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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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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; 11:6756450. [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] [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
- Correspondence address. Henry Szechtman, Department of Psychiatry and Behavioural Neurosciences, McMaster University, 1280 Main Street West, Health Science Centre, Room 4N82, Hamilton, Ontario, Canada L8S 4K1. E-mail:
| | - 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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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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Derksen M, Feenstra M, Willuhn I, Denys D. The serotonergic system in obsessive-compulsive disorder. HANDBOOK OF BEHAVIORAL NEUROSCIENCE 2020. [DOI: 10.1016/b978-0-444-64125-0.00044-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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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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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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A dose-response study of separate and combined effects of the serotonin agonist 8-OH-DPAT and the dopamine agonist quinpirole on locomotor sensitization, cross-sensitization, and conditioned activity. Behav Pharmacol 2017; 27:439-50. [PMID: 26871406 DOI: 10.1097/fbp.0000000000000219] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Chronic treatment with the dopamine D2/D3 agonist, quinpirole, or the serotonin 1A agonist, 8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT), induces behavioral sensitization. It is not known whether both drugs produce sensitization through a shared mechanism. Here, we examine whether quinpirole and 8-OH-DPAT show cross-sensitization and impact sensitization, as would be expected from shared mechanisms. Male rats (N=208) were assigned randomly to 16 groups formed by crossing four doses of quinpirole (0, 0.03125, 0.0625, or 0.125 mg/kg) with four doses of 8-OH-DPAT (0, 0.03125, 0.625, or 0.125 mg/kg). After a course of 10 drug treatments administered twice per week in locomotor activity chambers, all groups were challenged on separate tests with quinpirole (0.1 mg/kg), 8-OH-DPAT (0.1 mg/kg), or saline, and locomotor activity was evaluated. Challenge tests with quinpirole and 8-OHDPAT showed no cross-sensitization between the drugs. Chronic quinpirole (0.125 mg/kg) administration induced a sensitized quinpirole response that was attenuated dose-dependently by chronic 8-OH-DPAT cotreatment. Cotreatment with quinpirole (0.0625 mg/kg) and 8-OH-DPAT (all doses) induced quinpirole sensitization. Chronic 8-OH-DPAT (0.125 mg/kg) induced a sensitized 8-OHDPAT response that was prevented by chronic cotreatment with the lowest but not the highest dose of quinpirole. Cotreatment with 8-OHDPAT (0.0625) and quinpirole (0.125 mg/kg) induced sensitization to 8-OH-DPAT. The saline challenge test showed elevated locomotor activity in chronic quinpirole (0.125 mg/kg) and 8-OHDPAT (0.0625, 0.125 mg/kg) alone groups, and in seven of nine cotreated groups. The absence of cross-sensitization suggests separate mechanisms of sensitization to quinpirole and 8-OH-DPAT. Cotreatment effects suggest that induction of sensitization can be modulated by serotonin 1A and D2/D3 activity.
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d'Angelo C, Eagle DM, Coman CM, Robbins TW. Role of the medial prefrontal cortex and nucleus accumbens in an operant model of checking behaviour and uncertainty. Brain Neurosci Adv 2017; 1:2398212817733403. [PMID: 29900415 PMCID: PMC5990926 DOI: 10.1177/2398212817733403] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2017] [Accepted: 08/22/2017] [Indexed: 11/16/2022] Open
Abstract
Background: Excessive checking is a common, debilitating symptom of obsessive–compulsive
disorder. To further examine cognitive processes underpinning checking
behaviour, and clarify how and why checking develops, we designed a novel
operant paradigm for rats, the observing response task. The present study
used the observing response task to investigate checking behaviour following
excitotoxic lesions of the medial prefrontal cortex, nucleus accumbens core
and dorsal striatum, brain regions considered to be of relevance to
obsessive–compulsive disorder. Methods: In the observing response task, rats pressed an ‘observing’ lever for
information (provided by light onset) about the location of an ‘active’
lever that provided food reinforcement. Following training, rats received
excitotoxic lesions of the regions described above and performance was
evaluated post-operatively before histological processing. Results: Medial prefrontal cortex lesions selectively increased functional checking
with a less-prominent effect on non-functional checking and reduced
discrimination accuracy during light information periods. Rats with nucleus
accumbens core lesions made significantly more checking responses than
sham-lesioned rats, including both functional and non-functional checking.
Dorsal striatum lesions had no direct effect on checking per se, but reduced
both active and inactive lever presses, and therefore changed the relative
balance between checking responses and instrumental responses. Conclusions: These results suggest that the medial prefrontal cortex and nucleus accumbens
core are important in the control of checking, perhaps via their role in
processing uncertainty of reinforcement, and that dysfunction of these
regions may therefore promote excessive checking behaviour, possibly
relevant to obsessive-compulsive disorder.
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Affiliation(s)
- Camilla d'Angelo
- Department of Psychology, University of Cambridge, Cambridge, UK.,Behavioural and Clinical Neuroscience Institute (BCNI), University of Cambridge, Cambridge, UK
| | - Dawn M Eagle
- Department of Psychology, University of Cambridge, Cambridge, UK.,Behavioural and Clinical Neuroscience Institute (BCNI), University of Cambridge, Cambridge, UK
| | | | - Trevor W Robbins
- Department of Psychology, University of Cambridge, Cambridge, UK.,Behavioural and Clinical Neuroscience Institute (BCNI), University of Cambridge, Cambridge, UK
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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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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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