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Branca C, Bortolato M. The role of neuroactive steroids in tic disorders. Neurosci Biobehav Rev 2024; 160:105637. [PMID: 38519023 PMCID: PMC11121756 DOI: 10.1016/j.neubiorev.2024.105637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2023] [Revised: 03/03/2024] [Accepted: 03/19/2024] [Indexed: 03/24/2024]
Abstract
Tics are sudden, repetitive movements or vocalizations. Tic disorders, such as Tourette syndrome (TS), are contributed by the interplay of genetic risk factors and environmental variables, leading to abnormalities in the functioning of the cortico-striatal-thalamo-cortical (CSTC) circuitry. Various neurotransmitter systems, such as gamma-aminobutyric acid (GABA) and dopamine, are implicated in the pathophysiology of these disorders. Building on the evidence that tic disorders are predominant in males and exacerbated by stress, emerging research is focusing on the involvement of neuroactive steroids, including dehydroepiandrosterone sulfate (DHEAS) and allopregnanolone, in the ontogeny of tics and other phenotypes associated with TS. Emerging evidence indicates that DHEAS levels are significantly elevated in the plasma of TS-affected boys, and the clinical onset of this disorder coincides with the period of adrenarche, the developmental stage characterized by a surge in DHEAS synthesis. On the other hand, allopregnanolone has garnered particular attention for its potential to mediate the adverse effects of acute stress on the exacerbation of tic severity and frequency. Notably, both neurosteroids act as key modulators of GABA-A receptors, suggesting a pivotal role of these targets in the pathophysiology of various clinical manifestations of tic disorders. This review explores the potential mechanisms by which these and other neuroactive steroids may influence tic disorders and discusses the emerging therapeutic strategies that target neuroactive steroids for the management of tic disorders.
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Affiliation(s)
- Caterina Branca
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, UT, USA
| | - Marco Bortolato
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, UT, USA.
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Anderson CJ, Cadeddu R, Anderson DN, Huxford JA, VanLuik ER, Odeh K, Pittenger C, Pulst SM, Bortolato M. A novel naïve Bayes approach to identifying grooming behaviors in the force-plate actometric platform. J Neurosci Methods 2024; 403:110026. [PMID: 38029972 DOI: 10.1016/j.jneumeth.2023.110026] [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: 07/09/2023] [Revised: 10/27/2023] [Accepted: 11/24/2023] [Indexed: 12/01/2023]
Abstract
BACKGROUND Self-grooming behavior in rodents serves as a valuable behavioral index for investigating stereotyped and perseverative responses. Most current grooming analyses rely on video observation, which lacks standardization, efficiency, and quantitative information about force. To address these limitations, we developed an automated paradigm to analyze grooming using a force-plate actometer. NEW METHOD Grooming behavior is quantified by calculating ratios of relevant movement power spectral bands. These ratios are input into a naïve Bayes classifier, trained with manual video observations. The effectiveness of this method was tested using CIN-d mice, an animal model developed through early-life depletion of striatal cholinergic interneurons (CIN-d) and featuring prolonged grooming responses to acute stressors. Behavioral monitoring was simultaneously conducted on the force-place actometer and by video recording. RESULTS The naïve Bayes approach achieved 93.7% accurate classification and an area under the receiver operating characteristic curve of 0.894. We confirmed that male CIN-d mice displayed significantly longer grooming durations than controls. However, this elevation was not correlated with increases in grooming force. Notably, the dopaminergic antagonist haloperidol reduced grooming force and duration. COMPARISON WITH EXISTING METHODS In contrast to observation-based approaches, our method affords rapid, unbiased, and automated assessment of grooming duration, frequency, and force. CONCLUSIONS Our novel approach enables fast and accurate automated detection of grooming behaviors. This method holds promise for high-throughput assessments of grooming stereotypies in animal models of neuropsychiatric disorders.
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Affiliation(s)
- Collin J Anderson
- School of Medical Sciences, University of Sydney, Camperdown, Australia; School of Biomedical Engineering, University of Sydney, Camperdown, Australia; Department of Neurology, School of Medicine, University of Utah, Salt Lake City, UT, USA.
| | - Roberto Cadeddu
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, UT, USA
| | - Daria Nesterovich Anderson
- School of Biomedical Engineering, University of Sydney, Camperdown, Australia; Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, UT, USA; Department of Neurosurgery, School of Medicine, University of Utah, Salt Lake City, UT, USA
| | - Job A Huxford
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, UT, USA
| | - Easton R VanLuik
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, UT, USA
| | - Karen Odeh
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, UT, USA
| | - Christopher Pittenger
- Department of Psychiatry, School of Medicine, Yale University, New Haven, CT, USA; Department of Psychology, School of Arts and Sciences, Yale University, New Haven, CT, USA; Child Study Center, School of Medicine, Yale University, New Haven, CT, USA; Center for Brain and Mind Health, School of Medicine, Yale University, New Haven, CT, USA
| | - Stefan M Pulst
- Department of Neurology, School of Medicine, University of Utah, Salt Lake City, UT, USA
| | - Marco Bortolato
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, UT, USA.
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Cavanna AE, Purpura G, Riva A, Nacinovich R. Co-morbid tics and stereotypies: a systematic literature review. Neurol Sci 2024; 45:477-483. [PMID: 37775616 PMCID: PMC10791822 DOI: 10.1007/s10072-023-07095-y] [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: 03/18/2023] [Accepted: 09/24/2023] [Indexed: 10/01/2023]
Abstract
BACKGROUND Tics and stereotypies are childhood-onset repetitive behaviours that can pose significant diagnostic challenges in clinical practice. Both tics and stereotypies are characterised by a complex co-morbidity profile, however little is known about the co-occurrence of these hyperkinetic disorders in the same patient population. OBJECTIVE This review aimed to assess the relationship between tics and stereotypies when these conditions present in co-morbidity. METHODS We conducted a systematic literature review of original studies on co-morbid tics and stereotypies, according to the standards outlined in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. RESULTS Our literature search identified six studies of suitable sample size (n ≥ 40) presenting data on the association between tics and stereotypies in otherwise typically developing patients. A considerable proportion (23%) of patients diagnosed with stereotypic movement disorder present with co-morbid tics (range 18-43%). Likewise, the prevalence of primary stereotypies is increased in patients with tic disorders such as Tourette syndrome (8%, range 6-12%). DISCUSSION Tics and stereotypies can often develop in co-morbidity. The association of tics and stereotypies in the same patient has practical implications, in consideration of the different treatment approaches. Future research should focus on the assessment and management of both conditions, particularly in special populations (e.g. patients with pervasive developmental disorders).
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Affiliation(s)
- Andrea E Cavanna
- Department of Neuropsychiatry, National Centre for Mental Health, BSMHFT and University of Birmingham, 25 Vincent Drive, Birmingham, B15 2FG, UK.
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology and University College London, London, UK.
- School of Life and Health Sciences, Aston Brain Centre, Aston University, Birmingham, UK.
- School of Medicine and Surgery, University of Milano-Bicocca, Milan, Italy.
| | - Giulia Purpura
- School of Medicine and Surgery, University of Milano-Bicocca, Milan, Italy
| | - Anna Riva
- School of Medicine and Surgery, University of Milano-Bicocca, Milan, Italy
- Department of Child Neuropsychiatry, IRCCS San Gerardo dei Tintori, Monza, Italy
| | - Renata Nacinovich
- School of Medicine and Surgery, University of Milano-Bicocca, Milan, Italy
- Department of Child Neuropsychiatry, IRCCS San Gerardo dei Tintori, Monza, Italy
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Correia K, Walker R, Pittenger C, Fields C. A comparison of machine learning methods for quantifying self-grooming behavior in mice. Front Behav Neurosci 2024; 18:1340357. [PMID: 38347909 PMCID: PMC10859524 DOI: 10.3389/fnbeh.2024.1340357] [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: 11/17/2023] [Accepted: 01/10/2024] [Indexed: 02/15/2024] Open
Abstract
Background As machine learning technology continues to advance and the need for standardized behavioral quantification grows, commercial and open-source automated behavioral analysis tools are gaining prominence in behavioral neuroscience. We present a comparative analysis of three behavioral analysis pipelines-DeepLabCut (DLC) and Simple Behavioral Analysis (SimBA), HomeCageScan (HCS), and manual scoring-in measuring repetitive self-grooming among mice. Methods Grooming behavior of mice was recorded at baseline and after water spray or restraint treatments. Videos were processed and analyzed in parallel using 3 methods (DLC/SimBA, HCS, and manual scoring), quantifying both total number of grooming bouts and total grooming duration. Results Both treatment conditions (water spray and restraint) resulted in significant elevation in both total grooming duration and number of grooming bouts. HCS measures of grooming duration were significantly elevated relative to those derived from manual scoring: specifically, HCS tended to overestimate duration at low levels of grooming. DLC/SimBA duration measurements were not significantly different than those derived from manual scoring. However, both SimBA and HCS measures of the number of grooming bouts were significantly different than those derived from manual scoring; the magnitude and direction of the difference depended on treatment condition. Conclusion DLC/SimBA provides a high-throughput pipeline for quantifying grooming duration that correlates well with manual scoring. However, grooming bout data derived from both DLC/SimBA and HCS did not reliably estimate measures obtained via manual scoring.
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Affiliation(s)
- Kassi Correia
- Department of Psychiatry, Yale School of Medicine, Yale University, New Haven, CT, United States
| | - Raegan Walker
- Department of Psychiatry, Yale School of Medicine, Yale University, New Haven, CT, United States
| | | | - Christopher Fields
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, United States
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Cadeddu R, Van Zandt M, Santovito LS, Odeh K, Anderson CJ, Flanagan D, Nordkild P, Pinna G, Pittenger C, Bortolato M. Prefrontal allopregnanolone mediates the adverse effects of acute stress in a mouse model of tic pathophysiology. Neuropsychopharmacology 2023; 48:1288-1299. [PMID: 37198434 PMCID: PMC10354086 DOI: 10.1038/s41386-023-01603-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Revised: 04/24/2023] [Accepted: 05/05/2023] [Indexed: 05/19/2023]
Abstract
Ample evidence suggests that acute stress can worsen symptom severity in Tourette syndrome (TS); however, the neurobiological underpinnings of this phenomenon remain poorly understood. We previously showed that acute stress exacerbates tic-like and other TS-associated responses via the neurosteroid allopregnanolone (AP) in an animal model of repetitive behavioral pathology. To verify the relevance of this mechanism to tic pathophysiology, here we tested the effects of AP in a mouse model recapitulating the partial depletion of dorsolateral cholinergic interneurons (CINs) seen in post-mortem studies of TS. Mice underwent targeted depletion of striatal CINs during adolescence and were tested in young adulthood. Compared with controls, partially CIN-depleted male mice exhibited several TS-relevant abnormalities, including deficient prepulse inhibition (PPI) and increased grooming stereotypies after a 30-min session of spatial confinement - a mild acute stressor that increases AP levels in the prefrontal cortex (PFC). These effects were not seen in females. Systemic and intra-PFC AP administration dose-dependently worsened grooming stereotypies and PPI deficits in partially CIN-depleted males. Conversely, both AP synthesis inhibition and pharmacological antagonism reduced the effects of stress. These results further suggest that AP in the PFC mediates the adverse effects of stress on the severity of tics and other TS-related manifestations. Future studies will be necessary to confirm these mechanisms in patients and define the circuitry responsible for the effects of AP on tics.
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Affiliation(s)
- Roberto Cadeddu
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, UT, USA
| | - Meghan Van Zandt
- Department of Psychiatry, School of Medicine, Yale University, New Haven, CT, USA
| | - Luca Spiro Santovito
- The Psychiatric Institute, Department of Psychiatry, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Karen Odeh
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, UT, USA
| | - Collin J Anderson
- Department of Neurology, School of Medicine, University of Utah, Salt Lake City, UT, USA
- School of Medical Sciences, University of Sydney, Camperdown, NSW, Australia
- School of Biomedical Engineering, University of Sydney, Camperdown, NSW, Australia
| | - Deirdre Flanagan
- Department of Psychiatry, School of Medicine, Yale University, New Haven, CT, USA
| | | | - Graziano Pinna
- The Psychiatric Institute, Department of Psychiatry, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
- UI Center on Depression and Resilience (UICDR), Department of Psychiatry, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
- Center for Alcohol Research in Epigenetics (CARE), Department of Psychiatry, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Christopher Pittenger
- Department of Psychiatry, School of Medicine, Yale University, New Haven, CT, USA.
- Department of Psychology, School of Arts and Sciences, Yale University, New Haven, CT, USA.
- Child Study Center, School of Medicine, Yale University, New Haven, CT, USA.
- Center for Brain and Mind Health, School of Medicine, Yale University, New Haven, CT, USA.
| | - Marco Bortolato
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, UT, USA.
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Nabinger DD, Altenhofen S, Buatois A, Facciol A, Peixoto JV, da Silva JMK, Chatterjee D, Rübensam G, Gerlai R, Bonan CD. Acute administration of a dopamine D2/D3 receptor agonist alters behavioral and neural parameters in adult zebrafish. Prog Neuropsychopharmacol Biol Psychiatry 2023; 125:110753. [PMID: 36934998 DOI: 10.1016/j.pnpbp.2023.110753] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 01/30/2023] [Accepted: 03/15/2023] [Indexed: 03/21/2023]
Abstract
The dopaminergic neurotransmitter system is implicated in several brain functions and behavioral processes. Alterations in it are associated with the pathogenesis of several human neurological disorders. Pharmacological agents that interact with the dopaminergic system allow the investigation of dopamine-mediated cellular and molecular responses and may elucidate the biological bases of such disorders. Zebrafish, a translationally relevant biomedical research organism, has been successfully employed in prior psychopharmacology studies. Here, we evaluated the effects of quinpirole (dopamine D2/D3 receptor agonist) in adult zebrafish on behavioral parameters, brain-derived neurotrophic factor (BDNF) and neurotransmitter levels. Zebrafish received intraperitoneal injections of 0.5, 1.0, or 2.0 mg/kg quinpirole or saline (control group) twice with an inter-injection interval of 48 h. All tests were performed 24 h after the second injection. After this acute quinpirole administration, zebrafish exhibited decreased locomotor activity, increased anxiety-like behaviors and memory impairment. However, quinpirole did not affect social and aggressive behavior. Quinpirole-treated fish exhibited stereotypic swimming, characterized by repetitive behavior followed by immobile episodes. Moreover, quinpirole treatment also decreased the number of BDNF-immunoreactive cells in the zebrafish brain. Analysis of neurotransmitter levels demonstrated a significant increase in glutamate and a decrease in serotonin, while no alterations were observed in dopamine. These findings demonstrate that dopaminergic signaling altered by quinpirole administration results in significant behavioral and neuroplastic changes in the central nervous system of zebrafish. Thus, we conclude that the use of quinpirole administration in adult zebrafish may be an appropriate tool for the analysis of mechanisms underlying neurological disorders related to the dopaminergic system.
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Affiliation(s)
- Débora Dreher Nabinger
- Laboratório de Neuroquímica e Psicofarmacologia, Programa de Pós-Graduação em Biologia Celular e Molecular, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Stefani Altenhofen
- Laboratório de Neuroquímica e Psicofarmacologia, Programa de Pós-Graduação em Biologia Celular e Molecular, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil; Programa de Pós-Graduação em Medicina e Ciências da Saúde, Escola de Medicina, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Alexis Buatois
- Department of Psychology, University of Toronto Mississauga, ON, Canada
| | - Amanda Facciol
- Department of Psychology, University of Toronto Mississauga, ON, Canada
| | - Julia Vasconcellos Peixoto
- Laboratório de Neuroquímica e Psicofarmacologia, Programa de Pós-Graduação em Biologia Celular e Molecular, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Julia Maria Kuhl da Silva
- Laboratório de Neuroquímica e Psicofarmacologia, Programa de Pós-Graduação em Biologia Celular e Molecular, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | | | - Gabriel Rübensam
- Centro de Pesquisa em Toxicologia e Farmacologia (INTOX), Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Robert Gerlai
- Department of Psychology, University of Toronto Mississauga, ON, Canada
| | - Carla Denise Bonan
- Laboratório de Neuroquímica e Psicofarmacologia, Programa de Pós-Graduação em Biologia Celular e Molecular, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil; Programa de Pós-Graduação em Medicina e Ciências da Saúde, Escola de Medicina, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil; Instituto Nacional de Ciência e Tecnologia em Doenças Cerebrais, Excitotoxicidade e Neuroproteção, Porto Alegre, RS, Brazil.
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The Sapap3 -/- mouse reconsidered as a comorbid model expressing a spectrum of pathological repetitive behaviours. Transl Psychiatry 2023; 13:26. [PMID: 36717540 PMCID: PMC9886949 DOI: 10.1038/s41398-023-02323-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 12/30/2022] [Accepted: 01/17/2023] [Indexed: 01/31/2023] Open
Abstract
Symptom comorbidity is present amongst neuropsychiatric disorders with repetitive behaviours, complicating clinical diagnosis and impeding appropriate treatments. This is of particular importance for obsessive-compulsive disorder (OCD) and Tourette syndrome. Here, we meticulously analysed the behaviour of Sapap3 knockout mice, the recent rodent model predominantly used to study compulsive-like behaviours, and found that its behaviour is more complex than originally and persistently described. Indeed, we detected previously unreported elements of distinct pathologically repetitive behaviours, which do not form part of rodent syntactic cephalo-caudal self-grooming. These repetitive behaviours include sudden, rapid body and head/body twitches, resembling tic-like movements. We also observed that another type of repetitive behaviour, aberrant hindpaw scratching, might be responsible for the flagship-like skin lesions of this mouse model. In order to characterise the symptomatological nature of observed repetitive behaviours, we pharmacologically challenged these phenotypes by systemic aripiprazole administration, a first-line treatment for tic-like symptoms in Tourette syndrome and trichotillomania. A single treatment of aripiprazole significantly reduced the number of head/body twitches, scratching, and single-phase grooming, but not syntactic grooming events. These observations are in line with the high comorbidity of tic- and compulsive-like symptoms in Tourette, OCD and trichotillomania patients.
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Bortolato M, Coffey BJ, Gabbay V, Scheggi S. Allopregnanolone: The missing link to explain the effects of stress on tic exacerbation? J Neuroendocrinol 2022; 34:e13022. [PMID: 34423500 PMCID: PMC8800948 DOI: 10.1111/jne.13022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 07/19/2021] [Accepted: 07/26/2021] [Indexed: 12/13/2022]
Abstract
The neurosteroid allopregnanolone (3α-hydroxy-5α-pregnan-20-one; AP) elicits pleiotropic effects in the central nervous system, ranging from neuroprotective and anti-inflammatory functions to the regulation of mood and emotional responses. Several lines of research show that the brain rapidly produces AP in response to acute stress to reduce the allostatic load and enhance coping. These effects not only are likely mediated by GABAA receptor activation but also result from the contributions of other mechanisms, such as the stimulation of membrane progesterone receptors. In keeping with this evidence, AP has been shown to exert rapid, potent antidepressant properties and has been recently approved for the therapy of moderate-to-severe postpartum depression. In addition to depression, emerging evidence points to the potential of AP as a therapy for other neuropsychiatric disorders, including anxiety, seizures, post-traumatic stress disorder and cognitive problems. Although this evidence has spurred interest in further therapeutic applications of AP, some investigations suggest that this neurosteroid may also be associated with adverse events in specific disorders. For example, our group has recently documented that AP increases tic-like manifestations in several animal models of tic disorders; furthermore, our results indicate that inhibiting AP synthesis and signalling reduces the exacerbation of tic severity associated with acute stress. Although the specific mechanisms of these effects remain partially elusive, our findings point to the possibility that the GABAergic activation by AP may also lead to disinhibitory effects, which could interfere with the ability of patients to suppress their tics. Future studies will be necessary to verify whether these mechanisms may apply to other externalising manifestations, such as impulse-control problems and manic symptoms.
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Affiliation(s)
- Marco Bortolato
- Department of Pharmacology and ToxicologyCollege of PharmacyUniversity of UtahSalt Lake CityUTUSA
- Research Consortium on NeuroEndocrine Causes of Tics (ReConNECT)
| | - Barbara J. Coffey
- Research Consortium on NeuroEndocrine Causes of Tics (ReConNECT)
- Department of Psychiatry and Behavioral ScienceMiller School of MedicineUniversity of MiamiMiamiFLUSA
| | - Vilma Gabbay
- Research Consortium on NeuroEndocrine Causes of Tics (ReConNECT)
- Department of Psychiatry and Behavioral SciencesAlbert Einstein College of MedicineBronxNYUSA
| | - Simona Scheggi
- Department of Molecular and Developmental MedicineSchool of MedicineUniversity of SienaSienaItaly
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Nabinger DD, Altenhofen S, Peixoto JV, da Silva JMK, Bonan CD. Long-lasting behavioral effects of quinpirole exposure on zebrafish. Neurotoxicol Teratol 2021; 88:107034. [PMID: 34600099 DOI: 10.1016/j.ntt.2021.107034] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 09/25/2021] [Accepted: 09/26/2021] [Indexed: 01/11/2023]
Abstract
The human brain matures into a complex structure, and to reach its complete development, connections must occur along exact paths. If at any stage, the processes are altered, interrupted, or inhibited, the consequences can be permanent. Dopaminergic signaling participates in the control of physiological functions and behavioral processes, and alterations in this signaling pathway are related to the pathogenesis of several neurological disorders. For this reason, the use of pharmacological agents able to interact with the dopaminergic signaling may elucidate the biological bases of such disorders. We investigated the long-lasting behavioral effects on adult zebrafish after quinpirole (a dopamine D2/D3 receptor agonist) exposure during early life stages of development (24 h exposure at 5 days post-fertilization, dpf) to better understand the mechanisms underlying neurological disorders related to the dopaminergic system. Quinpirole exposure at the early life stages of zebrafish led to late behavioral alterations. When evaluated at 120 dpf, zebrafish presented increased anxiety-like behaviors. At the open tank test, fish remained longer at the bottom of the tank, indicating anxiety-like behavior. Furthermore, quinpirole-treated fish exhibited increased absolute turn angle, likely an indication of elevated erratic movements and a sign of increased fear or anxiety. Quinpirole-treated fish also showed altered swimming patterns, characterized by stereotypic swimming. During the open tank test, exposed zebrafish swims from corner to corner in a repetitive manner at the bottom of the tank. Moreover, quinpirole exposure led to memory impairment compared to control fish. However, quinpirole administration had no effects on social and aggressive behavior. These findings demonstrate that dopaminergic signaling altered by quinpirole administration in the early life stages of development led to late alterations in behavioral parameters of adult zebrafish.
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Affiliation(s)
- Debora Dreher Nabinger
- Laboratório de Neuroquímica e Psicofarmacologia, Programa de Pós-Graduação em Biologia Celular e Molecular, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Stefani Altenhofen
- Laboratório de Neuroquímica e Psicofarmacologia, Programa de Pós-Graduação em Biologia Celular e Molecular, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil; Programa de Pós-Graduação em Medicina e Ciências da Saúde, Escola de Medicina, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Julia Vasconcellos Peixoto
- Laboratório de Neuroquímica e Psicofarmacologia, Programa de Pós-Graduação em Biologia Celular e Molecular, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Julia Maria Kuhl da Silva
- Laboratório de Neuroquímica e Psicofarmacologia, Programa de Pós-Graduação em Biologia Celular e Molecular, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Carla Denise Bonan
- Laboratório de Neuroquímica e Psicofarmacologia, Programa de Pós-Graduação em Biologia Celular e Molecular, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil; Programa de Pós-Graduação em Medicina e Ciências da Saúde, Escola de Medicina, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil; Instituto Nacional de Ciência e Tecnologia em Doenças Cerebrais, Excitotoxicidade e Neuroproteção, Porto Alegre, RS, Brazil.
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Nabinger DD, Altenhofen S, Peixoto JV, da Silva JMK, Gerlai R, Bonan CD. Feeding status alters exploratory and anxiety-like behaviors in zebrafish larvae exposed to quinpirole. Prog Neuropsychopharmacol Biol Psychiatry 2021; 108:110179. [PMID: 33212194 DOI: 10.1016/j.pnpbp.2020.110179] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 11/11/2020] [Accepted: 11/12/2020] [Indexed: 01/09/2023]
Abstract
The dysfunction of dopaminergic signaling is associated with several neurological disorders. The use of pharmacological agents that interact with this signaling system may be employed to understand mechanisms underlying such disorders. Nutritional status can impact dopamine reuptake, receptor affinity, transporter activity, and the effects of drugs that bind to dopamine receptors or interact with dopaminergic system. Here we evaluated the effects of quinpirole (a dopamine D2/D3 receptor agonist) exposure on fed and non-fed zebrafish larvae. Zebrafish larvae (6 days post-fertilization, dpf) were exposed to quinpirole (5.5, 16.7, and 50.0 μM) or water (control group) for one hour. To evaluate the effect of feeding status on quinpirole exposure, the experiments were performed on fed and non-fed animals, a between subject experimental design. Both fed and non-fed quinpirole treated larvae exhibited increased erratic movements compared to controls in an open tank exploration task. No alterations were observed on the main parameters of exploratory behavior and swim activity for non-fed larvae treated with quinpirole compared to controls. However, fed animals exposed to quinpirole exhibited increased locomotor activity, anxiety-like behavior, and repetitive circular movements when compared to controls and non-fed exposed animals. In addition, we observed quinpirole exposure to have no effects on morphological parameters and heartbeat, but to impair optomotor responses in both fed and non-fed larvae compared to control. We also found quinpirole effects to interact with feeding status, as quinpirole-treated fed larvae improved while quinpirole treated non-fed larvae impaired their avoidance reaction towards an aversive stimulus. These results indicate that the behavioral effects of quinpirole exposure depended upon feeding status. They showed that consumption of food, a naturally rewarding stimulus known to engage the dopaminergic system, made this neurotransmitter system more susceptible to quinpirole's effects.
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Affiliation(s)
- Débora Dreher Nabinger
- Laboratório de Neuroquímica e Psicofarmacologia, Programa de Pós-Graduação em Biologia Celular e Molecular, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Stefani Altenhofen
- Laboratório de Neuroquímica e Psicofarmacologia, Programa de Pós-Graduação em Biologia Celular e Molecular, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil; Programa de Pós-Graduação em Medicina e Ciências da Saúde, Escola de Medicina, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Júlia Vasconcellos Peixoto
- Laboratório de Neuroquímica e Psicofarmacologia, Programa de Pós-Graduação em Biologia Celular e Molecular, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Julia Maria Kuhl da Silva
- Laboratório de Neuroquímica e Psicofarmacologia, Programa de Pós-Graduação em Biologia Celular e Molecular, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Robert Gerlai
- Department of Psychology, University of Toronto Mississauga, ON, Canada
| | - Carla Denise Bonan
- Laboratório de Neuroquímica e Psicofarmacologia, Programa de Pós-Graduação em Biologia Celular e Molecular, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil; Programa de Pós-Graduação em Medicina e Ciências da Saúde, Escola de Medicina, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil; Instituto Nacional de Ciência e Tecnologia em Doenças Cerebrais, Excitotoxicidade e Neuroproteção, Porto Alegre, RS, Brazil.
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The α6 GABA A Receptor Positive Allosteric Modulator DK-I-56-1 Reduces Tic-Related Behaviors in Mouse Models of Tourette Syndrome. Biomolecules 2021; 11:biom11020175. [PMID: 33525455 PMCID: PMC7912006 DOI: 10.3390/biom11020175] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/26/2021] [Accepted: 01/26/2021] [Indexed: 12/22/2022] Open
Abstract
Tourette syndrome (TS) is a disabling neurodevelopmental disorder characterized by multiple, recurrent tics. The pharmacological treatment of TS is currently based on dopaminergic antagonists; however, these drugs are associated with extrapyramidal symptoms and other serious adverse events. Recent evidence suggests that positive allosteric modulators (PAMs) of GABAA receptors containing α6 subunits (α6 GABAARs) oppose the behavioral effects of dopamine. Building on this evidence, in the present study, we tested the efficacy of DK-I-56-1, a highly selective PAM for α6 GABAARs, in mouse models of TS exhibiting tic-related responses. DK-I-56-1 significantly reduced tic-like jerks and prepulse inhibition (PPI) deficits in D1CT-7 transgenic mice, a well-documented mouse model of TS. DK-I-56-1 also prevented the exacerbation of spontaneous eyeblink reflex induced by the potent dopamine D1 receptor agonist SKF 82958, a proxy for tic-like responses. We also showed that both systemic and prefrontal cortical administration of DK-I-56-1 countered the PPI disruption caused by SKF 82958. Although the effects of DK-I-56-1 were akin to those elicited by dopaminergic antagonists, this drug did not elicit extrapyramidal effects, as measured by catalepsy. These results point to α6 GABAAR PAMs as promising TS therapies with a better safety profile than dopaminergic antagonists.
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Abstract
Effective pharmacological and psychotherapeutic treatments are well established for obsessive-compulsive disorder (OCD). Serotonin reuptake inhibitors (SRIs) are first-line treatment and are of benefit to about half of patients. Augmentation of SRI treatment with low-dose neuroleptics is an evidence-based second-line strategy. Specialty psychotherapy is also used as both first-line and second-line treatment and can benefit many. However, a substantial number of patients do not respond to these treatments. New alternatives are urgently needed. This review summarizes evidence for these established pharmacotherapeutic strategies, and for others that have been investigated in refractory disease but are not supported by the same level of evidence. We focus on three neurotransmitter systems in the brain: serotonin, dopamine, and glutamate. We summarize evidence from genetic, neuroimaging, animal model, and other lines of investigation that probe these three systems in patients with OCD. We also review recent work on predictors of response to current treatments. While many studies suggest abnormalities that may provide insight into the pathophysiology of the disorder, most studies have been small, and non-replication of reported findings has been common. Nevertheless, the gradual accrual of evidence for neurotransmitter dysregulation may in time lead the way to new pharmacological strategies.
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Cadeddu R, Bäckström T, Floris G, Nordkild P, Segerdahl M, Bortolato M. Isoallopregnanolone reduces tic-like behaviours in the D1CT-7 mouse model of Tourette syndrome. J Neuroendocrinol 2020; 32:e12754. [PMID: 31175669 DOI: 10.1111/jne.12754] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 05/16/2019] [Accepted: 06/04/2019] [Indexed: 12/29/2022]
Abstract
Tourette syndrome (TS) is a neuropsychiatric disorder characterised by multiple, persistent tics. These semi-voluntary motor and phonic manifestations are typically aggravated by exposure to acute stress, yet the mechanisms underlying this exacerbation remain unclear. Using a well-characterised animal model of TS, the D1CT-7 mouse, we recently showed that acute stress increases tic-like responses and causes sensorimotor gating deficits, as measured by the prepulse inhibition of the startle. We showed that these effects are promoted by the brain synthesis of the neurosteroid allopregnanolone (AP). In line with this idea, inhibition of AP synthesis by finasteride was found to suppress the tic-exacerbating effects of stress; conversely, AP administration resulted in a marked enhancement of the number of tic-like motor bursts. Given that the primary mechanism of AP is based on the positive allosteric modulation of GABAA receptors, in the present study, we hypothesised that the enhancement in tic-like behaviours induced by either stress or AP may be countered by isoallopregnanolone (isoAP), the natural 3β-epimer of AP that acts as an antagonist to the AP-binding site within GABAA receptors. In agreement with our hypothesis, isoAP (5-10 mg kg-1 , s.c.) dose-dependently reduced the number of tic-like behaviours induced by stress in D1CT-7 mice. These effects were comparable to those elicited by both the benchmark TS therapy haloperidol (0.3 mg kg-1 , i.p.), as well as finasteride (25 mg kg-1 , i.p.). IsoAP also countered the prepulse inhibition deficits secondary to stress in D1CT-7 mice. Finally, isoAP opposed the enhancement of tic-like behaviours induced by AP (15 mg kg-1 , i.p.). Given that isoAP is well-tolerated and has an optimal safety profile, these data suggest that this steroid may have therapeutic properties in TS.
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Affiliation(s)
- Roberto Cadeddu
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, UT, USA
| | - Torbjörn Bäckström
- Department of Clinical Sciences, Obstetrics and Gynecology, Umeå University, Umeå, Sweden
- Asarina Pharma, Copenhagen, Denmark
| | - Gabriele Floris
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, UT, USA
| | | | | | - Marco Bortolato
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, UT, USA
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Pittenger C. The histidine decarboxylase model of tic pathophysiology: a new focus on the histamine H 3 receptor. Br J Pharmacol 2019; 177:570-579. [PMID: 30714121 DOI: 10.1111/bph.14606] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 12/12/2018] [Accepted: 01/07/2019] [Indexed: 12/16/2022] Open
Abstract
Histamine dysregulation was implicated as a rare cause of Tourette syndrome and other tic disorders a decade ago by a landmark genetic study in a high density family pedigree, which implicated a hypomorphic mutation in the histidine decarboxylase (Hdc) gene as a rare but high penetrance genetic cause. Studies in Hdc knockout (KO) mice have confirmed that this mutation causes tic-relevant behavioural and neurochemical abnormalities that parallel what is seen in patients and thus validate the KO as a potentially informative model of tic pathophysiology. Recent studies have focused on the potential role of the histamine H3 receptor in this model, and by association in tic disorders and related neuropsychiatric conditions. The H3 receptor is up-regulated in the striatum in Hdc KO mice. As the H3 receptor has constitutive activity in the absence of ligand, this receptor up-regulation may have significant cellular effects despite the absence of neurotransmitter histamine in these mice. Activation in vivo of H3 receptors in wild type mice regulates signalling in striatal medium spiny neurons (MSNs) that interacts non-linearly with dopamine receptor signalling. Baseline signalling alterations in MSNs in Hdc KO mice resemble those seen after H3 receptor agonist treatment in wild type animals. H3 receptor agonist treatment in the KOs further accentuates most of these signalling abnormalities and produces behavioural stereotypy. Together, these data suggest the intriguing hypothesis that constitutive signalling by up-regulated H3 receptors explains many of the molecular and behavioural abnormalities seen in these animals. LINKED ARTICLES: This article is part of a themed section on New Uses for 21st Century. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.3/issuetoc.
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Nespoli E, Rizzo F, Boeckers T, Schulze U, Hengerer B. Altered dopaminergic regulation of the dorsal striatum is able to induce tic-like movements in juvenile rats. PLoS One 2018; 13:e0196515. [PMID: 29698507 PMCID: PMC5919623 DOI: 10.1371/journal.pone.0196515] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 04/13/2018] [Indexed: 01/01/2023] Open
Abstract
Motor tics are sudden, repetitive, involuntary movements representing the hallmark behaviors of the neurodevelopmental disease Tourette’s syndrome (TS). The primary cause of TS remains unclear. The initial observation that dopaminergic antagonists alleviate tics led to the development of a dopaminergic theory of TS etiology which is supported by post mortem and in vivo studies indicating that non-physiological activation of the striatum could generate tics. The striatum controls movement execution through the balanced activity of dopamine receptor D1 and D2-expressing medium spiny neurons of the direct and indirect pathway, respectively. Different neurotransmitters can activate or repress striatal activity and among them, dopamine plays a major role. In this study we introduced a chronic dopaminergic alteration in juvenile rats, in order to modify the delicate balance between direct and indirect pathway. This manipulation was done in the dorsal striatum, that had been associated with tic-like movements generation in animal models. The results were movements resembling tics, which were categorized and scored according to a newly developed rating scale and were reduced by clonidine and riluzole treatment. Finally, post mortem analyses revealed altered RNA expression of dopaminergic receptors D1 and D2, suggesting an imbalanced dopaminergic regulation of medium spiny neuron activity as being causally related to the observed phenotype.
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Affiliation(s)
- Ester Nespoli
- CNS Department, Boehringer Ingelheim Pharma GmbH& Co. KG, Biberach an der Riss, Germany
- Department of Child and Adolescent Psychiatry/Psychotherapy, University of Ulm, Ulm, Germany
- * E-mail: (BH); (EN)
| | - Francesca Rizzo
- Department of Child and Adolescent Psychiatry/Psychotherapy, University of Ulm, Ulm, Germany
- Institute of Anatomy and Cell Biology, University of Ulm, Ulm, Germany
| | - Tobias Boeckers
- Institute of Anatomy and Cell Biology, University of Ulm, Ulm, Germany
| | - Ulrike Schulze
- Department of Child and Adolescent Psychiatry/Psychotherapy, University of Ulm, Ulm, Germany
| | - Bastian Hengerer
- CNS Department, Boehringer Ingelheim Pharma GmbH& Co. KG, Biberach an der Riss, Germany
- * E-mail: (BH); (EN)
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Santangelo A, Bortolato M, Mosher LJ, Crescimanno G, Di Giovanni G, Cassioli E, Ricca V, Casarrubea M. Behavioral fragmentation in the D1CT-7 mouse model of Tourette's syndrome. CNS Neurosci Ther 2018; 24:703-711. [PMID: 29314714 DOI: 10.1111/cns.12789] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 11/29/2017] [Accepted: 12/01/2017] [Indexed: 12/14/2022] Open
Abstract
AIM The transgenic D1CT-7 mouse is one of the best-characterized animal models of Tourette's syndrome (TS), exhibiting spontaneous tic-like Head-Body Twitches (HBT) and deficits in sensorimotor gating. This study is aimed at evaluating the behavioral dynamics of these mutants and their potential relevance to TS. METHODS The behavior of D1CT-7 and Wild Type littermates was firstly assessed by considering frequencies and durations. To detect recurrent real-time behavioral sequences, the multivariate T-pattern analysis was employed. Analyses of transition probabilities among behaviors further provided an overall picture of the behavioral dynamics. RESULTS T-patterns and transition matrices revealed in D1CT-7 mice a clear-cut hyperactivity compared to controls, with a lower behavioral organization and a marked shift from cautious sniffing toward locomotion. Moreover, the behavioral patterns of the transgenic mice were pervasively disturbed by intrusive tic-like HBT leading to a marked fragmentation of the behavior. Novel exposure to open field provoked a transient inhibitory control over the disrupting phenotype. CONCLUSION The results of this study show that the D1CT-7 mouse model is subjected to a behavioral fragmentation, with repercussions going beyond the simple tic-like phenomenon. These phenotypes are strikingly akin to behavioral problems observed in patients with TS and further validate the power of this model in summarizing pivotal behavioral aspects of TS.
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Affiliation(s)
- Andrea Santangelo
- Psychiatry Unit, Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Florence, Italy
| | - Marco Bortolato
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT, USA
| | - Laura J Mosher
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT, USA.,Department of Pharmacology and Toxicology, University of Kansas, Lawrence, KS, USA
| | - Giuseppe Crescimanno
- Laboratory of Behavioral Physiology, Department of Experimental Biomedicine and Clinical Neurosciences, Human Physiology Section, University of Palermo, Palermo, Italy
| | - Giuseppe Di Giovanni
- Faculty of Medicine and Surgery, Department of Physiology and Biochemistry, University of Malta, Msida, Malta
| | - Emanuele Cassioli
- Psychiatry Unit, Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Florence, Italy
| | - Valdo Ricca
- Psychiatry Unit, Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Florence, Italy
| | - Maurizio Casarrubea
- Laboratory of Behavioral Physiology, Department of Experimental Biomedicine and Clinical Neurosciences, Human Physiology Section, University of Palermo, Palermo, Italy
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Histamine modulation of the basal ganglia circuitry in the development of pathological grooming. Proc Natl Acad Sci U S A 2017; 114:6599-6604. [PMID: 28584117 DOI: 10.1073/pnas.1704547114] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Aberrant histaminergic function has been proposed as a cause of tic disorders. A rare mutation in the enzyme that produces histamine (HA), histidine decarboxylase (HDC), has been identified in patients with Tourette syndrome (TS). Hdc knockout mice exhibit repetitive behavioral pathology and neurochemical characteristics of TS, establishing them as a plausible model of tic pathophysiology. Where, when, and how HA deficiency produces these effects has remained unclear: whether the contribution of HA deficiency to pathogenesis is acute or developmental, and where in the brain the relevant consequences of HA deficiency occur. Here, we address these key pathophysiological questions, using anatomically and cellularly targeted manipulations in mice. We report that specific ablation or chemogenetic silencing of histaminergic neurons in the tuberomammillary nucleus (TMN) of the hypothalamus leads to markedly elevated grooming, a form of repetitive behavioral pathology, and to elevated markers of neuronal activity in both dorsal striatum and medial prefrontal cortex. Infusion of HA directly into the striatum reverses this behavioral pathology, confirming that acute HA deficiency mediates the effect. Bidirectional chemogenetic regulation reveals that dorsal striatum neurons activated after TMN silencing are both sufficient to produce repetitive behavioral pathology and necessary for the full expression of the effect. Chemogenetic activation of TMN-regulated medial prefrontal cortex neurons, in contrast, increases locomotion and not grooming. These data confirm the centrality of striatal regulation by neurotransmitter HA in the adult in the production of pathological grooming.
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