potchefstroom, South Africa (B.H.H.); Department of Psychology, University of Waterloo, Waterloo, Ontario, Canada (E.Z.W.); and Centro de Investigación en Reproducción Animal, CINVESTAV-Universidad Autónoma de Tlaxcala, Tlaxcala, Mexico (K.L.H.)
| | - Brian H Harvey
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada (H.S.); SAMRC Unit on Risk Resilience in Mental Disorders, Department of Psychiatry, University of Cape Town, and Center of Excellence for Pharmaceutical Sciences, School of Pharmacy, North-West University (Potchefstroom Campus), Potchefstroom, South Africa (B.H.H.); Department of Psychology, University of Waterloo, Waterloo, Ontario, Canada (E.Z.W.); and Centro de Investigación en Reproducción Animal, CINVESTAV-Universidad Autónoma de Tlaxcala, Tlaxcala, Mexico (K.L.H.)
| | - Erik Z Woody
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada (H.S.); SAMRC Unit on Risk Resilience in Mental Disorders, Department of Psychiatry, University of Cape Town, and Center of Excellence for Pharmaceutical Sciences, School of Pharmacy, North-West University (Potchefstroom Campus), Potchefstroom, South Africa (B.H.H.); Department of Psychology, University of Waterloo, Waterloo, Ontario, Canada (E.Z.W.); and Centro de Investigación en Reproducción Animal, CINVESTAV-Universidad Autónoma de Tlaxcala, Tlaxcala, Mexico (K.L.H.)
| | - Kurt Leroy Hoffman
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada (H.S.); SAMRC Unit on Risk Resilience in Mental Disorders, Department of Psychiatry, University of Cape Town, and Center of Excellence for Pharmaceutical Sciences, School of Pharmacy, North-West University (Potchefstroom Campus), Potchefstroom, South Africa (B.H.H.); Department of Psychology, University of Waterloo, Waterloo, Ontario, Canada (E.Z.W.); and Centro de Investigación en Reproducción Animal, CINVESTAV-Universidad Autónoma de Tlaxcala, Tlaxcala, Mexico (K.L.H.)
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Straathof M, Blezer ELA, van Heijningen C, Smeele CE, van der Toorn A, Buitelaar JK, Glennon JC, Otte WM, Dijkhuizen RM. Structural and functional MRI of altered brain development in a novel adolescent rat model of quinpirole-induced compulsive checking behavior. Eur Neuropsychopharmacol 2020; 33:58-70. [PMID: 32151497 DOI: 10.1016/j.euroneuro.2020.02.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 02/07/2020] [Accepted: 02/17/2020] [Indexed: 01/31/2023]
Abstract
Obsessive-compulsive disorder (OCD) is increasingly considered to be a neurodevelopmental disorder. However, despite insights in neural substrates of OCD in adults, less is known about mechanisms underlying compulsivity during brain development in children and adolescents. Therefore, we developed an adolescent rat model of compulsive checking behavior and investigated developmental changes in structural and functional measures in the frontostriatal circuitry. Five-weeks old Sprague Dawley rats were subcutaneously injected with quinpirole (n = 21) or saline (n = 20) twice a week for five weeks. Each injection was followed by placement in the middle of an open field table, and compulsive behavior was quantified as repeated checking behavior. Anatomical, resting-state functional and diffusion MRI at 4.7T were conducted before the first and after the last quinpirole/saline injection to measure regional volumes, functional connectivity and structural integrity in the brain, respectively. After consecutive quinpirole injections, adolescent rats demonstrated clear checking behavior and repeated travelling between two open-field zones. MRI measurements revealed an increase of regional volumes within the frontostriatal circuits and an increase in fractional anisotropy (FA) in white matter areas during maturation in both experimental groups. Quinpirole-injected rats showed a larger developmental increase in FA values in the internal capsule and forceps minor compared to control rats. Our study points toward a link between development of compulsive behavior and altered white matter maturation in quinpirole-injected adolescent rats, in line with observations in pediatric patients with compulsive phenotypes. This novel animal model provides opportunities to investigate novel treatments and underlying mechanisms for patients with early-onset OCD specifically.
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Affiliation(s)
- Milou Straathof
- Biomedical MR Imaging and Spectroscopy Group, Center for Image Sciences, University Medical Center Utrecht and Utrecht University, Utrecht, the Netherlands.
| | - Erwin L A Blezer
- Biomedical MR Imaging and Spectroscopy Group, Center for Image Sciences, University Medical Center Utrecht and Utrecht University, Utrecht, the Netherlands
| | - Caroline van Heijningen
- Biomedical MR Imaging and Spectroscopy Group, Center for Image Sciences, University Medical Center Utrecht and Utrecht University, Utrecht, the Netherlands
| | - Christel E Smeele
- Biomedical MR Imaging and Spectroscopy Group, Center for Image Sciences, University Medical Center Utrecht and Utrecht University, Utrecht, the Netherlands
| | - Annette van der Toorn
- Biomedical MR Imaging and Spectroscopy Group, Center for Image Sciences, University Medical Center Utrecht and Utrecht University, Utrecht, the Netherlands
| | - Jan K Buitelaar
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands; Karakter Child and Adolescent Psychiatry University Center, Nijmegen, the Netherlands
| | - Jeffrey C Glennon
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Willem M Otte
- Biomedical MR Imaging and Spectroscopy Group, Center for Image Sciences, University Medical Center Utrecht and Utrecht University, Utrecht, the Netherlands; Department of Pediatric Neurology, UMC Utrecht Brain Center, University Medical Center Utrecht and Utrecht University, Utrecht, the Netherlands
| | - Rick M Dijkhuizen
- Biomedical MR Imaging and Spectroscopy Group, Center for Image Sciences, University Medical Center Utrecht and Utrecht University, Utrecht, the Netherlands
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Eagle DM, Schepisi C, Chugh S, Desai S, Han SYS, Huang T, Lee JJ, Sobala C, Ye W, Milton AL, Robbins TW. Dissociable dopaminergic and pavlovian influences in goal-trackers and sign-trackers on a model of compulsive checking in OCD. Psychopharmacology (Berl) 2020; 237:3569-3581. [PMID: 32886158 PMCID: PMC7683452 DOI: 10.1007/s00213-020-05636-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 08/07/2020] [Indexed: 01/05/2023]
Abstract
RATIONALE Checking is a functional behaviour that provides information to guide behaviour. However, in obsessive-compulsive disorder (OCD), checking may escalate to dysfunctional levels. The processes underpinning the transition from functional to dysfunctional checking are unclear but may be associated with individual differences that support the development of maladaptive behaviour. We examined one such predisposition, sign-tracking to a pavlovian conditioned stimulus, which we previously found associated with dysfunctional checking. How sign-tracking interacts with another treatment with emerging translational validity for OCD-like checking, chronic administration of the dopamine D2 receptor agonist quinpirole, is unknown. OBJECTIVES We tested how functional and dysfunctional checking in the rat observing response task (ORT) was affected by chronic quinpirole administration in non-autoshaped controls and autoshaped animals classified as sign-trackers or goal-trackers. METHODS Sign-trackers or goal-trackers were trained on the ORT before the effects of chronic quinpirole administration on checking were assessed. Subsequently, the effects on checking of different behavioural challenges, including reward omission and the use of unpredictable reinforcement schedules, were tested. RESULTS Prior autoshaping increased checking. Sign-trackers and goal-trackers responded differently to quinpirole sensitization, reward omission and reinforcement uncertainty. Sign-trackers showed greater elevations in dysfunctional checking, particularly during uncertainty. By contrast, goal-trackers predominantly increased functional checking responses, possibly in response to reduced discrimination accuracy in the absence of cues signalling which lever was currently active. CONCLUSIONS The results are discussed in terms of how pavlovian associations influence behaviour that becomes compulsive in OCD and how this may be dependent on striatal dopamine D2 receptors.
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Affiliation(s)
- D. M. Eagle
- grid.5335.00000000121885934Department of Psychology, University of Cambridge, Downing Site, Cambridge, CB2 3EB UK
| | - C. Schepisi
- grid.5335.00000000121885934Department of Psychology, University of Cambridge, Downing Site, Cambridge, CB2 3EB UK ,grid.7841.aSapienza University of Rome, Rome, Italy
| | - S. Chugh
- grid.5335.00000000121885934Department of Psychology, University of Cambridge, Downing Site, Cambridge, CB2 3EB UK
| | - S. Desai
- grid.5335.00000000121885934Department of Psychology, University of Cambridge, Downing Site, Cambridge, CB2 3EB UK
| | - S. Y. S. Han
- grid.5335.00000000121885934Department of Psychology, University of Cambridge, Downing Site, Cambridge, CB2 3EB UK
| | - T. Huang
- grid.5335.00000000121885934Department of Psychology, University of Cambridge, Downing Site, Cambridge, CB2 3EB UK
| | - J. J. Lee
- grid.5335.00000000121885934Department of Psychology, University of Cambridge, Downing Site, Cambridge, CB2 3EB UK ,grid.5337.20000 0004 1936 7603University of Bristol, Bristol, UK ,grid.83440.3b0000000121901201University College London, London, UK
| | - C. Sobala
- grid.5335.00000000121885934Department of Psychology, University of Cambridge, Downing Site, Cambridge, CB2 3EB UK
| | - W. Ye
- grid.5335.00000000121885934Department of Psychology, University of Cambridge, Downing Site, Cambridge, CB2 3EB UK ,grid.4991.50000 0004 1936 8948Oxford University Clinical Academic Graduate School, University of Oxford, Oxford, UK
| | - A. L. Milton
- grid.5335.00000000121885934Department of Psychology, University of Cambridge, Downing Site, Cambridge, CB2 3EB UK
| | - T. W. Robbins
- grid.5335.00000000121885934Department of Psychology, University of Cambridge, Downing Site, Cambridge, CB2 3EB UK
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Woody EZ, Hoffman KL, Szechtman H. Obsessive compulsive disorder (OCD): Current treatments and a framework for neurotherapeutic research. ADVANCES IN PHARMACOLOGY 2019; 86:237-271. [PMID: 31378254 DOI: 10.1016/bs.apha.2019.04.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
We briefly review current approaches to the diagnosis and treatment of OCD, noting their lack of a strong theoretical foundation. In keeping with the Research Domain Criteria project (RDoC) calls for reconceptualizing psychopathology in ways that better link up with normal brain systems, we advance an adaptationist, brain-network perspective on OCD and propose that OCD represents a dysfunction in the stopping dynamics of a normal brain network that evolved to handle potential danger. We then illustrate how this theoretical perspective can be used to organize possibilities for research on neurotherapeutics for OCD and suggest novel directions for future work.
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Affiliation(s)
- Erik Z Woody
- Department of Psychology, University of Waterloo, Waterloo, ON, Canada
| | - Kurt Leroy Hoffman
- Centro de Investigación en Reproducción Animal (CIRA), Universidad Autónoma de Tlaxcala-CINVESTAV, Tlaxcala, Mexico
| | - Henry Szechtman
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON, Canada.
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Changes in gut microbiota during development of compulsive checking and locomotor sensitization induced by chronic treatment with the dopamine agonist quinpirole. Behav Pharmacol 2019; 29:211-224. [PMID: 29194070 DOI: 10.1097/fbp.0000000000000363] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Long-term treatment of rats with the D2/D3 dopamine agonist quinpirole induces compulsive checking (proposed as animal model of obsessive-compulsive disorder) and locomotor sensitization. The mechanisms by which long-term use of quinpirole produces those behavioral transformations are not known. Here we examined whether changes in gut microbiota play a role in these behavioral phenomena, by monitoring the development of compulsive checking and locomotor sensitization at the same time as measuring the response of gut microbiota to chronic quinpirole injections. Two groups of rats received nine injections of saline (n=16) or quinpirole (n=15; 0.25 mg/kg), at weekly intervals for the first 5 weeks and then two injections per week until the end of treatment. After each injection, rats were placed on a large open field for 55 min, and their behavior was video recorded for subsequent analysis. Fecal matter was collected after each trial and frozen for bacterial community profiling of the 16S rRNA gene, using paired-end reads of the V3 region. The results indicated that the induction of locomotor sensitization and compulsive checking was accompanied by changes in several communities of bacteria belonging to the order Clostridiales (class Clostridia, phylum Firmicutes), and predominantly in Lachnospiraceae and Ruminococcaceae families of bacteria. It is suggested that changes in these microbes may serve to support the energy use requirements of compulsive checking and obsessive-compulsive disorder.
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Dorfman A, Szechtman H, Eilam D. Social interaction modulates the intensity of compulsive checking in a rat model of obsessive-compulsive disorder (OCD). Behav Brain Res 2019; 359:156-164. [DOI: 10.1016/j.bbr.2018.10.038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 10/09/2018] [Accepted: 10/29/2018] [Indexed: 02/06/2023]
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Dardou D, Reyrolle L, Chassain C, Durif F. Chronic pramipexole treatment induces compulsive behavior in rats with 6-OHDA lesions of the substantia nigra and ventral tegmental area. Behav Brain Res 2017. [PMID: 28634107 DOI: 10.1016/j.bbr.2017.06.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Dopamine replacement therapy (DRT) reduces motor symptoms in Parkinson's disease (PD), but also induces impulsive-compulsive behavior (ICB) in up to 25% of PD patients. These non-motor side effects of DRT generally follow a gradual transition from impulsive to compulsive-like-i.e. repetitive, compelled, and non-pleasurable-behavior. Here, we investigated the effect of chronic pramipexole (PPX) treatment on the onset of compulsive-like behavior, measured via the post-training signal attenuation (PTSA) procedure, in rats with dopaminergic lesions. Accordingly, we aimed to mimic chronic DRT in a PD context, and obtain data on the brain regions that potentially sustain this type of compulsive behavior pattern in rats. We observed that the lesion or treatment alone did not induce compulsive lever pressing in rats. However, rats with lesions of the substantia nigra and ventral tegmental area as well as with chronic PPX treatment developed strong compulsive lever-pressing behavior, as measured via PTSA. Furthermore, when chronic PPX treatment was discontinued before the PTSA test, the lesioned rats showed the same level of compulsive behavior as sham-operated rats. In fact, lesioned, treated, and compulsive-like rats showed significantly higher Fos expression in the orbitofrontal cortex and dorsal striatum. Thus, chronic PPX treatment in PD rats induced a strong compulsive-like behavior. Furthermore, Fos expression mapping suggests that the behavior was sustained via the activation of the orbitofrontal cortex and dorsal striatum.
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Affiliation(s)
- D Dardou
- Biopathologie de la myéline, neuroprotection et stratégies thérapeutiques, INSERM U 1119, Université de Strasbourg, Faculté de Médecine, 4 Rue Kirschleger, 67000 Strasbourg, France.
| | - L Reyrolle
- Université Clermont Auvergne (UcA), EA7280 NPSY-Sydo, 28 Pl. H. Dunant, 63001 Clermont-Ferrand, France
| | - C Chassain
- Université Clermont Auvergne (UcA), EA7280 NPSY-Sydo, 28 Pl. H. Dunant, 63001 Clermont-Ferrand, France
| | - F Durif
- Université Clermont Auvergne (UcA), EA7280 NPSY-Sydo, 28 Pl. H. Dunant, 63001 Clermont-Ferrand, France; Service de Neurologie A, Hospital Gabriel Montpied, Clermont-Ferrand, France
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Eilam D. From an animal model to human patients: An example of a translational study on obsessive compulsive disorder (OCD). Neurosci Biobehav Rev 2017; 76:67-76. [DOI: 10.1016/j.neubiorev.2016.12.034] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 12/05/2016] [Accepted: 12/16/2016] [Indexed: 01/26/2023]
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Szechtman H, Ahmari SE, Beninger RJ, Eilam D, Harvey BH, Edemann-Callesen H, Winter C. Obsessive-compulsive disorder: Insights from animal models. Neurosci Biobehav Rev 2017; 76:254-279. [PMID: 27168347 PMCID: PMC5833926 DOI: 10.1016/j.neubiorev.2016.04.019] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 04/22/2016] [Accepted: 04/26/2016] [Indexed: 01/15/2023]
Abstract
Research with animal models of obsessive-compulsive disorder (OCD) shows the following: (1) Optogenetic studies in mice provide evidence for a plausible cause-effect relation between increased activity in cortico-basal ganglia-thalamo-cortical (CBGTC) circuits and OCD by demonstrating the induction of compulsive behavior with the experimental manipulation of the CBGTC circuit. (2) Parallel use of several animal models is a fruitful paradigm to examine the mechanisms of treatment effects of deep brain stimulation in distinct OCD endophenotypes. (3) Features of spontaneous behavior in deer mice constitute a rich platform to investigate the neurobiology of OCD, social ramifications of a compulsive phenotype, and test novel drugs. (4) Studies in animal models for psychiatric disorders comorbid with OCD suggest comorbidity may involve shared neural circuits controlling expression of compulsive behavior. (5) Analysis of compulsive behavior into its constitutive components provides evidence from an animal model for a motivational perspective on OCD. (6) Methods of behavioral analysis in an animal model translate to dissection of compulsive rituals in OCD patients, leading to diagnostic tests.
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Affiliation(s)
- Henry Szechtman
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON, Canada.
| | - Susanne E Ahmari
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA.
| | - Richard J Beninger
- Departments of Psychology and Psychiatry, Queen's University, Kingston, ON, Canada.
| | - David Eilam
- Department of Zoology, Tel-Aviv University, Ramat-Aviv 69978, Israel.
| | - Brian H Harvey
- MRC Unit on Anxiety and Stress Disorders, Center of Excellence for Pharmaceutical Sciences, School of Pharmacy, North-West University, Potchefstroom, South Africa.
| | - Henriette Edemann-Callesen
- Bereich Experimentelle Psychiatrie, Klinik und Poliklinik für Psychiatrie und Psychotherapie, Universitätsklinikum Carl Gustav Carus an der Technischen Universität Dresden, Dresden, Germany.
| | - Christine Winter
- Bereich Experimentelle Psychiatrie, Klinik und Poliklinik für Psychiatrie und Psychotherapie, Universitätsklinikum Carl Gustav Carus an der Technischen Universität Dresden, Dresden, Germany.
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Ballester González J, Dvorkin-Gheva A, Silva C, Foster JA, Szechtman H. Nucleus accumbens core and pathogenesis of compulsive checking. Behav Pharmacol 2015; 26:200-16. [PMID: 25426580 PMCID: PMC5398318 DOI: 10.1097/fbp.0000000000000112] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2014] [Accepted: 10/16/2014] [Indexed: 11/26/2022]
Abstract
To investigate the role of the nucleus accumbens core (NAc) in the development of quinpirole-induced compulsive checking, rats received an excitotoxic lesion of NAc or sham lesion and were injected with quinpirole (0.5 mg/kg) or saline; development of checking behavior was monitored for 10 biweekly tests. The results showed that even after the NAc lesion, quinpirole still induced compulsive checking, suggesting that the pathogenic effects produced by quinpirole lie outside the NAc. Although the NAc lesion did not prevent the induction of compulsive checking, it altered how quickly it develops, suggesting that the NAc normally contributes toward the induction of compulsive checking. Saline-treated rats with an NAc lesion were hyperactive, but did not develop compulsive checking, indicating that hyperactivity by itself is not sufficient for the pathogenesis of compulsive checking. It is proposed that compulsive checking is the exaggerated output of a security motivation system and that the NAc serves as a neural hub for coordinating the orderly activity of neural modules of this motivational system. Evidence is considered suggesting that the neurobiological condition for the pathogenesis of compulsive checking is two-fold: activation of dopamine D2/D3 receptors without concurrent stimulation of D1-like receptors and long-term plastic changes related to quinpirole-induced sensitization.
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Affiliation(s)
| | - Anna Dvorkin-Gheva
- Department of Psychiatry and Behavioral Neurosciences, McMaster University, Hamilton, Ontario, Canada
| | - Charmaine Silva
- Department of Psychiatry and Behavioral Neurosciences, McMaster University, Hamilton, Ontario, Canada
| | - Jane A. Foster
- Department of Psychiatry and Behavioral Neurosciences, McMaster University, Hamilton, Ontario, Canada
| | - Henry Szechtman
- Department of Psychiatry and Behavioral Neurosciences, McMaster University, Hamilton, Ontario, Canada
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Brown RW, Peterson DJ. Applications of the Neonatal Quinpirole Model to Psychosis and Convergence upon the Dopamine D 2 Receptor. Curr Top Behav Neurosci 2015; 29:387-402. [PMID: 26472551 DOI: 10.1007/7854_2015_394] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This mini review focuses on the importance of the dopamine D2-like receptor family and its importance in psychosis. Past findings from this laboratory along with collaborators have been that neonatal quinpirole (a dopamine D2-like receptor agonist) results in increases in dopamine D2 receptor sensitivity that persists throughout the animal's lifetime. Findings from this model have been shown to have particular application and validity to schizophrenia, but may have broader implications toward other psychoses, which is reviewed in the present manuscript. In the present review, we also highlight other models of psychoses that have been centered on the subchronic administration of quinpirole to rats in order to model certain psychoses, which has uncovered some interesting and valid behavioral findings. This review highlights the importance of the combination of behavioral findings and neurobiological mechanisms focusing on neural plasticity in discovering underlying pathologies in these disorders that may lead to treatment discoveries, as well as the value of animal models across all psychoses.
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Affiliation(s)
- Russell W Brown
- Department of Biomedical Science, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN, 37614-1702, USA.
| | - Daniel J Peterson
- Department of Psychology, East Tennessee State University, Johnson City, TN, 37614-1702, USA
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Tucci MC, Dvorkin-Gheva A, Johnson E, Wong M, Szechtman H. 5-HT2A/C receptors do not mediate the attenuation of compulsive checking by mCPP in the quinpirole sensitization rat model of obsessive-compulsive disorder (OCD). Behav Brain Res 2014; 279:211-7. [PMID: 25449840 DOI: 10.1016/j.bbr.2014.11.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Revised: 11/04/2014] [Accepted: 11/08/2014] [Indexed: 11/16/2022]
Abstract
There is emerging evidence for a dopamine (DA)-serotonin (5-HT) interaction underlying obsessive-compulsive disorder (OCD). In the quinpirole sensitization rat model of OCD, compulsive checking is induced by chronic treatment with the DA agonist quinpirole, and is attenuated by the 5-HT agonist drug mCPP. However, mCPP has affinity for a number of 5-HT receptor subtypes, and it is unknown by which receptors mCPP exerts its effects on quinpirole-treated animals. The present study tested in rats whether mCPP activity at 5-HT2A/C receptors mediates the attenuation of compulsive checking in quinpirole-treated animals. Rats were chronically treated with quinpirole on the open field for the induction of compulsive checking. Following the induction phase, animals were treated with mCPP (1.25 mg/kg) and the selective 5-HT2A/C receptor antagonist ritanserin (1 mg/kg or 5 mg/kg) to test whether blockade of 5-HT2A/C receptors inhibits attenuation of checking by mCPP. Results showed that as expected, quinpirole induced compulsive checking, and mCPP reduced its performance. However, 5-HT2A/C receptor blockade by ritanserin did not inhibit the attenuation of compulsive checking by mCPP. These results suggest that the reduction in compulsive checking by mCPP is not mediated by activity at 5-HT2A/C receptors, but by another receptor subtype.
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Affiliation(s)
- Mark C Tucci
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, HSC, 4N7, 1280 Main Street West, Hamilton, ON, Canada L8S4L8.
| | - Anna Dvorkin-Gheva
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, HSC, 4N7, 1280 Main Street West, Hamilton, ON, Canada L8S4L8
| | - Eric Johnson
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, HSC, 4N7, 1280 Main Street West, Hamilton, ON, Canada L8S4L8
| | - Michael Wong
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, HSC, 4N7, 1280 Main Street West, Hamilton, ON, Canada L8S4L8
| | - Henry Szechtman
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, HSC, 4N7, 1280 Main Street West, Hamilton, ON, Canada L8S4L8
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Tucci MC, Dvorkin-Gheva A, Johnson E, Cheon P, Taji L, Agarwal A, Foster J, Szechtman H. Performance of compulsive behavior in rats is not a unitary phenomenon - validation of separate functional components in compulsive checking behavior. Eur J Neurosci 2014; 40:2971-9. [PMID: 24935528 PMCID: PMC4215607 DOI: 10.1111/ejn.12652] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 05/06/2014] [Accepted: 05/08/2014] [Indexed: 11/29/2022]
Abstract
A previous analysis of the quinpirole sensitisation rat model of obsessive-compulsive disorder revealed that the behavioral phenotype of compulsive checking consists of three constitutive components – vigor of checking performance, focus on the task of checking, and satiety following a bout of checking. As confirmation of this analysis, the aim of the present study was to reconstitute, without quinpirole treatment, each of the putative components, with the expectation that these would self-assemble into compulsive checking. To reconstitute vigor and satiety, the employed treatment was a bilateral lesion of the nucleus accumbens core (NAc), as this treatment was shown previously to exaggerate these components. To reconstitute focus, the employed treatment was a low dose of the serotonin-1A receptor agonist 8-hydroxy-2-(di-n-propylamino) tetralin hydrochloride (DPAT) (0.0625 mg/kg), as high doses of this drug induce compulsive behavior and exacerbate focus. Results showed that injection of DPAT to NAc lesion rats did yield compulsive checking. Neither the drug alone nor the NAc lesion by itself produced compulsive checking. The demonstrated synthesis of compulsive checking by the combined treatment of low-dose DPAT and NAc lesion strengthened the previous fractionation of the model obsessive-compulsive disorder phenotype into three constitutive components, and suggested a role for serotonin-1A receptors outside the NAc in enhanced focus on the task of checking.
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Affiliation(s)
- Mark C Tucci
- Department of Psychiatry and Behavioural Neurosciences, Health Science Centre, McMaster University, Room 4N82, 1280 Main Street West, Hamilton, ON, Canada, L8S 4K1
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