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Ecevitoglu A, Meka N, Rotolo RA, Edelstein GA, Srinath S, Beard KR, Carratala-Ros C, Presby RE, Cao J, Okorom A, Newman AH, Correa M, Salamone JD. Potential therapeutics for effort-related motivational dysfunction: assessing novel atypical dopamine transport inhibitors. Neuropsychopharmacology 2024; 49:1309-1317. [PMID: 38429498 PMCID: PMC11224370 DOI: 10.1038/s41386-024-01826-1] [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: 12/02/2023] [Revised: 01/28/2024] [Accepted: 02/05/2024] [Indexed: 03/03/2024]
Abstract
People with depression and other neuropsychiatric disorders can experience motivational dysfunctions such as fatigue and anergia, which involve reduced exertion of effort in goal-directed activity. To model effort-related motivational dysfunction, effort-based choice tasks can be used, in which rats can select between obtaining a preferred reinforcer by high exertion of effort vs. a low effort/less preferred option. Preclinical data indicate that dopamine transport (DAT) inhibitors can reverse pharmacologically-induced low-effort biases and increase selection of high-effort options in effort-based choice tasks. Although classical DAT blockers like cocaine can produce undesirable effects such as liability for misuse and psychotic reactions, not all DAT inhibitors have the same neurochemical profile. The current study characterized the effort-related effects of novel DAT inhibitors that are modafinil analogs and have a range of binding profiles and neurochemical actions (JJC8-088, JJC8-089, RDS3-094, and JJC8-091) by using two different effort-related choice behavior tasks in male Sprague-Dawley rats. JJC8-088, JJC8-089, and RDS3-094 significantly reversed the low-effort bias induced by the VMAT-2 inhibitor tetrabenazine, increasing selection of high-effort fixed ratio 5 lever pressing vs. chow intake. In addition, JJC8-089 reversed the effects of tetrabenazine in female rats. JJC8-088 and JJC8-089 also increased selection of high-effort progressive ratio responding in a choice task. However, JJC8-091 failed to produce these outcomes, potentially due to its unique pharmacological profile (i.e., binding to an occluded conformation of DAT). Assessment of a broad range of DAT inhibitors with different neurochemical characteristics may lead to the identification of compounds that are useful for treating motivational dysfunction in humans.
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Affiliation(s)
- Alev Ecevitoglu
- Psychological Sciences, University of Connecticut, Storrs, CT, 06269-1020, USA
| | - Nicolette Meka
- Psychological Sciences, University of Connecticut, Storrs, CT, 06269-1020, USA
| | - Renee A Rotolo
- Psychological Sciences, University of Connecticut, Storrs, CT, 06269-1020, USA
| | - Gayle A Edelstein
- Psychological Sciences, University of Connecticut, Storrs, CT, 06269-1020, USA
| | - Sonya Srinath
- Psychological Sciences, University of Connecticut, Storrs, CT, 06269-1020, USA
| | - Kathryn R Beard
- Psychological Sciences, University of Connecticut, Storrs, CT, 06269-1020, USA
| | - Carla Carratala-Ros
- Psychological Sciences, University of Connecticut, Storrs, CT, 06269-1020, USA
- Area de Psicobiología. Universitat Jaume I, Castelló, Spain
| | - Rose E Presby
- Psychological Sciences, University of Connecticut, Storrs, CT, 06269-1020, USA
| | - Jianjing Cao
- Medicinal Chemistry Section, NIDA-Intramural Research Program, Baltimore, MD, 21224, USA
| | - Amarachi Okorom
- Medicinal Chemistry Section, NIDA-Intramural Research Program, Baltimore, MD, 21224, USA
| | - Amy H Newman
- Medicinal Chemistry Section, NIDA-Intramural Research Program, Baltimore, MD, 21224, USA
| | - Mercè Correa
- Area de Psicobiología. Universitat Jaume I, Castelló, Spain
| | - John D Salamone
- Psychological Sciences, University of Connecticut, Storrs, CT, 06269-1020, USA.
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Hersey M, Mereu M, Jones CS, Bartole MK, Chen AY, Cao J, Hiranita T, Chun LE, Lopez JP, Katz JL, Newman AH, Tanda G. Dual DAT and sigma receptor inhibitors attenuate cocaine effects on nucleus accumbens dopamine dynamics in rats. Eur J Neurosci 2024; 59:2436-2449. [PMID: 38444104 PMCID: PMC11108740 DOI: 10.1111/ejn.16293] [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: 09/08/2023] [Revised: 01/10/2024] [Accepted: 02/07/2024] [Indexed: 03/07/2024]
Abstract
Psychostimulant use disorders (PSUD) are prevalent; however, no FDA-approved medications have been made available for treatment. Previous studies have shown that dual inhibitors of the dopamine transporter (DAT) and sigma receptors significantly reduce the behavioral/reinforcing effects of cocaine, which have been associated with stimulation of extracellular dopamine (DA) levels resulting from DAT inhibition. Here, we employ microdialysis and fast scan cyclic voltammetry (FSCV) procedures to investigate the effects of dual inhibitors of DAT and sigma receptors in combination with cocaine on nucleus accumbens shell (NAS) DA dynamics in naïve male Sprague Dawley rats. In microdialysis studies, administration of rimcazole (3, 10 mg/kg; i.p.) or its structural analog SH 3-24 (1, 3 mg/kg; i.p.), compounds that are dual inhibitors of DAT and sigma receptors, significantly reduced NAS DA efflux stimulated by increasing doses of cocaine (0.1, 0.3, 1.0 mg/kg; i.v.). Using the same experimental conditions, in FSCV tests, we show that rimcazole pretreatments attenuated cocaine-induced stimulation of evoked NAS DA release but produced no additional effect on DA clearance rate. Under the same conditions, JJC8-091, a modafinil analog and dual inhibitor of DAT and sigma receptors, similarly attenuated cocaine-induced stimulation of evoked NAS DA release but produced no additional effect on DA clearance rate. Our results provide the neurochemical groundwork towards understanding actions of dual inhibitors of DAT and sigma receptors on DA dynamics that likely mediate the behavioral effects of psychostimulants like cocaine.
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Affiliation(s)
- Melinda Hersey
- Medication Development Program, NIDA IRP, Baltimore, MD 21224, USA
| | - Maddalena Mereu
- Medication Development Program, NIDA IRP, Baltimore, MD 21224, USA
| | - Claire S. Jones
- Medication Development Program, NIDA IRP, Baltimore, MD 21224, USA
| | | | - Andy Y. Chen
- Medication Development Program, NIDA IRP, Baltimore, MD 21224, USA
| | - Jianjing Cao
- Medicinal Chemistry Section, NIDA IRP, Baltimore, MD 21224, USA
| | | | - Lauren E. Chun
- Medication Development Program, NIDA IRP, Baltimore, MD 21224, USA
| | - Jessica P. Lopez
- Medication Development Program, NIDA IRP, Baltimore, MD 21224, USA
| | | | - Amy Hauck Newman
- Medication Development Program, NIDA IRP, Baltimore, MD 21224, USA
- Medicinal Chemistry Section, NIDA IRP, Baltimore, MD 21224, USA
| | - Gianluigi Tanda
- Medication Development Program, NIDA IRP, Baltimore, MD 21224, USA
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Hersey M, Tanda G. Modafinil, an atypical CNS stimulant? ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2023; 99:287-326. [PMID: 38467484 DOI: 10.1016/bs.apha.2023.10.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/13/2024]
Abstract
Modafinil is a central nervous system stimulant approved for the treatment of narcolepsy and sleep disorders. Due to its wide range of biochemical actions, modafinil has been explored for other potential therapeutic uses. Indeed, it has shown promise as a therapy for cognitive disfunction resulting from neurologic disorders like ADHD, and as a smart drug in non-medical settings. The mechanism(s) of actions underlying the therapeutic efficacy of this agent remains largely elusive. Modafinil is known to inhibit the dopamine transporter, thus decreasing dopamine reuptake following neuronal release, an effect shared by addictive psychostimulants. However, modafinil is unique in that only a few cases of dependence on this drug have been reported, as compared to other psychostimulants. Moreover, modafinil has been tested, with some success, as a potential therapeutic agent to combat psychostimulant and other substance use disorders. Modafinil has additional, but less understood, actions on other neurotransmitter systems (GABA, glutamate, serotonin, norepinephrine, etc.). These interactions, together with its ability to activate selected brain regions, are likely one of the keys to understand its unique pharmacology and therapeutic activity as a CNS stimulant. In this chapter, we outline the pharmacokinetics and pharmacodynamics of modafinil that suggest it has an "atypical" CNS stimulant profile. We also highlight the current approved and off label uses of modafinil, including its beneficial effects as a treatment for sleep disorders, cognitive functions, and substance use disorders.
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Affiliation(s)
- Melinda Hersey
- Medication Development Program, NIDA-IRP, NIH, Baltimore, MD, United States
| | - Gianluigi Tanda
- Medication Development Program, NIDA-IRP, NIH, Baltimore, MD, United States.
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Yepez JE, Juárez J. Atomoxetine promotes incentive value of modafinil and sensitizes exploratory behavior. Pharmacol Biochem Behav 2023; 230:173618. [PMID: 37595803 DOI: 10.1016/j.pbb.2023.173618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 08/14/2023] [Accepted: 08/15/2023] [Indexed: 08/20/2023]
Abstract
Substance dependence is a disorder that alters the functioning of the nervous system due to frequent abuse of drugs. The role of dopamine in the addictive effect of psychostimulants is well known; however, the involvement of the noradrenergic system is still unclear and poorly understood, though drugs like cocaine and amphetamines are known to exert significant activity on this system. The drug modafinil (MOD) has no proven addictive effect. It promotes wakefulness by acting mainly on the dopaminergic system and, to a lesser degree, the noradrenergic (NOR) system. Atomoxetine (ATX) is a non-stimulant drug that acts only on the NOR system, enhancing its activity. The aims of the present study were to analyze the effect of co-activating the DA and NOR systems (with MOD and ATX, respectively) on motor activity and exploratory behavior, and to examine the possible emergence of rewarding properties of MOD and an MOD+ATX mixture. Male Wistar rats at postnatal day 60 were treated chronically (16 days) with either monotherapy with 2ATX, 4ATX, or 60MOD mg/kg, two combinations of these substances -60MOD + 2ATX and 60MOD + 4ATX- or a vehicle. The rats co-administered with 60MOD + 4ATX reduced the rearing behavior frequency induced by MOD, but this behavior was sensitized by self-administration of the MOD+ATX mixture after chronic treatment. The rats pre-treated with 60MOD + 4ATX showed higher self-administration of MOD and greater activity on an operant task to obtain the MOD+ATX mixture. In addition, the 60MOD, 2ATX, and 60MOD + 2ATX groups showed sensitization of exploratory behavior after ingesting the mixture. Results suggest that the noradrenergic system enhances the incentive value of MOD and a MOD+ATX mixture, while also playing an important role in the sensitization of exploratory behavior.
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Affiliation(s)
- Jesús E Yepez
- Laboratorio de Farmacología y Conducta, Instituto de Neurociencias, CUCBA, Universidad de Guadalajara, Guadalajara, Jalisco, Mexico
| | - Jorge Juárez
- Laboratorio de Farmacología y Conducta, Instituto de Neurociencias, CUCBA, Universidad de Guadalajara, Guadalajara, Jalisco, Mexico.
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Hersey M, Bartole MK, Jones CS, Newman AH, Tanda G. Are There Prevalent Sex Differences in Psychostimulant Use Disorder? A Focus on the Potential Therapeutic Efficacy of Atypical Dopamine Uptake Inhibitors. Molecules 2023; 28:5270. [PMID: 37446929 DOI: 10.3390/molecules28135270] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 06/23/2023] [Accepted: 06/26/2023] [Indexed: 07/15/2023] Open
Abstract
Psychostimulant use disorders (PSUD) affect a growing number of men and women and exert sizable public health and economic burdens on our global society. Notably, there are some sex differences in the onset of dependence, relapse rates, and treatment success with PSUD observed in preclinical and clinical studies. The subtle sex differences observed in the behavioral aspects of PSUD may be associated with differences in the neurochemistry of the dopaminergic system between sexes. Preclinically, psychostimulants have been shown to increase synaptic dopamine (DA) levels and may downregulate the dopamine transporter (DAT). This effect is greatest in females during the high estradiol phase of the estrous cycle. Interestingly, women have been shown to be more likely to begin drug use at younger ages and report higher levels of desire to use cocaine than males. Even though there is currently no FDA-approved medication, modafinil, a DAT inhibitor approved for use in the treatment of narcolepsy and sleep disorders, has shown promise in the treatment of PSUD among specific populations of affected individuals. In this review, we highlight the therapeutic potential of modafinil and other atypical DAT inhibitors focusing on the lack of sex differences in the actions of these agents.
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Affiliation(s)
- Melinda Hersey
- Medication Development Program, NIDA IRP, Baltimore, MD 21224, USA
| | | | - Claire S Jones
- Medication Development Program, NIDA IRP, Baltimore, MD 21224, USA
| | - Amy Hauck Newman
- Medication Development Program, NIDA IRP, Baltimore, MD 21224, USA
| | - Gianluigi Tanda
- Medication Development Program, NIDA IRP, Baltimore, MD 21224, USA
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Rahimi O, Cao J, Lam J, Childers SR, Rais R, Porrino LJ, Newman AH, Nader MA. The Effects of the Dopamine Transporter Ligands JJC8-088 and JJC8-091 on Cocaine versus Food Choice in Rhesus Monkeys. J Pharmacol Exp Ther 2023; 384:372-381. [PMID: 36507847 PMCID: PMC9976790 DOI: 10.1124/jpet.122.001363] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 11/26/2022] [Accepted: 11/30/2022] [Indexed: 12/12/2022] Open
Abstract
Although there are no Food and Drug Administration-approved treatments for cocaine use disorder, several modafinil analogs have demonstrated promise in reducing cocaine self-administration and reinstatement in rats. Furthermore, the range of dopamine transporter (DAT) compounds provides an opportunity to develop pharmacotherapeutics without abuse liability. This study extended the comparison of JJC8-088 and JJC8-091, the former compound having higher DAT affinity and predicted abuse liability, to rhesus monkeys using a concurrent cocaine versus food schedule of reinforcement. First, binding to striatal DAT was examined in cocaine-naïve monkey tissue. Next, intravenous pharmacokinetics of both JJC compounds were evaluated in cocaine-experienced male monkeys (n = 3/drug). In behavioral studies, acute and chronic administration of both compounds were evaluated in these same monkeys responding under a concurrent food versus cocaine (0 and 0.003-0.1 mg/kg per injection) schedule of reinforcement. In nonhuman primate striatum, JJC8-088 had higher DAT affinity compared with JJC8-091 (14.4 ± 9 versus 2730 ± 1270 nM, respectively). Both JJC compounds had favorable plasma pharmacokinetics for behavioral assessments, with half-lives of 1.1 hours and 3.5 hours for JJC8-088 (0.7 mg/kg, i.v.) and JJC8-091 (1.9 mg/kg, i.v.), respectively. Acute treatment with both compounds shifted the cocaine dose-response curve to the left. Chronic treatment with JJC8-088 decreased cocaine choice in two of the three monkeys, whereas JJC8-091 only modestly reduced cocaine allocation in one monkey. Differences in affinities of JJC8-091 DAT binding in monkeys compared with rats may account for the poor rodent-to-monkey translation. Future studies should evaluate atypical DAT blockers in combination with behavioral interventions that may further decrease cocaine choice. SIGNIFICANCE STATEMENT: Cocaine use disorder (CUD) remains a significant public health problem with no Food and Drug Administration-approved treatments. The ability of drugs that act in the brain in a similar manner to cocaine, but with lower abuse liability, has clinical implications for a treatment of CUD.
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Affiliation(s)
- Omeed Rahimi
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, North Carolina (O.R., S.R.C., L.J.P., M.A.N.); Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland (J.C., J.L., A.H.N.); Department of Neurology, Johns Hopkins Drug Discovery, The Johns Hopkins University School of Medicine, Baltimore, Maryland (J.L., R.R.); and EncepHeal Therapeutics, Inc., Winston-Salem, North Carolina (O.R., S.R.C.)
| | - Jianjing Cao
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, North Carolina (O.R., S.R.C., L.J.P., M.A.N.); Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland (J.C., J.L., A.H.N.); Department of Neurology, Johns Hopkins Drug Discovery, The Johns Hopkins University School of Medicine, Baltimore, Maryland (J.L., R.R.); and EncepHeal Therapeutics, Inc., Winston-Salem, North Carolina (O.R., S.R.C.)
| | - Jenny Lam
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, North Carolina (O.R., S.R.C., L.J.P., M.A.N.); Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland (J.C., J.L., A.H.N.); Department of Neurology, Johns Hopkins Drug Discovery, The Johns Hopkins University School of Medicine, Baltimore, Maryland (J.L., R.R.); and EncepHeal Therapeutics, Inc., Winston-Salem, North Carolina (O.R., S.R.C.)
| | - Steven R Childers
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, North Carolina (O.R., S.R.C., L.J.P., M.A.N.); Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland (J.C., J.L., A.H.N.); Department of Neurology, Johns Hopkins Drug Discovery, The Johns Hopkins University School of Medicine, Baltimore, Maryland (J.L., R.R.); and EncepHeal Therapeutics, Inc., Winston-Salem, North Carolina (O.R., S.R.C.)
| | - Rana Rais
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, North Carolina (O.R., S.R.C., L.J.P., M.A.N.); Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland (J.C., J.L., A.H.N.); Department of Neurology, Johns Hopkins Drug Discovery, The Johns Hopkins University School of Medicine, Baltimore, Maryland (J.L., R.R.); and EncepHeal Therapeutics, Inc., Winston-Salem, North Carolina (O.R., S.R.C.)
| | - Linda J Porrino
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, North Carolina (O.R., S.R.C., L.J.P., M.A.N.); Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland (J.C., J.L., A.H.N.); Department of Neurology, Johns Hopkins Drug Discovery, The Johns Hopkins University School of Medicine, Baltimore, Maryland (J.L., R.R.); and EncepHeal Therapeutics, Inc., Winston-Salem, North Carolina (O.R., S.R.C.)
| | - Amy Hauck Newman
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, North Carolina (O.R., S.R.C., L.J.P., M.A.N.); Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland (J.C., J.L., A.H.N.); Department of Neurology, Johns Hopkins Drug Discovery, The Johns Hopkins University School of Medicine, Baltimore, Maryland (J.L., R.R.); and EncepHeal Therapeutics, Inc., Winston-Salem, North Carolina (O.R., S.R.C.)
| | - Michael A Nader
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, North Carolina (O.R., S.R.C., L.J.P., M.A.N.); Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland (J.C., J.L., A.H.N.); Department of Neurology, Johns Hopkins Drug Discovery, The Johns Hopkins University School of Medicine, Baltimore, Maryland (J.L., R.R.); and EncepHeal Therapeutics, Inc., Winston-Salem, North Carolina (O.R., S.R.C.)
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Zlomuzica A, Plank L, Dere E. A new path to mental disorders: Through gap junction channels and hemichannels. Neurosci Biobehav Rev 2022; 142:104877. [PMID: 36116574 DOI: 10.1016/j.neubiorev.2022.104877] [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: 01/31/2022] [Revised: 08/20/2022] [Accepted: 09/13/2022] [Indexed: 11/18/2022]
Abstract
Behavioral disturbances related to emotional regulation, reward processing, cognition, sleep-wake regulation and activity/movement represent core symptoms of most common mental disorders. Increasing empirical and theoretical evidence suggests that normal functioning of these behavioral domains relies on fine graded coordination of neural and glial networks which are maintained and modulated by intercellular gap junction channels and unapposed pannexin or connexin hemichannels. Dysfunctions in these networks might contribute to the development and maintenance of psychopathological and neurobiological features associated with mental disorders. Here we review and discuss the evidence indicating a prominent role of gap junction channel and hemichannel dysfunction in core symptoms of mental disorders. We further discuss how the increasing knowledge on intercellular gap junction channels and unapposed pannexin or connexin hemichannels in the brain might lead to deeper mechanistic insight in common mental disorders and to the development of novel treatment approaches. We further attempt to exemplify what type of future research on this topic could be integrated into multidimensional approaches to understand and cure mental disorders.
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Affiliation(s)
- Armin Zlomuzica
- Department of Behavioral and Clinical Neuroscience, Ruhr-University Bochum (RUB), Massenbergstraße 9-13, D-44787 Bochum, Germany.
| | - Laurin Plank
- Department of Behavioral and Clinical Neuroscience, Ruhr-University Bochum (RUB), Massenbergstraße 9-13, D-44787 Bochum, Germany
| | - Ekrem Dere
- Department of Behavioral and Clinical Neuroscience, Ruhr-University Bochum (RUB), Massenbergstraße 9-13, D-44787 Bochum, Germany; Sorbonne Université. Institut de Biologie Paris-Seine, (IBPS), Département UMR 8256: Adaptation Biologique et Vieillissement, UFR des Sciences de la Vie, Campus Pierre et Marie Curie, Bâtiment B, 9 quai Saint Bernard, F-75005 Paris, France.
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Liu X, Vickstrom CR, Yu H, Liu S, Snarrenberg ST, Friedman V, Mu L, Chen B, Kelly TJ, Baker DA, Liu QS. Epac2 in midbrain dopamine neurons contributes to cocaine reinforcement via facilitation of dopamine release. eLife 2022; 11:80747. [PMID: 35993549 PMCID: PMC9436413 DOI: 10.7554/elife.80747] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 08/21/2022] [Indexed: 11/21/2022] Open
Abstract
Repeated exposure to drugs of abuse results in an upregulation of cAMP signaling in the mesolimbic dopamine system, a molecular adaptation thought to be critically involved in the development of drug dependence. Exchange protein directly activated by cAMP (Epac2) is a major cAMP effector abundantly expressed in the brain. However, it remains unknown whether Epac2 contributes to cocaine reinforcement. Here, we report that Epac2 in the mesolimbic dopamine system promotes cocaine reinforcement via enhancement of dopamine release. Conditional knockout of Epac2 from midbrain dopamine neurons (Epac2-cKO) and the selective Epac2 inhibitor ESI-05 decreased cocaine self-administration in mice under both fixed-ratio and progressive-ratio reinforcement schedules and across a broad range of cocaine doses. In addition, Epac2-cKO led to reduced evoked dopamine release, whereas Epac2 agonism robustly enhanced dopamine release in the nucleus accumbens in vitro. This mechanism is central to the behavioral effects of Epac2 disruption, as chemogenetic stimulation of ventral tegmental area (VTA) dopamine neurons via deschloroclozapine (DCZ)-induced activation of Gs-DREADD increased dopamine release and reversed the impairment of cocaine self-administration in Epac2-cKO mice. Conversely, chemogenetic inhibition of VTA dopamine neurons with Gi-DREADD reduced dopamine release and cocaine self-administration in wild-type mice. Epac2-mediated enhancement of dopamine release may therefore represent a novel and powerful mechanism that contributes to cocaine reinforcement.
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Affiliation(s)
- Xiaojie Liu
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, United States
| | - Casey R Vickstrom
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, United States
| | - Hao Yu
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, United States
| | - Shuai Liu
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, United States
| | - Shana Terai Snarrenberg
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, United States
| | - Vladislav Friedman
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, United States
| | - Lianwei Mu
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, United States
| | - Bixuan Chen
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, United States
| | - Thomas J Kelly
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, United States
| | - David A Baker
- Department of Biomedical Sciences, Marquette University, Milwaukee, United States
| | - Qing-Song Liu
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, United States
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9
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Van Puyvelde M, Rietjens G, Helmhout P, Mairesse O, Van Cutsem J, Pattyn N. The submariners' sleep study. A field investigation of sleep and circadian hormones during a 67-days submarine mission with a strict 6h-on/6h-off watch routine. J Appl Physiol (1985) 2022; 132:1069-1079. [PMID: 35142558 DOI: 10.1152/japplphysiol.00130.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The submarine working and living environment is an isolated, confined, and extreme (ICE) environment where a continuous on-watch is required to fulfill the tactical objectives. The current study examined whether a physiological and behavioral adjustment to an operational watch standing scheme occurred in terms of hormonal secretion (i.e., melatonin and cortisol) and sleep during a 67-days undersea mission. The crew followed a strict scheme of watch-on blocks at 0:00-06:00 h and at 12:00-18:00 h (group 1, diurnal sleep group) or watch-on blocks at 06:00-12:00 h and 18:00-24:00 h (group 2, nocturnal sleep group). We sampled saliva during the operational blocks over a 24h period at day 55 of the mission and collected sleep actigraphy data during the entire mission in 10 participants. Sleep showed a biphasic split pattern with significantly unequal distributions of total sleep time (TST) and sleep efficiency (SE) between the two sleeping blocks, i.e., one long and one short sleep bout. Melatonin secretion showed no adjustment at the end of the mission to the watch standing blocks, following an endogenous circadian rhythm independent from the social zeitgebers with indications of a phase shift. Cortisol secretion however matched the biphasic work-sleep shift routine. Human physiology does not fully obey operational needs and there are differences in adjustment between melatonin and cortisol. A watch standing schedule that provides a balance between physiology and operationality still needs to be established. The potential adaptation effects of bright light therapy and melatonin supplementation should be investigated in future research.
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Affiliation(s)
- Martine Van Puyvelde
- VIPER Research Unit, LIFE department, Royal Military Academy, Brussels, Belgium.,Brain, Body and Cognition, Department of Psychology, Faculty of Psychology and Educational Sciences, Vrije Universiteit Brussel, Brussels, Belgium.,Clinical and Lifespan Psychology, Department of Psychology and Educational Sciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Gerard Rietjens
- MFYS-BLITS, Human Physiology Department, Vrije Universiteit Brussel, Brussels, Belgium.,Training Medicine and Training Physiology, Army Command, Directory of Personnel, Royal Netherlands Army, Utrecht, The Netherlands
| | - Pieter Helmhout
- Training Medicine and Training Physiology, Army Command, Directory of Personnel, Royal Netherlands Army, Utrecht, The Netherlands
| | - Olivier Mairesse
- VIPER Research Unit, LIFE department, Royal Military Academy, Brussels, Belgium.,Brain, Body and Cognition, Department of Psychology, Faculty of Psychology and Educational Sciences, Vrije Universiteit Brussel, Brussels, Belgium.,Sleep Laboratory and Unit for Clinical Chronobiology, CHU Brugmann, Brussels, Belgium
| | - Jeroen Van Cutsem
- VIPER Research Unit, LIFE department, Royal Military Academy, Brussels, Belgium.,MFYS-BLITS, Human Physiology Department, Vrije Universiteit Brussel, Brussels, Belgium
| | - Nathalie Pattyn
- VIPER Research Unit, LIFE department, Royal Military Academy, Brussels, Belgium.,MFYS-BLITS, Human Physiology Department, Vrije Universiteit Brussel, Brussels, Belgium
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10
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Van Puyvelde M, Van Cutsem J, Lacroix E, Pattyn N. A State-of-the-Art Review on the Use of Modafinil as A Performance-enhancing Drug in the Context of Military Operationality. Mil Med 2021; 187:52-64. [PMID: 34632515 DOI: 10.1093/milmed/usab398] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 09/09/2021] [Accepted: 09/20/2021] [Indexed: 11/14/2022] Open
Abstract
INTRODUCTION Modafinil is an eugeroic drug that has been examined to maintain or recover wakefulness, alertness, and cognitive performance when sleep deprived. In a nonmilitary context, the use of modafinil as a nootropic or smart drug, i.e., to improve cognitive performance without being sleep deprived, increases. Although cognitive performance is receiving more explicit attention in a military context, research into the impact of modafinil as a smart drug in function of operationality is lacking. Therefore, the current review aimed at presenting a current state-of-the-art and research agenda on modafinil as a smart drug. Beside the question whether modafinil has an effect or not on cognitive performance, we examined four research questions based on the knowledge on modafinil in sleep-deprived subjects: (1) Is there a difference between the effect of modafinil as a smart drug when administered in repeated doses versus one single dose?; (2) Is the effect of modafinil as a smart drug dose-dependent?; (3) Are there individual-related and/or task-related impact factors?; and (4) What are the reported mental and/or somatic side effects of modafinil as a smart drug? METHOD We conducted a systematic search of the literature in the databases PubMed, Web of Science, and Scopus, using the search terms "Modafinil" and "Cognitive enhance*" in combination with specific terms related to the research questions. The inclusion criteria were studies on healthy human subjects with quantifiable cognitive outcome based on cognitive tasks. RESULTS We found no literature on the impact of a repeated intake of modafinil as a smart drug, although, in users, intake occurs on a regular basis. Moreover, although modafinil was initially said to comprise no risk for abuse, there are now indications that modafinil works on the same neurobiological mechanisms as other addictive stimulants. There is also no thorough research into a potential risk for overconfidence, whereas this risk was identified in sleep-deprived subjects. Furthermore, eventual enhancing effects were beneficial only in persons with an initial lower performance level and/or performing more difficult tasks and modafinil has an adverse effect when used under time pressure and may negatively impact physical performance. Finally, time-on-task may interact with the dose taken. DISCUSSION The use of modafinil as a smart drug should be examined in function of different military profiles considering their individual performance level and the task characteristics in terms of cognitive demands, physical demands, and sleep availability. It is not yet clear to what extent an improvement in one component (e.g., cognitive performance) may negatively affect another component (e.g., physical performance). Moreover, potential risks for abuse and overconfidence in both regular and occasional intake should be thoroughly investigated to depict the trade-off between user benefits and unwanted side effects. We identified that there is a current risk to the field, as this trade-off has been deemed acceptable for sleep-deprived subjects (considering the risk of sleep deprivation to performance) but this reasoning cannot and should not be readily transposed to non-sleep-deprived individuals. We thus conclude against the use of modafinil as a cognitive enhancer in military contexts that do not involve sleep deprivation.
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Affiliation(s)
- Martine Van Puyvelde
- VIPER Research Unit, Department of LIFE, Royal Military Academy, Brussels 1000, Belgium.,Brain, Body and Cognition, Department of Psychology, Vrije Universiteit Brussel, Brussels 1050, Belgium.,Clinical & Lifespan Psychology, Department of Psychology and Educational Sciences, Vrije Universiteit Brussel, Brussels 1050, Belgium
| | - Jeroen Van Cutsem
- VIPER Research Unit, Department of LIFE, Royal Military Academy, Brussels 1000, Belgium.,MFYS-BLITS, Department of Human Physiology, Vrije Universiteit Brussel, Brussels 1050, Belgium
| | - Emilie Lacroix
- VIPER Research Unit, Department of LIFE, Royal Military Academy, Brussels 1000, Belgium
| | - Nathalie Pattyn
- VIPER Research Unit, Department of LIFE, Royal Military Academy, Brussels 1000, Belgium.,MFYS-BLITS, Department of Human Physiology, Vrije Universiteit Brussel, Brussels 1050, Belgium
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11
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Hersey M, Bacon AK, Bailey LG, Coggiano MA, Newman AH, Leggio L, Tanda G. Psychostimulant Use Disorder, an Unmet Therapeutic Goal: Can Modafinil Narrow the Gap? Front Neurosci 2021; 15:656475. [PMID: 34121988 PMCID: PMC8187604 DOI: 10.3389/fnins.2021.656475] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 04/20/2021] [Indexed: 12/11/2022] Open
Abstract
The number of individuals affected by psychostimulant use disorder (PSUD) has increased rapidly over the last few decades resulting in economic, emotional, and physical burdens on our society. Further compounding this issue is the current lack of clinically approved medications to treat this disorder. The dopamine transporter (DAT) is a common target of psychostimulant actions related to their use and dependence, and the recent availability of atypical DAT inhibitors as a potential therapeutic option has garnered popularity in this research field. Modafinil (MOD), which is approved for clinical use for the treatment of narcolepsy and sleep disorders, blocks DAT just like commonly abused psychostimulants. However, preclinical and clinical studies have shown that it lacks the addictive properties (in both behavioral and neurochemical studies) associated with other abused DAT inhibitors. Clinical availability of MOD has facilitated its off-label use for several psychiatric disorders related to alteration of brain dopamine (DA) systems, including PSUD. In this review, we highlight clinical and preclinical research on MOD and its R-enantiomer, R-MOD, as potential medications for PSUD. Given the complexity of PSUD, we have also reported the effects of MOD on psychostimulant-induced appearance of several symptoms that could intensify the severity of the disease (i.e., sleep disorders and impairment of cognitive functions), besides the potential therapeutic effects of MOD on PSUD.
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Affiliation(s)
- Melinda Hersey
- Medication Development Program, Molecular Targets and Medication Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, MD, United States
| | - Amanda K. Bacon
- Medication Development Program, Molecular Targets and Medication Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, MD, United States
| | - Lydia G. Bailey
- Medication Development Program, Molecular Targets and Medication Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, MD, United States
| | - Mark A. Coggiano
- Medication Development Program, Molecular Targets and Medication Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, MD, United States
| | - Amy H. Newman
- Medication Development Program, Molecular Targets and Medication Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, MD, United States
| | - Lorenzo Leggio
- Medication Development Program, Molecular Targets and Medication Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, MD, United States
- Clinical Psychoneuroendo- crinology and Neuropsychopharmacology Section, Translational Addiction Medicine Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, MD, United States
- National Institute on Alcohol Abuse and Alcoholism, Division of Intramural Clinical and Biological Research, National Institutes of Health, Bethesda, MD, United States
| | - Gianluigi Tanda
- Medication Development Program, Molecular Targets and Medication Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, MD, United States
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Tanda G, Hersey M, Hempel B, Xi ZX, Newman AH. Modafinil and its structural analogs as atypical dopamine uptake inhibitors and potential medications for psychostimulant use disorder. Curr Opin Pharmacol 2020; 56:13-21. [PMID: 32927246 DOI: 10.1016/j.coph.2020.07.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 07/17/2020] [Accepted: 07/20/2020] [Indexed: 12/20/2022]
Abstract
Pharmacotherapeutics for treatment of psychostimulant use disorder are still an unmet medical goal. Recently, off label use of modafinil (MOD), an approved medication for treatment of sleep disturbances, has been tested as a therapeutic for cocaine and methamphetamine use disorder. Positive results have been found in subjects dependent on psychostimulants without concurrent abuse of other substances. Novel structural analogs of MOD have been synthesized in the search for compounds with potentially broader therapeutic efficacy than the parent drug. In the present report we review their potential efficacy as treatments for psychostimulant abuse and dependence assessed in preclinical tests. Results from these preclinical proof of concept studies reveal that some modafinil analogs do not possess typical cocaine-like neurochemical and behavioral effects. Further, they might blunt the reinforcing effects of psychostimulants in animal models, suggesting their potential efficacy as pharmacotherapeutics for treatment of psychostimulant use disorders.
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Affiliation(s)
- Gianluigi Tanda
- Medication Development Program, Molecular Targets and Medication Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, NIH, DHHS, 333 Cassell Drive, Baltimore, MD, 21224, USA.
| | - Melinda Hersey
- Medication Development Program, Molecular Targets and Medication Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, NIH, DHHS, 333 Cassell Drive, Baltimore, MD, 21224, USA
| | - Briana Hempel
- Medication Development Program, Molecular Targets and Medication Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, NIH, DHHS, 333 Cassell Drive, Baltimore, MD, 21224, USA
| | - Zheng-Xiong Xi
- Medication Development Program, Molecular Targets and Medication Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, NIH, DHHS, 333 Cassell Drive, Baltimore, MD, 21224, USA
| | - Amy Hauck Newman
- Medication Development Program, Molecular Targets and Medication Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, NIH, DHHS, 333 Cassell Drive, Baltimore, MD, 21224, USA
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