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Kim D, Yadav D, Song M. An updated review on animal models to study attention-deficit hyperactivity disorder. Transl Psychiatry 2024; 14:187. [PMID: 38605002 PMCID: PMC11009407 DOI: 10.1038/s41398-024-02893-0] [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: 11/01/2023] [Revised: 03/18/2024] [Accepted: 03/25/2024] [Indexed: 04/13/2024] Open
Abstract
Attention-deficit hyperactivity disorder (ADHD) is a neuropsychiatric disorder affecting both children and adolescents. Individuals with ADHD experience heterogeneous problems, such as difficulty in attention, behavioral hyperactivity, and impulsivity. Recent studies have shown that complex genetic factors play a role in attention-deficit hyperactivity disorders. Animal models with clear hereditary traits are crucial for studying the molecular, biological, and brain circuit mechanisms underlying ADHD. Owing to their well-managed genetic origins and the relative simplicity with which the function of neuronal circuits is clearly established, models of mice can help learn the mechanisms involved in ADHD. Therefore, in this review, we highlighting the important genetic animal models that can be used to study ADHD.
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Affiliation(s)
- Daegeon Kim
- Department of Life Science, Yeungnam University, Gyeongsan-si, South Korea
| | - Dhananjay Yadav
- Department of Life Science, Yeungnam University, Gyeongsan-si, South Korea
| | - Minseok Song
- Department of Life Science, Yeungnam University, Gyeongsan-si, South Korea.
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Regan SL, Williams MT, Vorhees CV. Review of rodent models of attention deficit hyperactivity disorder. Neurosci Biobehav Rev 2022; 132:621-637. [PMID: 34848247 PMCID: PMC8816876 DOI: 10.1016/j.neubiorev.2021.11.041] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 11/22/2021] [Accepted: 11/23/2021] [Indexed: 01/03/2023]
Abstract
Attention deficit hyperactivity disorder (ADHD) is a polygenic neurodevelopmental disorder that affects 8-12 % of children and >4 % of adults. Environmental factors are believed to interact with genetic predispositions to increase susceptibility to ADHD. No existing rodent model captures all aspects of ADHD, but several show promise. The main genetic models are the spontaneous hypertensive rat, dopamine transporter knock-out (KO) mice, dopamine receptor subtype KO mice, Snap-25 KO mice, guanylyl cyclase-c KO mice, and latrophilin-3 KO mice and rats. Environmental factors thought to contribute to ADHD include ethanol, nicotine, PCBs, lead (Pb), ionizing irradiation, 6-hydroxydopamine, neonatal hypoxia, some pesticides, and organic pollutants. Model validation criteria are outlined, and current genetic models evaluated against these criteria. Future research should explore induced multiple gene KOs given that ADHD is polygenic and epigenetic contributions. Furthermore, genetic models should be combined with environmental agents to test for interactions.
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Affiliation(s)
- Samantha L. Regan
- Neuroscience Graduate Program, University of Cincinnati, Cincinnati, OH 45229
| | - Michael T. Williams
- Department of Pediatrics, University of Cincinnati College of Medicine, and Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229
| | - Charles V. Vorhees
- Department of Pediatrics, University of Cincinnati College of Medicine, and Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229,Corresponding author: Charles V. Vorhees, Ph.D., Div. of Neurology, Cincinnati Children’s Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH 45229, USA:
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Uys MM, Shahid M, Harvey BH. Therapeutic Potential of Selectively Targeting the α 2C-Adrenoceptor in Cognition, Depression, and Schizophrenia-New Developments and Future Perspective. Front Psychiatry 2017; 8:144. [PMID: 28855875 PMCID: PMC5558054 DOI: 10.3389/fpsyt.2017.00144] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 07/24/2017] [Indexed: 12/12/2022] Open
Abstract
α2A- and α2C-adrenoceptors (ARs) are the primary α2-AR subtypes involved in central nervous system (CNS) function. These receptors are implicated in the pathophysiology of psychiatric illness, particularly those associated with affective, psychotic, and cognitive symptoms. Indeed, non-selective α2-AR blockade is proposed to contribute toward antidepressant (e.g., mirtazapine) and atypical antipsychotic (e.g., clozapine) drug action. Both α2C- and α2A-AR share autoreceptor functions to exert negative feedback control on noradrenaline (NA) release, with α2C-AR heteroreceptors regulating non-noradrenergic transmission (e.g., serotonin, dopamine). While the α2A-AR is widely distributed throughout the CNS, α2C-AR expression is more restricted, suggesting the possibility of significant differences in how these two receptor subtypes modulate regional neurotransmission. However, the α2C-AR plays a more prominent role during states of low endogenous NA activity, while the α2A-AR is relatively more engaged during states of high noradrenergic tone. Although augmentation of conventional antidepressant and antipsychotic therapy with non-selective α2-AR antagonists may improve therapeutic outcome, animal studies report distinct yet often opposing roles for the α2A- and α2C-ARs on behavioral markers of mood and cognition, implying that non-selective α2-AR antagonism may compromise therapeutic utility both in terms of efficacy and side-effect liability. Recently, several highly selective α2C-AR antagonists have been identified that have allowed deeper investigation into the function and utility of the α2C-AR. ORM-13070 is a useful positron emission tomography ligand, ORM-10921 has demonstrated antipsychotic, antidepressant, and pro-cognitive actions in animals, while ORM-12741 is in clinical development for the treatment of cognitive dysfunction and neuropsychiatric symptoms in Alzheimer's disease. This review will emphasize the importance and relevance of the α2C-AR as a neuropsychiatric drug target in major depression, schizophrenia, and associated cognitive deficits. In addition, we will present new prospects and future directions of investigation.
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Affiliation(s)
- Madeleine Monique Uys
- Division of Pharmacology, Centre of Excellence for Pharmaceutical Sciences, North-West University, Potchefstroom, South Africa
| | | | - Brian Herbert Harvey
- Division of Pharmacology, Centre of Excellence for Pharmaceutical Sciences, North-West University, Potchefstroom, South Africa
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Function of brain α2B-adrenergic receptor characterized with subtype-selective α2B antagonist and KO mice. Neuroscience 2016; 339:608-621. [DOI: 10.1016/j.neuroscience.2016.10.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 10/03/2016] [Accepted: 10/05/2016] [Indexed: 11/19/2022]
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Sallee FR. The Role of Alpha2-Adrenergic Agonists in Attention-Deficit/Hyperactivity Disorder. Postgrad Med 2015; 122:78-87. [DOI: 10.3810/pgm.2010.09.2204] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Floyd R. Sallee
- Department of Psychiatry, University of Cincinnati, Cincinnati, OH
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α₂- and β-adrenoceptors involvement in nortriptyline modulation of auditory sustained attention and impulsivity. Psychopharmacology (Berl) 2012; 222:237-45. [PMID: 22271065 DOI: 10.1007/s00213-012-2635-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Accepted: 01/01/2012] [Indexed: 10/14/2022]
Abstract
RATIONALE The catecholamine innervation of the prefrontal cortex controls attentional focus and inhibits inappropriate behavioral responses. The mechanism of action with which norepinephrine (NE) reuptake inhibitors modulate these cognitive functions has not been fully investigated. OBJECTIVE We investigated the effect of systemic administration of the NE reuptake blocker nortriptyline (NT) on attention and impulsivity using an auditory sustained attention task. The task was designed to assess impulsive behavior and the maintenance of attentional focus to an auditory stimulus presented at interresponse time durations (IRT) between 5 and 80 s. RESULTS NT (2.0 but not 3.0 mg/kg) improved sustained attention and decreased the percentage of premature responses without changing their latency. To better understand the adrenergic component of NT action, we tested the effect of noradrenergic receptor antagonists alone or together with NT. The α(2)-receptor antagonist yohimbine, the α(1)-receptor antagonist prazosin, or the β-receptor antagonist propranolol alone did not significantly affect attentive performance or premature responses. However, the beneficial effects of NT on sustained attention and premature responses were attenuated by pretreatment with either yohimbine or propranolol. On the contrary, prazosin did not affect the NT-mediated improvement in sustained attention. CONCLUSIONS We conclude that sustained attention displays an inverse U-shaped dependence on NT, mediated-at least in part-by α(2)- and β-adrenoceptors. We speculate that low doses of NT improve performance by maximizing the phasic release of NE, while higher doses of NT would elevate tonic levels of NE, thus producing suboptimal levels of phasically released NE.
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Gu L, Liu YJ, Wang YB, Yi LT. Role for monoaminergic systems in the antidepressant-like effect of ethanol extracts from Hemerocallis citrina. JOURNAL OF ETHNOPHARMACOLOGY 2012; 139:780-787. [PMID: 22197914 DOI: 10.1016/j.jep.2011.11.059] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Revised: 11/18/2011] [Accepted: 11/29/2011] [Indexed: 05/27/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Hemerocallis citrina, a traditional herbal medicine, has been used for the improvement of emotions in Eastern-Asia countries. AIM OF THE STUDY Herein, we explored the antidepressant-like effect and its monoaminergic mechanism of the ethanol extracts from Hemerocallis citrina (HCE). MATERIALS AND METHODS Effect of HCE (90, 180 and 360 mg/kg, p.o.) on the immobility time was assessed in the mouse forced swim test (FST) and tail suspension test (TST), and locomotor activity was evaluated in the open-field test (OFT). Additionally, the monoamine neurotransmitters serotonin (5-HT), noradrenaline (NA) and dopamine (DA) levels involved in the antidepressant-like effect of HCE were also measured in the mice brain regions of frontal cortex and hippocampus. RESULTS HCE (90, 180 and 360 mg/kg, p.o.) administration significantly reduced the immobility time in both the FST and TST without accompanying changes in locomotor activity in the OFT. The pretreatment of mice with WAY 100635 (0.1 mg/kg, s.c., a 5-HT(1A) receptor antagonist), cyproheptadine (3 mg/kg, i.p., a 5-HT(2) receptor antagonist), prazosin (62.5 μg/kg, i.p., an α(1)-adrenoceptor antagonist), yohimbine (1 mg/kg, i.p., an α(2)-adrenoceptor antagonist), propranolol (5 mg/kg, i.p., a β-adrenoceptor antagonist) or sulpiride (50 mg/kg, i.p., a dopamine D(2) receptor antagonist), but not SCH23390 (0.05 mg/kg, s.c., a dopamine D(1) receptor antagonist) prevented the antidepressant-like effect of HCE (360 mg/kg, p.o.) in the TST. In addition, HCE enhanced 5-HT and NA levels in the frontal cortex and hippocampus as well as elevated DA levels in the frontal cortex. CONCLUSION The results indicate that the antidepressant-like effect of HCE is dependent on the serotonergic (5-HT(1A) and 5-HT(2) receptors), noradrenergic (α(1)-, α(2)- and β-adrenoceptors) and dopaminergic (D(2) receptor) systems as well as the elevation of 5-HT, NA and DA levels in the mouse brain.
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Affiliation(s)
- Lan Gu
- Department of Chemical and Pharmaceutical Engineering, College of Chemical Engineering, Huaqiao University, Xiamen, Fujian Province, PR China
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Abstract
The neonatal 6-OHDA-lesioned rat, coloboma mouse, DAT-KO mouse, and spontaneously hypertensive rat (SHR) models all bear a phenotypic resemblance to ADHD in that they express hyperactivity, inattention, and/or impulsivity. The models also illustrate the heterogeneity of ADHD: the initial cause (chemical depletion or genetic abnormality) of the ADHD-like behaviors is different for each model. Neurochemical and behavioral studies of the models indicate aberrations in monoaminergic neurotransmission. Hyperdopaminergic neurotransmission is implicated in the abnormal behavior of all models. Norepinephrine has a dual enhancing/inhibitory role in ADHD symptoms, and serotonin acts to inhibit abnormal dopamine and norepinephrine signaling. It is unlikely that symptoms arise from a single neurotransmitter dysfunction. Rather, studies of animal models of ADHD suggest that symptoms develop through the complex interactions of monoaminergic neurotransmitter systems.
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Affiliation(s)
- Xueliang Fan
- Departments of Pharmacology and Neurology, Emory University School of Medicine, Atlanta, GA, 30322, USA
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Gunn RK, Keenan ME, Brown RE. Analysis of sensory, motor and cognitive functions of the coloboma (C3Sn.Cg-Cm/J) mutant mouse. GENES BRAIN AND BEHAVIOR 2011; 10:579-88. [PMID: 21507201 DOI: 10.1111/j.1601-183x.2011.00697.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The coloboma mutant mouse (C3Sn.Cg-Cm/J) has been proposed as an animal model of attention-deficit hyperactivity disorder (ADHD) because of excessive locomotion in the open field, yet few studies have looked at other behavioral measures in these mice. We analyzed activity levels of male and female Cm mice and their littermate controls (C3H) in two different types of open field, as well as their hearing (acoustic startle) and sensorimotor gating (prepulse inhibition), pain responsiveness (tail flick and hot plate), motor control (balance beam), motor learning (Rotarod), hippocampal working memory (spontaneous alternation in a Y-maze) and olfactory learning and memory (conditioned odor preference). We found hyperactivity and a lack of habituation in the small and large open fields and a deficit in prepulse inhibition in these mice, as well as a learning deficit in male Cm mice in conditioned odor preference but no deficits in pain perception or spontaneous alternation. Results from the rotarod and balance beam tasks indicate that Cm mice have severe motor co-ordination and balance problems compared to their C3H littermates, suggesting that Cm mice may be a more suitable model of ataxia than ADHD.
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Affiliation(s)
- R K Gunn
- Department of Psychology, Dalhousie University, 1459 Oxford Street, Halifax, Nova Scotia, Canada
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Russell VA. Overview of animal models of attention deficit hyperactivity disorder (ADHD). ACTA ACUST UNITED AC 2011; Chapter 9:Unit9.35. [PMID: 21207367 DOI: 10.1002/0471142301.ns0935s54] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Attention-deficit/hyperactivity disorder (ADHD) is a heterogeneous, highly heritable, behavioral disorder that affects ∼5% to 10% of children worldwide. Although animal models cannot truly reflect human psychiatric disorders, they can provide insight into the disorder that cannot be obtained from human studies because of the limitations of available techniques. Genetic models include the spontaneously hypertensive rat (SHR), the Naples High Excitability (NHE) rat, poor performers in the 5-choice serial reaction time (5-CSRT) task, the dopamine transporter (DAT) knock-out mouse, the SNAP-25 deficient mutant coloboma mouse, mice expressing a human mutant thyroid hormone receptor, a nicotinic receptor knock-out mouse, and a tachykinin-1 (NK1) receptor knock-out mouse. Chemically induced models of ADHD include prenatal or early postnatal exposure to ethanol, nicotine, polychlorinated biphenyls, or 6-hydroxydopamine (6-OHDA). Environmentally induced models have also been suggested; these include neonatal anoxia and rat pups reared in social isolation. The major insight provided by animal models was the consistency of findings regarding the involvement of dopaminergic, noradrenergic, and sometimes also serotonergic systems, as well as more fundamental defects in neurotransmission.
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Affiliation(s)
- Vivienne Ann Russell
- Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Observatory, South Africa
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Robertson HR, Feng G. Annual Research Review: Transgenic mouse models of childhood-onset psychiatric disorders. J Child Psychol Psychiatry 2011; 52:442-75. [PMID: 21309772 PMCID: PMC3075087 DOI: 10.1111/j.1469-7610.2011.02380.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Childhood-onset psychiatric disorders, such as attention deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD), mood disorders, obsessive compulsive spectrum disorders (OCSD), and schizophrenia (SZ), affect many school-age children, leading to a lower quality of life, including difficulties in school and personal relationships that persist into adulthood. Currently, the causes of these psychiatric disorders are poorly understood, resulting in difficulty diagnosing affected children, and insufficient treatment options. Family and twin studies implicate a genetic contribution for ADHD, ASD, mood disorders, OCSD, and SZ. Identification of candidate genes and chromosomal regions associated with a particular disorder provide targets for directed research, and understanding how these genes influence the disease state will provide valuable insights for improving the diagnosis and treatment of children with psychiatric disorders. Transgenic mouse models are one important approach in the study of human diseases, allowing for the use of a variety of experimental approaches to dissect the contribution of a specific chromosomal or genetic abnormality in human disorders. While it is impossible to model an entire psychiatric disorder in a single mouse model, these models can be extremely valuable in dissecting out the specific role of a gene, pathway, neuron subtype, or brain region in a particular abnormal behavior. In this review we discuss existing transgenic mouse models for childhood-onset psychiatric disorders. We compare the strength and weakness of various transgenic mouse models proposed for each of the common childhood-onset psychiatric disorders, and discuss future directions for the study of these disorders using cutting-edge genetic tools.
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Affiliation(s)
- Holly R. Robertson
- Duke University, Neurobiology Department Durham, N.C.,Massachusetts Institute of Technology, Brain and Cognitive Sciences Department Cambridge, M.A
| | - Guoping Feng
- Duke University, Neurobiology Department Durham, N.C.,Massachusetts Institute of Technology, Brain and Cognitive Sciences Department Cambridge, M.A
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Sontag TA, Tucha O, Walitza S, Lange KW. Animal models of attention deficit/hyperactivity disorder (ADHD): a critical review. ACTA ACUST UNITED AC 2010; 2:1-20. [DOI: 10.1007/s12402-010-0019-x] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2009] [Accepted: 01/02/2010] [Indexed: 01/04/2023]
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Cho SC, Kim JW, Kim BN, Hwang JW, Shin MS, Park M, Kim SA, Cho DY, Yoo HJ, Chung US, Son JW, Park TW. Association between the alpha-2C-adrenergic receptor gene and attention deficit hyperactivity disorder in a Korean sample. Neurosci Lett 2009; 446:108-11. [PMID: 18835330 DOI: 10.1016/j.neulet.2008.09.058] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2008] [Revised: 09/02/2008] [Accepted: 09/22/2008] [Indexed: 10/21/2022]
Abstract
Findings from preclinical and clinical research support the involvement of central noradrenergic dysregulation in the etiology of attention deficit hyperactivity disorder (ADHD). Previous studies have suggested that the alpha-2C-adrenergic receptor gene (ADRA2C) is associated with ADHD. The aims of this study were to examine the association between the ADRA2C (GT)n repeat polymorphism (STR marker adra2c1) and ADHD in a Korean sample. In this case-control and family-based association study, we assessed 184 ADHD probands, 150 normal controls, and 98 trios. There were no significant differences in the allele frequencies of the ADRA2C polymorphism between the ADHD and control groups (p > 0.05). The overall allele-wise transmission disequilibrium test (TDT) analysis showed statistical significance (chi2 = 19.07, p = 0.025). We found a trend for preferential transmission of the 183-bp allele (chi2 = 3.72, p = 0.054), and a significantly lower-than-expected rate of transmission of the 187-bp allele (chi2 = 6.26, p = 0.012). With regard to the temperament profiles of the Junior Temperament and Character Inventory (JTCI), the ADHD subjects with the 183/183 genotype at the ADRA2C polymorphism showed a trend toward a lower score in the Novelty Seeking (p = 0.020) profile than did those with the other genotypes. Our findings provide important evidence that the ADRA2C polymorphism is involved in the etiology of ADHD in Korean subjects. In addition, our results provide evidence that the temperament of Novelty Seeking and ADHD might share molecular genetic characteristics related to the noradrenergic system.
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Affiliation(s)
- Soo-Churl Cho
- Department of Child and Adolescent Psychiatry, College of Medicine, Seoul National University Hospital, 28 Yongon-Dong, Chongno-Gu, Seoul, Republic of Korea
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Patrick KS, Straughn AB, Perkins JS, González MA. Evolution of stimulants to treat ADHD: transdermal methylphenidate. Hum Psychopharmacol 2009; 24:1-17. [PMID: 19051222 PMCID: PMC2629554 DOI: 10.1002/hup.992] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVE The following comprehensive review describes the evolution of stimulant drug formulations used in the treatment of attention-deficit/hyperactivity disorder (ADHD). Emphasis is placed on the basic and clinical pharmacology of the dl-methylphenidate (MPH) transdermal system (MTS). METHODS The pharmacokinetic and pharmacodynamic literature pertaining to MPH and amphetamine enantiomers was reviewed in the context of ADHD therapy and MTS as a treatment option. RESULTS MTS incorporates MPH into an adhesive monolithic matrix, using the free base form of the drug to facilitate transdermal absorption. MTS technology minimizes contact dermatitis by eliminating to need for percutaneous penetration enhancers. After a lag time of approximately 2 h, plasma concentrations of the therapeutic d-MPH isomer become detectable, then continuously rise over the course of the recommended 9 h wear time. Concentrations of l-MPH typically attain 40-50% that of d-MPH (vs. 1-2% following oral MPH). Unauthorized MTS removal poses some misuse liability and over 50% of MTS drug content remains in the discarded system. CONCLUSIONS While liquid or chewable MPH formulations overcome potential swallowing difficulties, as do sprinkled once-daily extended-release (ER) MPH products, only MTS addresses swallowing difficulties while also offering a flexible individualized MPH exposure time in a once-daily MPH regimen.
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Affiliation(s)
- Kennerly S. Patrick
- Department of Pharmaceutical and Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, USA,Correspondence to: K. S. Patrick, 280 Calhoun St., QF221A, Medical University of South Carolina, Charleston, SC 29425−0742, USA. Tel: (843) 792−8429. Fax: (843) 792−1617. E-mail:
| | - Arthur B. Straughn
- Department of Pharmaceutical Sciences, University of Tennessee, Memphis, Tennessee, USA
| | - Jeb S. Perkins
- Department of Pharmaceutical and Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, USA
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Tilley MR, Gu HH. The effects of methylphenidate on knockin mice with a methylphenidate-resistant dopamine transporter. J Pharmacol Exp Ther 2008; 327:554-60. [PMID: 18698001 DOI: 10.1124/jpet.108.141713] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Methylphenidate (Ritalin) is one of the most commonly abused prescription drugs. It is a psychostimulant that inhibits the dopamine and norepinephrine transporters with high affinity. In mice, methylphenidate stimulates locomotor activity, is self-administered, and produces conditioned place preference, typical properties of an addictive drug. We have generated a knockin mouse line bearing a mutant dopamine transporter that is approximately 80-fold less sensitive to cocaine inhibition than wild type. It is interesting to note that this mutant is also almost 50-fold less sensitive to methylphenidate inhibition, suggesting similarities in the binding site for cocaine and methylphenidate. Because methylphenidate is not effective at inhibiting the mutant dopamine transporter, we hypothesized that it would not stimulate locomotor activity or produce reward in the knockin mice. In these knockin mice, doses up to 40 mg/kg methylphenidate either inhibit or fail to stimulate locomotor activity and do not produce conditioned place preference. Doses up to 40 mg/kg methylphenidate also fail to produce stereotypy in the knockin mice. Nisoxetine and desipramine, selective norepinephrine transporter inhibitors, also reduce locomotor activity in wild-type and knockin mice. These results indicate that enhanced dopaminergic neurotransmission is required for methylphenidate's stimulating and rewarding effects. In addition, we observed that drugs enhancing noradrenergic neurotransmission inhibit locomotor activity in mice, which is consistent with the notion that methylphenidate's ability to inhibit the norepinephrine transporter may contribute to its efficacy in treating attention deficit hyperactivity disorder.
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Affiliation(s)
- Michael R Tilley
- Department of Pharmacology, Ohio State University, Columbus, Ohio 43210, USA
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Fagerholm V, Rokka J, Nyman L, Sallinen J, Tiihonen J, Tupala E, Haaparanta M, Hietala J. Autoradiographic characterization of α2C-adrenoceptors in the human striatum. Synapse 2008; 62:508-15. [DOI: 10.1002/syn.20520] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Pharmacological models of ADHD. J Neural Transm (Vienna) 2007; 115:287-98. [PMID: 17994186 DOI: 10.1007/s00702-007-0826-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2007] [Accepted: 09/17/2007] [Indexed: 01/27/2023]
Abstract
For more than 50 years, heavy metal exposure during pre- or post-natal ontogeny has been known to produce long-lived hyperactivity in rodents. Global brain injury produced by neonatal hypoxia also produced hyperactivity, as did (mainly) hippocampal injury produced by ontogenetic exposure to X-rays, and (mainly) cerebellar injury produced by the ontogenetic treatments with the antimitotic agent methylazoxymethanol or with polychlorinated biphenyls (PCBs). More recently, ontogenetic exposure to nicotine has been implicated in childhood hyperactivity. Because attention deficits most often accompany the hyperactivity, all of the above treatments have been used as models of attention deficit hyperactivity disorder (ADHD). However, the causation of childhood hyperactivity remains unknown. Neonatal 6-OHDA-induced dopaminergic denervation of rodent forebrain also produces hyperactivity - and this model, or variations of it, remain the most widely-used animal model of ADHD. In all models, amphetamine (AMPH) and methylphenidate (MPH), standard treatments of childhood ADHD, typically attenuate the hyperactivity and/or attention deficit. On the basis of genetic models and the noted animal models, monoaminergic phenotypes appear to most-closely attend the behavioral dysfunctions, notably dopaminergic, noradrenergic and serotoninergic systems in forebrain (basal ganglia, nucleus accumbens, prefrontal cortex). This paper describes the various pharmacological models of ADHD and attempts to ascribe a neuronal phenotype with specific brain regions that may be associated with ADHD.
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Reprint of “Neurobiology of animal models of attention-deficit hyperactivity disorder”. J Neurosci Methods 2007; 166:I-XIV. [DOI: 10.1016/j.jneumeth.2006.12.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2006] [Revised: 12/04/2006] [Accepted: 12/14/2006] [Indexed: 11/22/2022]
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Russell VA. Neurobiology of animal models of attention-deficit hyperactivity disorder. J Neurosci Methods 2007; 161:185-98. [PMID: 17275916 DOI: 10.1016/j.jneumeth.2006.12.005] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2006] [Revised: 12/04/2006] [Accepted: 12/14/2006] [Indexed: 10/23/2022]
Abstract
Attention-deficit hyperactivity disorder (ADHD) is a heterogeneous, highly heritable, disorder resulting from complex gene-gene and gene-environment interactions. The defining symptoms of hyperactivity, impulsivity and impaired sustained attention are not unique to ADHD. It is therefore not surprising that animals with distinctly different neural defects model the behavioural characteristics of the disorder. Consistent with ADHD being a developmental disorder, animal models are either genetic (spontaneously hypertensive rats (SHR), dopamine transporter (DAT) knock-out mice, SNAP-25 mutant mice, mice expressing a mutant thyroid receptor) or have suffered an insult to the central nervous system during the early stages of development (anoxia, 6-hydroxydopamine). It appears that neural transmission is impaired by either direct disruption of dopaminergic transmission or a more general impairment of neurotransmission that gives rise to compensatory changes in monoaminergic systems that are not sufficient to completely normalize neural function. In general, results obtained with animal studies suggest that dopamine neurons are functionally impaired. However, evidence obtained from some animal models suggests that the noradrenergic and serotonergic neurotransmitter systems may be the target of drugs that ameliorate ADHD symptoms.
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Affiliation(s)
- Vivienne Ann Russell
- Department of Human Biology, University of Cape Town, Anzio Road, Observatory 7925, South Africa.
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van der Kooij MA, Glennon JC. Animal models concerning the role of dopamine in attention-deficit hyperactivity disorder. Neurosci Biobehav Rev 2007; 31:597-618. [PMID: 17316796 DOI: 10.1016/j.neubiorev.2006.12.002] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2006] [Revised: 10/22/2006] [Accepted: 12/30/2006] [Indexed: 11/29/2022]
Abstract
Several models of attention-deficit hyperactivity disorder (ADHD) have been proposed, ranging from administration of neurotoxins to genetically manipulated models. These models are used to gain insight into ADHD as a disorder and assist in the discovery of new therapeutic strategies. However, the information gained from these models differs, depending to a large extent on the validity (or otherwise) of the model. Thus the insights gained from these models with respect to the pathophysiology and aetiology of ADHD remains inconclusive. No animal model resembles the clinical situation of ADHD perfectly but good animal models of ADHD should mimic its characteristics, confirm to an underlying theory of ADHD and ultimately make predictions of future therapies. While the involvement of dopamine (DA) in ADHD has been established, the evaluation of rodent models of ADHD particularly with respect to dopaminergic systems is attempted here. It is concluded that the neonatal 6-hydroxy-dopamine lesioned rat and DA transporter knockout/knockdown mice have the highest degree of validity for ADHD.
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Affiliation(s)
- Michael A van der Kooij
- Laboratory for Psychoneuroimmunology & Department of Neonatology, University Medical Center Utrecht, Lundlaan 6, 3584EA Utrecht, The Netherlands.
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Mill J. Rodent models: utility for candidate gene studies in human attention-deficit hyperactivity disorder (ADHD). J Neurosci Methods 2007; 166:294-305. [PMID: 17234273 DOI: 10.1016/j.jneumeth.2006.11.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2006] [Revised: 11/30/2006] [Accepted: 11/30/2006] [Indexed: 11/18/2022]
Abstract
Attention-deficit hyperactivity disorder (ADHD) is a common neurobehavioral disorder defined by symptoms of developmentally inappropriate inattention, impulsivity and hyperactivity. Behavioral genetic studies provide overwhelming evidence for a significant genetic role in the pathogenesis of the disorder. Rodent models have proven extremely useful in helping understand more about the genetic basis of ADHD in humans. A number of well-characterized rodent models have been proposed, consisting of inbred strains, selected lines, genetic knockouts, and transgenic animals, which have been used to inform candidate gene studies in ADHD. In addition to providing information about the dysregulation of known candidate genes, rodents are excellent tools for the identification of novel ADHD candidate genes. While not yet widely used to identify genes for ADHD-like behaviors in rodents, quantitative trait loci (QTL) mapping approaches using recombinant inbred strains, heterogeneous stock mice, and chemically mutated animals have the potential to revolutionize our understanding of the genetic basis of ADHD.
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Affiliation(s)
- Jonathan Mill
- Centre for Addiction and Mental Health, Toronto, Canada.
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Fan X, Hess EJ. D2-like dopamine receptors mediate the response to amphetamine in a mouse model of ADHD. Neurobiol Dis 2006; 26:201-11. [PMID: 17291774 PMCID: PMC1876677 DOI: 10.1016/j.nbd.2006.12.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2006] [Revised: 12/05/2006] [Accepted: 12/20/2006] [Indexed: 11/16/2022] Open
Abstract
The mechanisms underlying the effects of psychostimulants in attention deficit hyperactivity disorder (ADHD) are not well understood, but indirect evidence implicates D2 dopamine receptors. Here we dissect the components of dopaminergic neurotransmission in the hyperactive mouse mutant coloboma to identify pre- and postsynaptic elements essential for the effects of amphetamine in these mice. Amphetamine treatment reduced locomotor activity in coloboma mice, but induced a robust increase in dopamine overflow suggesting that abnormal regulation of dopamine efflux does not account for the behavioral effect. However, the D2-like dopamine receptor antagonists haloperidol and raclopride, but not the D1-like dopamine receptor antagonist SCH23390, blocked the amphetamine-induced reduction in locomotor activity in coloboma mice, providing direct evidence that D2-like dopamine receptors mediate the effect of amphetamine in these mice. With the precedent established that it is possible to directly antagonize this response, this strategy should prove useful for identifying novel therapeutics in ADHD.
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Affiliation(s)
- Xueliang Fan
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287
| | - Ellen J. Hess
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21287
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