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Dafny N, Claussen C, Frazier E, Liu Y. Differential Roles of Key Brain Regions: Ventral Tegmental Area, Locus Coeruleus, Dorsal Raphe, Nucleus Accumbens, Caudate Nucleus, and Prefrontal Cortex in Regulating Response to Methylphenidate: Insights from Neuronal and Behavioral Studies in Freely Behaving Rats. Int J Mol Sci 2024; 25:5938. [PMID: 38892125 PMCID: PMC11173053 DOI: 10.3390/ijms25115938] [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: 02/21/2024] [Revised: 05/20/2024] [Accepted: 05/21/2024] [Indexed: 06/21/2024] Open
Abstract
A total of 3102 neurons were recorded before and following acute and chronic methylphenidate (MPD) administration. Acute MPD exposure elicits mainly increases in neuronal and behavioral activity in dose-response characteristics. The response to chronic MPD exposure, as compared to acute 0.6, 2.5, or 10.0 mg/kg MPD administration, elicits electrophysiological and behavioral sensitization in some animals and electrophysiological and behavioral tolerance in others when the neuronal recording evaluations were performed based on the animals' behavioral responses, or amount of locomotor activity, to chronic MPD exposure. The majority of neurons recorded from those expressing behavioral sensitization responded to chronic MPD with further increases in firing rate as compared to the initial MPD responses. The majority of neurons recorded from animals expressing behavioral tolerance responded to chronic MPD with decreases in their firing rate as compared to the initial MPD exposures. Each of the six brain areas studied-the ventral tegmental area, locus coeruleus, dorsal raphe, nucleus accumbens, prefrontal cortex, and caudate nucleus (VTA, LC, DR, NAc, PFC, and CN)-responds significantly (p < 0.001) differently to MPD, suggesting that each one of the above brain areas exhibits different roles in the response to MPD. Moreover, this study demonstrates that it is essential to evaluate neuronal activity responses to psychostimulants based on the animals' behavioral responses to acute and chronic effects of the drug from several brain areas simultaneously to obtain accurate information on each area's role in response to the drug.
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Affiliation(s)
- Nachum Dafny
- Department of Neurobiology and Anatomy, McGovern Medical School, University of Texas Health Science Center, 6431 Fannin Street, Houston, TX 77030, USA; (C.C.); (Y.L.)
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Yuan A, Claussen C, Jones Z, Tang B, Dafny N. Methylphenidate induces a different response in the dorsal raphe as compared to ventral tegmental area and locus coeruleus: behavioral and concomitant neuronal recordings in adult rats. J Neural Transm (Vienna) 2023; 130:1579-1599. [PMID: 37391573 DOI: 10.1007/s00702-023-02665-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 06/13/2023] [Indexed: 07/02/2023]
Abstract
Methylphenidate (MPD) is a psychostimulant used to treat attention deficit hyperactivity disorder. MPD exerts its neurocognitive effects through increasing concentrations of dopamine (DA), norepinephrine (NE), and serotonin (5-HT) in the neuronal synapse. This study recorded from adult freely behaving rats a total of 1170 neurons, 403 from the ventral tegmental area (VTA), 409 from locus coeruleus (LC), and 356 from dorsal raphe (DR) nucleus, which are the main sources of DA, NE, and 5-HT to the mesocorticolimbic circuitry, respectively. Electrophysiological and behavioral activities were recorded simultaneously following acute and repetitive (chronic) saline or 0.6, 2.5, or 10.0 mg/kg MPD. The uniqueness of this study is the evaluation of neuronal activity based on the behavioral response to chronic MPD. Animals received daily saline or MPD administration on experimental days 1-6 (ED1-6), followed by a 3-day wash-out period, and then MPD rechallenge on ED10. Each chronic MPD dose elicits behavioral sensitization in some animals, while in others, behavioral tolerance. Neuronal excitation following chronic MPD was observed in brains areas of animals exhibiting behavioral sensitization, while neuronal attenuation following chronic MPD was observed in those animals expressing behavioral tolerance. DR neuronal activity was most affected in response to acute and chronic MPD administration and responded differently compared to the neurons recorded from VTA and LC neurons at all doses. This suggests that although not directly related, DR and 5-HT are involved in the acute and chronic effects of MPD in adult rats, but exhibit a different role in response to MPD.
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Affiliation(s)
- Anthony Yuan
- Department of Neurobiology and Anatomy, McGovern Medical School at University of Texas Health Sciences Center, 6431 Fannin Street, MSB 7.208, Houston, TX, 77030-2501, USA
| | - Catherine Claussen
- Department of Neurobiology and Anatomy, McGovern Medical School at University of Texas Health Sciences Center, 6431 Fannin Street, MSB 7.208, Houston, TX, 77030-2501, USA
| | - Zachary Jones
- Department of Neurobiology and Anatomy, McGovern Medical School at University of Texas Health Sciences Center, 6431 Fannin Street, MSB 7.208, Houston, TX, 77030-2501, USA
| | - Bin Tang
- Department of Neurobiology and Anatomy, McGovern Medical School at University of Texas Health Sciences Center, 6431 Fannin Street, MSB 7.208, Houston, TX, 77030-2501, USA
| | - Nachum Dafny
- Department of Neurobiology and Anatomy, McGovern Medical School at University of Texas Health Sciences Center, 6431 Fannin Street, MSB 7.208, Houston, TX, 77030-2501, USA.
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Verhein JR, Vyas S, Shenoy KV. Methylphenidate modulates motor cortical dynamics and behavior. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.15.562405. [PMID: 37905157 PMCID: PMC10614820 DOI: 10.1101/2023.10.15.562405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Methylphenidate (MPH, brand: Ritalin) is a common stimulant used both medically and non-medically. Though typically prescribed for its cognitive effects, MPH also affects movement. While it is known that MPH noncompetitively blocks the reuptake of catecholamines through inhibition of dopamine and norepinephrine transporters, a critical step in exploring how it affects behavior is to understand how MPH directly affects neural activity. This would establish an electrophysiological mechanism of action for MPH. Since we now have biologically-grounded network-level hypotheses regarding how populations of motor cortical neurons plan and execute movements, there is a unique opportunity to make testable predictions regarding how systemic MPH administration - a pharmacological perturbation - might affect neural activity in motor cortex. To that end, we administered clinically-relevant doses of MPH to Rhesus monkeys as they performed an instructed-delay reaching task. Concomitantly, we measured neural activity from dorsal premotor and primary motor cortex. Consistent with our predictions, we found dose-dependent and significant effects on reaction time, trial-by-trial variability, and movement speed. We confirmed our hypotheses that changes in reaction time and variability were accompanied by previously established population-level changes in motor cortical preparatory activity and the condition-independent signal that precedes movements. We expected changes in speed to be a result of changes in the amplitude of motor cortical dynamics and/or a translation of those dynamics in activity space. Instead, our data are consistent with a mechanism whereby the neuromodulatory effect of MPH is to increase the gain and/or the signal-to-noise of motor cortical dynamics during reaching. Continued work in this domain to better understand the brain-wide electrophysiological mechanism of action of MPH and other psychoactive drugs could facilitate more targeted treatments for a host of cognitive-motor disorders.
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Affiliation(s)
- Jessica R Verhein
- Medical Scientist Training Program, Stanford School of Medicine, Stanford University, Stanford, CA
- Neurosciences Graduate Program, Stanford School of Medicine, Stanford University, Stanford, CA
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA
- Current affiliations: Psychiatry Research Residency Training Program, University of California, San Francisco, San Francisco, CA
| | - Saurabh Vyas
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA
- Department of Bioengineering, Stanford University, Stanford, CA
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY
| | - Krishna V Shenoy
- Neurosciences Graduate Program, Stanford School of Medicine, Stanford University, Stanford, CA
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA
- Department of Bioengineering, Stanford University, Stanford, CA
- Department of Electrical Engineering, Stanford University, Stanford, CA
- Howard Hughes Medical Institute at Stanford University, Stanford, CA
- Department of Neurobiology, Stanford University, Stanford, CA
- Bio-X Program, Stanford University, Stanford, CA
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Pulido LN, Pochapski JA, Sugi A, Esaki JY, Stresser JL, Sanchez WN, Baltazar G, Levcik D, Fuentes R, Da Cunha C. Pre-clinical evidence that methylphenidate increases motivation and/or reward preference to search for high value rewards. Behav Brain Res 2023; 437:114065. [PMID: 36037842 DOI: 10.1016/j.bbr.2022.114065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 08/04/2022] [Accepted: 08/16/2022] [Indexed: 11/25/2022]
Abstract
Methylphenidate is a stimulant used to treat attention deficit and hyperactivity disorder (ADHD). In the last decade, illicit use of methylphenidate has increased among healthy young adults, who consume the drug under the assumption that it will improve cognitive performance. However, the studies that aimed to assess the methylphenidate effects on memory are not consistent. Here, we tested whether the effect of methylphenidate on a spatial memory task can be explained as a motivational and/or a reward effect. We tested the effects of acute and chronic i.p. administration of 0.3, 1 or 3 mg/kg of methylphenidate on motivation, learning and memory by using the 8-arm radial maze task. Adult male Wistar rats learned that 3 of the 8 arms of the maze were consistently baited with 1, 3, or 6 sucrose pellets, and the number of entries and reentries into reinforced and non-reinforced arms of the maze were scored. Neither acute nor chronic (20 days) methylphenidate treatment affected the number of entries in the non-baited arms. However, chronic, but not acute, 1-3 mg/kg methylphenidate increased the number of reentries in the higher reward arms, which suggests a motivational/rewarding effect rather than a working memory deficit. In agreement with this hypothesis, the methylphenidate treatment also decreased the approach latency to the higher reward arms, increased the approach latency to the low reward arm, and increased the time spent in the high, but not low, reward arm. These findings suggest that methylphenidate may act more as a motivational enhancer rather than a cognitive enhancer in healthy people.
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Affiliation(s)
- Laura N Pulido
- Laboratorio de Fisiologia e Farmacologia do Sistema Nervoso Central, Department of Pharmacology, Universidade Federal do Parana, Curitiba, Brazil
| | - Jose A Pochapski
- Laboratorio de Fisiologia e Farmacologia do Sistema Nervoso Central, Department of Pharmacology, Universidade Federal do Parana, Curitiba, Brazil; Department of Biochemistry, Universidade Federal do Parana, Curitiba, Brazil
| | - Adam Sugi
- Laboratorio de Fisiologia e Farmacologia do Sistema Nervoso Central, Department of Pharmacology, Universidade Federal do Parana, Curitiba, Brazil; Department of Biochemistry, Universidade Federal do Parana, Curitiba, Brazil
| | - Julie Y Esaki
- Laboratorio de Fisiologia e Farmacologia do Sistema Nervoso Central, Department of Pharmacology, Universidade Federal do Parana, Curitiba, Brazil
| | - Joao L Stresser
- Laboratorio de Fisiologia e Farmacologia do Sistema Nervoso Central, Department of Pharmacology, Universidade Federal do Parana, Curitiba, Brazil
| | - William N Sanchez
- Laboratorio de Fisiologia e Farmacologia do Sistema Nervoso Central, Department of Pharmacology, Universidade Federal do Parana, Curitiba, Brazil; Department of Biochemistry, Universidade Federal do Parana, Curitiba, Brazil; Integrative Neurobiology Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, MD, USA
| | - Gabriel Baltazar
- Laboratorio de Fisiologia e Farmacologia do Sistema Nervoso Central, Department of Pharmacology, Universidade Federal do Parana, Curitiba, Brazil; Department of Biochemistry, Universidade Federal do Parana, Curitiba, Brazil
| | - David Levcik
- Laboratory of Neurophysiology of Memory, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Romulo Fuentes
- Departamento de Neurociencias, Facultad de Medicina, Universidad de Chile, Santiago de Chile, Chile
| | - Claudio Da Cunha
- Laboratorio de Fisiologia e Farmacologia do Sistema Nervoso Central, Department of Pharmacology, Universidade Federal do Parana, Curitiba, Brazil; Department of Biochemistry, Universidade Federal do Parana, Curitiba, Brazil.
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Prolonged Longitudinal Transcutaneous Auricular Vagus Nerve Stimulation Effect on Striatal Functional Connectivity in Patients with Major Depressive Disorder. Brain Sci 2022; 12:brainsci12121730. [PMID: 36552189 PMCID: PMC9776392 DOI: 10.3390/brainsci12121730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 12/11/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Transcutaneous auricular vagus nerve stimulation (taVNS) is effective for treating major depressive disorder (MDD). We aimed to explore the modulating effect of prolonged longitudinal taVNS on the striatal subregions' functional connectivity (FC) in MDD patients. METHODS Sixteen MDD patients were enrolled and treated with taVNS for 8 weeks. Sixteen healthy control subjects (HCs) were recruited without intervention. The resting-state FC (rsFC) based on striatal subregion seed points and the Hamilton Depression Scale (HAMD) were evaluated in the MDD patients and HCs at baseline and after 8 weeks. A two-way ANCOVA test was performed on each rsFC metric to obtain the (group-by-time) interactions. RESULTS The rsFC values between the left ventral caudate (vCa) and right ventral prefrontal cortex (vPFC), and between the right nucleus accumbens (NAc) and right dorsal medial prefrontal cortex (dmPFC) and ventrolateral prefrontal cortex (vlPFC) are lower in the MDD patients compared to the HCs at baseline, and increase following taVNS; the rsFC values between the left vCa and right, superior occipital gyrus (SOG), and between the left dorsal caudate (dCa) and right cuneus are higher in MDD patients and decrease following taVNS. CONCLUSIONS Prolonged longitudinal taVNS can modulate the striatum rsFC with the prefrontal cortex, occipital cortex, temporal cortex, and intra-striatum, and these changes partly underlie any symptomatic improvements. The results indicate that prolonged longitudinal taVNS may produce beneficial treatment effects by modulating the cortical striatum circuitry in patients with MDD.
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Fang Y, Sun Y, Liu Y, Liu T, Hao W, Liao Y. Neurobiological mechanisms and related clinical treatment of addiction: a review. PSYCHORADIOLOGY 2022; 2:180-189. [PMID: 38665277 PMCID: PMC10917179 DOI: 10.1093/psyrad/kkac021] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 11/29/2022] [Accepted: 11/30/2022] [Indexed: 04/28/2024]
Abstract
Drug addiction or substance use disorder (SUD), has been conceptualized as a three-stage (i.e. binge/intoxication, withdrawal/negative affect, and preoccupation/anticipation/craving) recurring cycle that involves complex changes in neuroplasticity, reward, motivation, desire, stress, memory, and cognitive control, and other related brain regions and brain circuits. Neuroimaging approaches, including magnetic resonance imaging, have been key to mapping neurobiological changes correlated to complex brain regions of SUD. In this review, we highlight the neurobiological mechanisms of these three stages of addiction. The abnormal activity of the ventral tegmental, nucleus accumbens, and caudate nucleus in the binge/intoxication stage involve the reward circuit of the midbrain limbic system. The changes in the orbitofrontal cortex, dorsolateral prefrontal cortex, amygdala, and hypothalamus emotional system in the withdrawal/negative affect stage involve increases in negative emotional states, dysphoric-like effects, and stress-like responses. The dysregulation of the insula and prefrontal lobes is associated with craving in the anticipation stage. Then, we review the present treatments of SUD based on these neuroimaging findings. Finally, we conclude that SUD is a chronically relapsing disorder with complex neurobiological mechanisms and multimodal stages, of which the craving stage with high relapse rate may be the key element in treatment efficacy of SUD. Precise interventions targeting different stages of SUD and characteristics of individuals might serve as a potential therapeutic strategy for SUD.
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Affiliation(s)
- Yehong Fang
- Department of Psychiatry, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, 3 East Qingchun Road, Hangzhou, Zhejiang 310016, China
| | - Yunkai Sun
- Department of Psychiatry, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, 3 East Qingchun Road, Hangzhou, Zhejiang 310016, China
| | - Yi Liu
- Department of Psychiatry, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, 3 East Qingchun Road, Hangzhou, Zhejiang 310016, China
| | - Tieqiao Liu
- Department of Psychiatry & Mental Health Institute of the Second Xiangya Hospital, Central South University. National Clinical Research Center on Mental Disorders & National Technology Institute on Mental Disorders. Hunan Key Laboratory of Psychiatry and Mental Health, 139 Renmin (M) Rd, Changsha, Hunan 410011, P. R. China
| | - Wei Hao
- Department of Psychiatry & Mental Health Institute of the Second Xiangya Hospital, Central South University. National Clinical Research Center on Mental Disorders & National Technology Institute on Mental Disorders. Hunan Key Laboratory of Psychiatry and Mental Health, 139 Renmin (M) Rd, Changsha, Hunan 410011, P. R. China
| | - Yanhui Liao
- Department of Psychiatry, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, 3 East Qingchun Road, Hangzhou, Zhejiang 310016, China
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Consequences of Acute or Chronic Methylphenidate Exposure Using Ex Vivo Neurochemistry and In Vivo Electrophysiology in the Prefrontal Cortex and Striatum of Rats. Int J Mol Sci 2022; 23:ijms23158588. [PMID: 35955717 PMCID: PMC9369023 DOI: 10.3390/ijms23158588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 07/29/2022] [Accepted: 08/01/2022] [Indexed: 01/27/2023] Open
Abstract
Methylphenidate (MPH) is among the main drugs prescribed to treat patients with attention-deficit and hyperactivity disease (ADHD). MPH blocks both the norepinephrine and dopamine reuptake transporters (NET and DAT, respectively). Our study was aimed at further understanding the mechanisms by which MPH could modulate neurotransmitter efflux, using ex vivo radiolabelled neurotransmitter assays isolated from rats. Here, we observed significant dopamine and norepinephrine efflux from the prefrontal cortex (PFC) after MPH (100 µM) exposure. Efflux was mediated by both dopamine and norepinephrine terminals. In the striatum, MPH (100 µM) triggered dopamine efflux through both sodium- and vesicular-dependent mechanisms. Chronic MPH exposure (4 mg/kg/day/animal, voluntary oral intake) for 15 days, followed by a 28-day washout period, increased the firing rate of PFC pyramidal neurons, assessed by in vivo extracellular single-cell electrophysiological recordings, without altering the responses to locally applied NMDA, via micro-iontophoresis. Furthermore, chronic MPH treatment resulted in decreased efficiency of extracellular dopamine to modulate NMDA-induced firing activities of medium spiny neurons in the striatum, together with lower MPH-induced (100 µM) dopamine outflow, suggesting desensitization to both dopamine and MPH in striatal regions. These results indicate that MPH can modulate neurotransmitter efflux in brain regions enriched with dopamine and/or norepinephrine terminals. Further, long-lasting alterations of striatal and prefrontal neurotransmission were observed, even after extensive washout periods. Further studies will be needed to understand the clinical implications of these findings.
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Yuan A, King N, Kharas N, Yang P, Dafny N. The effect of environment on cross-sensitization between methylphenidate and amphetamine in female rats. Physiol Behav 2022; 252:113845. [PMID: 35594929 DOI: 10.1016/j.physbeh.2022.113845] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 04/22/2022] [Accepted: 05/15/2022] [Indexed: 11/17/2022]
Abstract
Methylphenidate (MPD) and amphetamine (AMP) are both psychostimulants that are often used to treat behavioral disorders. More recently, it has also been increasingly used illicitly for recreation as well as to improve intellectual performance. Many factors such as age, gender, genetic background, and environment govern the development of behavioral sensitization to MPD and cross-sensitization with other drugs, which are experimental behavioral markers indicating potential of substance dependence and abuse. This study examines the effects of the environment and age when MPD was exposed in adulthood alone as well as in adolescence into adulthood on cross-sensitization with AMP in female SD rats by randomizing animals to either receive the drug in a home cage or a test cage during adolescence, adulthood, or both. In a 34 day experiment, 16 groups of animals starting in adolescence were treated with saline on experimental day one (ED1), followed by a 6 day (ED2-ED7) treatment with either saline, 0.6 mg/kg AMP, 0.6, 2.5, or 10.0 mg/kg MPD. Experimental groups were then subject to a 3-day washout period (ED8-ED10) and then a retreatment with the respective drug on ED11 in adolescence (P-38 to P-49). Experiments continued in the same animal groups now in adulthood (P-60) with a saline treatment (ED1), followed by the same sequence of treatments in adolescence (ED2-ED11;P-61 to P-69). A rechallenge with the same AMP or MPD dose was performed on ED11 (P-70) followed by a single exposure to 0.6 mg/kg AMP on ED12 (P-71) to assess for cross sensitization between MPD and AMP. Animals treated with MPD in both adolescence and adulthood and in the last experimental day of AMP (ED12) showed higher intensity of cross-sensitivity between MPD and AMP as compared to animals treated with MPD only in adulthood. AMP and MPD treatment in adolescence and into adulthood in the home or test cage resulted in significantly higher responses to the drug as compared to those treated only in adulthood. Overall, we conclude that environmental alteration and adolescent exposure to MPD appeared to increase the risk of cross-sensitization to AMP in female SD rats i.e, using MPD in adolescence may increase the probability of becoming dependent on drugs of abuse. This further indicates that age, sex, and environment all influence the response to MPD and AMP, and further work is needed to elucidate the risks associated with MPD and AMP use.
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Affiliation(s)
- Anthony Yuan
- Department of Neurobiology and Anatomy, University of Texas Health at the McGovern Medical School, 6431 Fannin Street, MSB 7.208, Houston, TX 77030, United States
| | - Nicholas King
- Department of Neurobiology and Anatomy, University of Texas Health at the McGovern Medical School, 6431 Fannin Street, MSB 7.208, Houston, TX 77030, United States
| | - Natasha Kharas
- Department of Neurobiology and Anatomy, University of Texas Health at the McGovern Medical School, 6431 Fannin Street, MSB 7.208, Houston, TX 77030, United States
| | - Pamela Yang
- Department of Neurobiology and Anatomy, University of Texas Health at the McGovern Medical School, 6431 Fannin Street, MSB 7.208, Houston, TX 77030, United States
| | - Nachum Dafny
- Department of Neurobiology and Anatomy, University of Texas Health at the McGovern Medical School, 6431 Fannin Street, MSB 7.208, Houston, TX 77030, United States.
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Medina AC, Kabani A, Reyes-Vasquez C, Dafny N. Age differences to methylphenidate-NAc neuronal and behavioral recordings from freely behaving animals. J Neural Transm (Vienna) 2022; 129:1061-1076. [PMID: 35842551 DOI: 10.1007/s00702-022-02526-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 06/21/2022] [Indexed: 10/17/2022]
Abstract
Methylphenidate (MPD) is a psychostimulant that is widely prescribed to treat attention deficit-hyperactivity disorder, but it is abused recreationally as well. The nucleus accumbens (NAc) is part of the motivation circuit implicated in drug-seeking behaviors. The NAc neuronal activity was recorded alongside the behavioral activity from young and adult rats to determine if there are significant differences in the response to MPD. The same dose of MPD elicits behavioral sensitization in some animals and behavioral tolerance in others. In adult animals, higher doses of MPD resulted in a greater ratio of tolerance/sensitization. Animals who responded to chronic MPD with behavioral sensitization usually exhibited further increases in their NAc neuronal firing rates as well. Different upregulations of transcription factors (ΔFOSB/CREB), variable proportions of D1/D2 dopamine receptors, and modulation from other brain areas may predispose certain animals to express behavioral and neuronal sensitization versus tolerance to MPD.
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Affiliation(s)
- A C Medina
- Department of Neurobiology and Anatomy, University of Texas McGovern Medical School, Houston, TX, USA
| | - A Kabani
- Department of Neurobiology and Anatomy, University of Texas McGovern Medical School, Houston, TX, USA
| | - C Reyes-Vasquez
- Department of Neurobiology and Anatomy, University of Texas McGovern Medical School, Houston, TX, USA
| | - N Dafny
- Department of Neurobiology and Anatomy, University of Texas McGovern Medical School, Houston, TX, USA.
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Adolescent rats respond differently to methylphenidate as compared to adult rats- concomitant VTA neuronal and behavioral Recordings. Brain Res Bull 2022; 183:1-12. [PMID: 35202752 DOI: 10.1016/j.brainresbull.2022.02.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 01/20/2022] [Accepted: 02/17/2022] [Indexed: 01/09/2023]
Abstract
Methylphenidate (MPD) is the most widely prescribed psychostimulant used in adolescents and adults to treat attention-deficit/hyperactivity disorder (ADHD). The recreational use of MPD is becoming more prevalent because of its ability to improve cognitive enhancement. The ventral tegmental area (VTA) of the brain is highly associated with reward, cognition and addiction to drugs including psychostimulants like MPD. The VTA neuronal activity was recorded alongside the horizontal behavioral activity from freely behaving non-anesthetized rats. Four adolescent and four adult groups were treated with either saline, 0.6, 2.5 or 10.0 mg/kg MPD. In both adolescent and adult animals, the animals responded to MPD in a dose-dependent manner, such that as the dose of MPD increased, more animals and more VTA unit responded to the drug. The same doses of MPD elicited in some animals behavioral and neuronal sensitization and in other animals behavioral and neuronal tolerance. In the 0.6 and 10.0 mg/kg MPD dose groups there were significant differences between the age groups for how many animals expressed behavioral sensitization and behavioral tolerance to chronic MPD exposure. Additionally, the animal's behavioral response to MPD by excitation or attenuation of activity did not always correlate to the VTA neuronal response, and the age group with significantly higher behavioral responses did not always correlate to the age group with significantly higher VTA neuronal responses for a given MPD dose. These findings differ from similar studies recorded from the prefrontal cortex (PFC), which exhibited behavioral responses continuously directly correlated to PFC responses for increasing MPD doses. This demonstrates that unlike other areas of the brain, there is not a direct relationship between VTA firing and behavioral activity, suggesting that there is input or modulation of this area from elsewhere in the brain. Further investigation is needed to clearly understand the relationship between VTA firing rates and behavioral responses to different MPD doses, especially given the significant differences in response between young and adult animals and the increasing use of the drug in adolescent populations.
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Chamakalayil S, Strasser J, Vogel M, Brand S, Walter M, Dürsteler KM. Methylphenidate for Attention-Deficit and Hyperactivity Disorder in Adult Patients With Substance Use Disorders: Good Clinical Practice. Front Psychiatry 2020; 11:540837. [PMID: 33574770 PMCID: PMC7870681 DOI: 10.3389/fpsyt.2020.540837] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 12/16/2020] [Indexed: 11/16/2022] Open
Abstract
Attention-deficit and hyperactivity disorder (ADHD) is a widespread neurodevelopmental disorder in children and adolescents, persisting into adulthood in a majority of them. ADHD and substance use disorders (SUDs) commonly co-occur in the clinical adult population. The higher-than-normal prevalence rates of SUDs in people with ADHD indicate increased risk for developing SUD. This narrative review deals with the question of whether or not adults with both disorders should be treated with methylphenidate (MPH), addressing specific issues surrounding this form of treatment. MPH is considered as first-line pharmacotherapy for ADHD. However, because of its stimulant-like reinforcing properties, MPH has a significant addictive potential to which persons with SUDs are especially susceptible. Appropriate treatment is therefore complex. Because of concerns about misuse and diversion of MPH medication, clinicians may be reluctant to use MPH to manage ADHD symptoms in these patients. However, it is essential to diagnose and treat ADHD adequately as appropriate therapy reduces the impairments, as well as the risk of developing comorbid disorders and poor treatment response. MPH should not be deprived of these patients because of the risk for misuse, especially as several strategies can be applied to minimize this risk. To conclude, carefully applied guideline-based diagnostics to clarify the potential presence of ADHD as well as a responsible prescription practice in a well-defined therapeutic setting with reliable monitoring of medication intake and regular consultations are essential conditions for a safe and proficient MPH treatment of ADHD in patients with SUD.
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Affiliation(s)
- Sunsha Chamakalayil
- Department of Addictive Disorders, Psychiatric University Clinic Basel, Basel, Switzerland
| | - Johannes Strasser
- Department of Addictive Disorders, Psychiatric University Clinic Basel, Basel, Switzerland
| | - Marc Vogel
- Department of Addictive Disorders, Psychiatric University Clinic Basel, Basel, Switzerland.,Department of Addictive Disorders, Psychiatric Services Thurgau, Münsterlingen, Switzerland
| | - Serge Brand
- Center for Affective, Stress and Sleep Disorders (ZASS), Psychiatric University Hospital Basel, Basel, Switzerland.,Department of Clinical Research, University of Basel, Basel, Switzerland.,Division of Sport and Psychosocial Health, Department of Sport, Exercise, and Health, University of Basel, Basel, Switzerland.,Substance Abuse Prevention Research Center and Sleep Disorders Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran.,School of Medicine, Tehran University of Medical Sciences (TUMS), Tehrren, Iran
| | - Marc Walter
- Department of Addictive Disorders, Psychiatric University Clinic Basel, Basel, Switzerland
| | - Kenneth M Dürsteler
- Department of Addictive Disorders, Psychiatric University Clinic Basel, Basel, Switzerland.,Department for Psychiatry, Psychotherapy and Psychosomatic, Psychiatric Hospital, University of Zurich, Zurich, Switzerland
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