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Wadsworth HA, Warnecke AMP, Barlow JC, Robinson JK, Steimle E, Ronström JW, Williams PE, Galbraith CJ, Baldridge J, Jakowec MW, Davies DL, Yorgason JT. Ivermectin increases striatal cholinergic activity to facilitate dopamine terminal function. Cell Biosci 2024; 14:50. [PMID: 38632622 PMCID: PMC11025261 DOI: 10.1186/s13578-024-01228-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Accepted: 04/01/2024] [Indexed: 04/19/2024] Open
Abstract
Ivermectin (IVM) is a commonly prescribed antiparasitic treatment with pharmacological effects on invertebrate glutamate ion channels resulting in paralysis and death of invertebrates. However, it can also act as a modulator of some vertebrate ion channels and has shown promise in facilitating L-DOPA treatment in preclinical models of Parkinson's disease. The pharmacological effects of IVM on dopamine terminal function were tested, focusing on the role of two of IVM's potential targets: purinergic P2X4 and nicotinic acetylcholine receptors. Ivermectin enhanced electrochemical detection of dorsal striatum dopamine release. Although striatal P2X4 receptors were observed, IVM effects on dopamine release were not blocked by P2X4 receptor inactivation. In contrast, IVM attenuated nicotine effects on dopamine release, and antagonizing nicotinic receptors prevented IVM effects on dopamine release. IVM also enhanced striatal cholinergic interneuron firing. L-DOPA enhances dopamine release by increasing vesicular content. L-DOPA and IVM co-application further enhanced release but resulted in a reduction in the ratio between high and low frequency stimulations, suggesting that IVM is enhancing release largely through changes in terminal excitability and not vesicular content. Thus, IVM is increasing striatal dopamine release through enhanced cholinergic activity on dopamine terminals.
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Affiliation(s)
- Hillary A Wadsworth
- Department of Cellular Biology and Physiology, and Neuroscience Program, Brigham Young University, 4005 LSB, Provo, UT, 84602, USA
| | - Alicia M P Warnecke
- Titus Family Department of Clinical Pharmacy, School of Pharmacy, University of Southern California, 1985 Zonal Avenue, Los Angeles, CA, 90089, USA
| | - Joshua C Barlow
- Department of Cellular Biology and Physiology, and Neuroscience Program, Brigham Young University, 4005 LSB, Provo, UT, 84602, USA
| | - J Kayden Robinson
- Department of Cellular Biology and Physiology, and Neuroscience Program, Brigham Young University, 4005 LSB, Provo, UT, 84602, USA
| | - Emma Steimle
- Department of Cellular Biology and Physiology, and Neuroscience Program, Brigham Young University, 4005 LSB, Provo, UT, 84602, USA
| | - Joakim W Ronström
- Department of Cellular Biology and Physiology, and Neuroscience Program, Brigham Young University, 4005 LSB, Provo, UT, 84602, USA
| | - Pacen E Williams
- Department of Cellular Biology and Physiology, and Neuroscience Program, Brigham Young University, 4005 LSB, Provo, UT, 84602, USA
| | - Christopher J Galbraith
- Department of Cellular Biology and Physiology, and Neuroscience Program, Brigham Young University, 4005 LSB, Provo, UT, 84602, USA
| | - Jared Baldridge
- Department of Cellular Biology and Physiology, and Neuroscience Program, Brigham Young University, 4005 LSB, Provo, UT, 84602, USA
| | - Michael W Jakowec
- Titus Family Department of Clinical Pharmacy, School of Pharmacy, University of Southern California, 1985 Zonal Avenue, Los Angeles, CA, 90089, USA
| | - Daryl L Davies
- Department of Neurology, Keck School of Medicine, University of Southern California, 1333 San Pablo Street, Los Angeles, CA, 90033, USA
| | - Jordan T Yorgason
- Department of Cellular Biology and Physiology, and Neuroscience Program, Brigham Young University, 4005 LSB, Provo, UT, 84602, USA.
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2
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Calancie OG, Parr AC, Brien DC, Huang J, Pitigoi IC, Coe BC, Booij L, Khalid-Khan S, Munoz DP. Motor synchronization and impulsivity in pediatric borderline personality disorder with and without attention-deficit hyperactivity disorder: an eye-tracking study of saccade, blink and pupil behavior. Front Neurosci 2023; 17:1179765. [PMID: 37425020 PMCID: PMC10323365 DOI: 10.3389/fnins.2023.1179765] [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: 03/04/2023] [Accepted: 05/30/2023] [Indexed: 07/11/2023] Open
Abstract
Shifting motor actions from reflexively reacting to an environmental stimulus to predicting it allows for smooth synchronization of behavior with the outside world. This shift relies on the identification of patterns within the stimulus - knowing when a stimulus is predictable and when it is not - and launching motor actions accordingly. Failure to identify predictable stimuli results in movement delays whereas failure to recognize unpredictable stimuli results in early movements with incomplete information that can result in errors. Here we used a metronome task, combined with video-based eye-tracking, to quantify temporal predictive learning and performance to regularly paced visual targets at 5 different interstimulus intervals (ISIs). We compared these results to the random task where the timing of the target was randomized at each target step. We completed these tasks in female pediatric psychiatry patients (age range: 11-18 years) with borderline personality disorder (BPD) symptoms, with (n = 22) and without (n = 23) a comorbid attention-deficit hyperactivity disorder (ADHD) diagnosis, against controls (n = 35). Compared to controls, BPD and ADHD/BPD cohorts showed no differences in their predictive saccade performance to metronome targets, however, when targets were random ADHD/BPD participants made significantly more anticipatory saccades (i.e., guesses of target arrival). The ADHD/BPD group also significantly increased their blink rate and pupil size when initiating movements to predictable versus unpredictable targets, likely a reflection of increased neural effort for motor synchronization. BPD and ADHD/BPD groups showed increased sympathetic tone evidenced by larger pupil sizes than controls. Together, these results support normal temporal motor prediction in BPD with and without ADHD, reduced response inhibition in BPD with comorbid ADHD, and increased pupil sizes in BPD patients. Further these results emphasize the importance of controlling for comorbid ADHD when querying BPD pathology.
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Affiliation(s)
- Olivia G. Calancie
- Queen’s Eye Movement Lab, Centre for Neuroscience Studies, Queen’s University, Kingston, ON, Canada
| | - Ashley C. Parr
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, United States
| | - Don C. Brien
- Queen’s Eye Movement Lab, Centre for Neuroscience Studies, Queen’s University, Kingston, ON, Canada
| | - Jeff Huang
- Queen’s Eye Movement Lab, Centre for Neuroscience Studies, Queen’s University, Kingston, ON, Canada
| | - Isabell C. Pitigoi
- Queen’s Eye Movement Lab, Centre for Neuroscience Studies, Queen’s University, Kingston, ON, Canada
| | - Brian C. Coe
- Queen’s Eye Movement Lab, Centre for Neuroscience Studies, Queen’s University, Kingston, ON, Canada
| | - Linda Booij
- Department of Psychiatry, McGill University, Montreal, QC, Canada
- Research Centre and Eating Disorders Continuum, Douglas Mental Health University Institute, Montreal, QC, Canada
| | - Sarosh Khalid-Khan
- Queen’s Eye Movement Lab, Centre for Neuroscience Studies, Queen’s University, Kingston, ON, Canada
- Divison of Child and Youth Psychiatry, Department of Psychiatry, School of Medicine, Queen’s University, Kingston, ON, Canada
| | - Douglas P. Munoz
- Queen’s Eye Movement Lab, Centre for Neuroscience Studies, Queen’s University, Kingston, ON, Canada
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3
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Pauly RC, Bhimani RV, Li JX, Blough BE, Landavazo A, Park J. Distinct Effects of Methamphetamine Isomers on Limbic Norepinephrine and Dopamine Transmission in the Rat Brain. ACS Chem Neurosci 2023. [PMID: 36976755 DOI: 10.1021/acschemneuro.2c00689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023] Open
Abstract
Methamphetamine (METH) is a psychostimulant that primarily exerts its effects on the catecholamine (dopamine (DA) and norepinephrine (NE)) systems, which are implicated in drug addiction. METH exists as two distinct enantiomers, dextrorotatory (d) and levorotatory (l). In contrast to d-METH, the major component of illicit METH used to induce states of euphoria and alertness, l-METH is available without prescription as a nasal decongestant and has been highlighted as a potential agonist replacement therapy to treat stimulant use disorder. However, little is known regarding l-METH's effects on central catecholamine transmission and behavior. In this study, we used fast-scan cyclic voltammetry to elucidate how METH isomers impact NE and DA transmission in two limbic structures, the ventral bed nucleus of the stria terminalis (vBNST) and nucleus accumbens (NAc), respectively, of anesthetized rats. In addition, the dose-dependent effects of METH isomers on locomotion were characterized. d-METH (0.5, 2.0, 5.0 mg/kg) enhanced both electrically evoked vBNST-NE and NAc-DA concentrations and locomotion. Alternatively, l-METH increased electrically evoked NE concentration with minimal effects on DA regulation (release and clearance) and locomotion at lower doses (0.5 and 2.0 mg/kg). Furthermore, a high dose (5.0 mg/kg) of d-METH but not l-METH elevated baseline NE and DA concentrations. These results suggest mechanistic differences between NE and DA regulation by the METH isomers. Moreover, l-METH's asymmetric regulation of NE relative to DA may have distinct implications in behaviors and addiction, which will set the neurochemical framework for future studies examining l-METH as a potential treatment for stimulant use disorders.
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Affiliation(s)
| | | | | | - Bruce E Blough
- Center for Drug Discovery, RTI International, Research Triangle Park, Durham, North Carolina 27709, United States
| | - Antonio Landavazo
- Center for Drug Discovery, RTI International, Research Triangle Park, Durham, North Carolina 27709, United States
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4
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Demiral ŞB, Manza P, Biesecker E, Wiers C, Shokri-Kojori E, McPherson K, Dennis E, Johnson A, Tomasi D, Wang GJ, Volkow ND. Striatal D1 and D2 receptor availability are selectively associated with eye-blink rates after methylphenidate treatment. Commun Biol 2022; 5:1015. [PMID: 36163254 PMCID: PMC9513088 DOI: 10.1038/s42003-022-03979-5] [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: 01/31/2022] [Accepted: 09/12/2022] [Indexed: 11/18/2022] Open
Abstract
Eye-blink rate has been proposed as a biomarker of the brain dopamine system, however, findings have not been consistent. This study assessed the relationship between blink rates, measured after oral placebo) (PL) and after a challenge with oral methylphenidate (MP; 60 mg) and striatal D1 receptor (D1R) (measured at baseline) and D2 receptor (D2R) availability (measured after PL and after MP) in healthy participants. PET measures of baseline D1R ([11C]NNC112) (BL-D1R) and D2R availability ([11C]raclopride) after PL (PL-D2R) and after MP (MP-D2R) were quantified in the striatum as non-displaceable binding potential. MP reduced the number of blinks and increased the time participants kept their eyes open. Correlations with dopamine receptors were only significant for the eye blink measures obtained after MP; being positive for BL-D1R in putamen and MP-D2R in caudate (PL-D2R were not significant). MP-induced changes in blink rates (PL minus MP) were negatively correlated with BL-D1R in caudate and putamen. Our findings suggest that eye blink measures obtained while stressing the dopamine system might provide a more sensitive behavioral biomarker of striatal D1R or D2R in healthy volunteers than that obtained at baseline or after placebo. PET imaging in human participants revealed that D1 and D2 dopamine receptor availability was associated with eye-blink rates following treatment with oral methylphenidate, but not a placebo.
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Affiliation(s)
- Şükrü B Demiral
- National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD, USA.
| | - Peter Manza
- National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD, USA
| | - Erin Biesecker
- National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD, USA
| | - Corinde Wiers
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA, USA
| | | | | | - Evan Dennis
- National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD, USA
| | - Allison Johnson
- National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD, USA
| | - Dardo Tomasi
- National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD, USA
| | - Gene-Jack Wang
- National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD, USA
| | - Nora D Volkow
- National Institute on Drug Abuse, Bethesda, MD, USA.
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5
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Servonnet A, Allain F, Gravel-Chouinard A, Hernandez G, Bourdeau Caporuscio C, Legrix M, Lévesque D, Rompré PP, Samaha AN. Dopaminergic mechanisms underlying the expression of antipsychotic-induced dopamine supersensitivity in rats. Neuropharmacology 2021; 197:108747. [PMID: 34364897 DOI: 10.1016/j.neuropharm.2021.108747] [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: 05/31/2021] [Revised: 07/23/2021] [Accepted: 08/03/2021] [Indexed: 10/20/2022]
Abstract
Antipsychotic treatment can produce a dopamine-supersensitive state, potentiating the response to dopamine receptor stimulation. In both schizophrenia patients and rats, this is linked to tolerance to ongoing antipsychotic treatment. In rodents, dopamine supersensitivity is often confirmed by an exaggerated psychomotor response to d-amphetamine after discontinuation of antipsychotic exposure. Here we examined in rats the dopaminergic mechanisms mediating this enhanced behavioural response, as this could uncover pathophysiological processes underlying the expression of antipsychotic-evoked dopamine supersensitivity. Rats received 0.5 mg/kg/day haloperidol via osmotic minipump for 2 weeks, before treatment was discontinued. After cessation of antipsychotic treatment, rats showed a supersensitive psychomotor response to the D2 agonist quinpirole, but not to the D1 partial agonist SKF38393 or the dopamine reuptake blocker GBR12783. Furthermore, acute D1 receptor blockade (using SCH39166) decreased the exaggerated psychomotor response to d-amphetamine in haloperidol-pretreated rats, whereas acute D2 receptor blockade (using sulpiride) enhanced it. Thus, after discontinuation of antipsychotic treatment, D1- and D2-mediated transmission differentially modulate the expression of a supersensitive response to d-amphetamine. This supersensitive behavioural response was accompanied by enhanced GSK3β activity and suppressed ERK1/2 activity in the nucleus accumbens (but not caudate-putamen), suggesting increased mesolimbic D2 transmission. Finally, after discontinuing haloperidol treatment, neither increasing ventral midbrain dopamine impulse flow nor infusing d-amphetamine into the cerebral ventricles triggered the expression of already established dopamine supersensitivity, suggesting that peripheral effects are required. Thus, while dopamine receptor-mediated signalling regulates the expression of antipsychotic-evoked dopamine supersensitivity, a simple increase in central dopamine neurotransmission is insufficient to trigger this supersensitivity.
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Affiliation(s)
- Alice Servonnet
- Department of Neurosciences, Faculty of Medicine, Université de Montréal, 2900 Edouard-Montpetit boulevard, Montreal, H3T 1J4, Quebec, Canada.
| | - Florence Allain
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, 2900 Edouard-Montpetit boulevard, Montreal, H3T 1J4, Quebec, Canada
| | - Alice Gravel-Chouinard
- Department of Neurosciences, Faculty of Medicine, Université de Montréal, 2900 Edouard-Montpetit boulevard, Montreal, H3T 1J4, Quebec, Canada
| | - Giovanni Hernandez
- Department of Neurosciences, Faculty of Medicine, Université de Montréal, 2900 Edouard-Montpetit boulevard, Montreal, H3T 1J4, Quebec, Canada; Faculty of Pharmacy, Université de Montréal, 2900 Edouard-Montpetit boulevard, Montreal, H3T 1J4, Quebec, Canada
| | - Casey Bourdeau Caporuscio
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, 2900 Edouard-Montpetit boulevard, Montreal, H3T 1J4, Quebec, Canada
| | - Mathilde Legrix
- Department of Neurosciences, Faculty of Medicine, Université de Montréal, 2900 Edouard-Montpetit boulevard, Montreal, H3T 1J4, Quebec, Canada
| | - Daniel Lévesque
- Faculty of Pharmacy, Université de Montréal, 2900 Edouard-Montpetit boulevard, Montreal, H3T 1J4, Quebec, Canada
| | - Pierre-Paul Rompré
- Department of Neurosciences, Faculty of Medicine, Université de Montréal, 2900 Edouard-Montpetit boulevard, Montreal, H3T 1J4, Quebec, Canada
| | - Anne-Noël Samaha
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, 2900 Edouard-Montpetit boulevard, Montreal, H3T 1J4, Quebec, Canada; Groupe de recherche sur le système nerveux central, Faculty of Medicine, Université de Montréal, 2900 Edouard-Montpetit boulevard, Montrea, H3T 1J4, Quebec, Canada.
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6
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Bhimani RV, Vik M, Wakabayashi KT, Szalkowski C, Bass CE, Park J. Distinct dose-dependent effects of methamphetamine on real-time dopamine transmission in the rat nucleus accumbens and behaviors. J Neurochem 2021; 158:865-879. [PMID: 34265079 PMCID: PMC8376794 DOI: 10.1111/jnc.15470] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 07/07/2021] [Accepted: 07/07/2021] [Indexed: 01/17/2023]
Abstract
Methamphetamine (METH) is a potent psychostimulant that exerts many of its physiological and psychomotor effects by increasing extracellular dopamine (DA) concentrations in limbic brain regions. While several studies have focused on how potent, neurotoxic doses of METH augment or attenuate DA transmission, the acute effects of lower and behaviorally activating doses of METH on modulating DA regulation (release and clearance) through DA D2 autoreceptors and transporters remain to be elucidated. In this study, we investigated how systemic administration of escalating, subneurotoxic doses of METH (0.5-5 mg/kg, IP) alter extracellular DA regulation in the nucleus accumbens (NAc), in both anesthetized and awake-behaving rats through the use of in vivo fast-scan cyclic voltammetry. Pharmacological, electrochemical, and behavioral evidence show that lower doses (≤2.0 mg/kg, IP) of METH enhance extracellular phasic DA concentrations and locomotion as well as stereotypies. In contrast, higher doses (≥5.0 mg/kg) further increase both phasic and baseline DA concentrations and stereotypies but decrease horizontal locomotion. Importantly, our results suggest that acute METH-induced enhancement of extracellular DA concentrations dose dependently activates D2 autoreceptors. Therefore, these different METH dose-dependent effects on mesolimbic DA transmission may distinctly impact METH-induced behavioral changes. This study provides valuable insights regarding how low METH doses alter DA transmission and paves the way for future clinical studies on the reinforcing effects of METH.
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Affiliation(s)
- Rohan V. Bhimani
- Neuroscience Program, University at Buffalo, State University of New York, Buffalo, New York 14214-3005, USA
| | - Megan Vik
- Department of Biotechnical and Clinical Laboratory Sciences, University at Buffalo, State University of New York, Buffalo, New York 14214-3005, USA
| | - Ken T. Wakabayashi
- Department of Biotechnical and Clinical Laboratory Sciences, University at Buffalo, State University of New York, Buffalo, New York 14214-3005, USA
- Department of Pharmacology and Toxicology, University at Buffalo, State University of New York, Buffalo, New York 14214-3005, USA
| | - Caitlin Szalkowski
- Department of Biotechnical and Clinical Laboratory Sciences, University at Buffalo, State University of New York, Buffalo, New York 14214-3005, USA
| | - Caroline E. Bass
- Department of Pharmacology and Toxicology, University at Buffalo, State University of New York, Buffalo, New York 14214-3005, USA
| | - Jinwoo Park
- Neuroscience Program, University at Buffalo, State University of New York, Buffalo, New York 14214-3005, USA
- Department of Biotechnical and Clinical Laboratory Sciences, University at Buffalo, State University of New York, Buffalo, New York 14214-3005, USA
- Department of Pharmacology and Toxicology, University at Buffalo, State University of New York, Buffalo, New York 14214-3005, USA
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7
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Torres DJ, Yorgason JT, Mitchell CC, Hagiwara A, Andres MA, Kurokawa S, Steffensen SC, Bellinger FP. Selenoprotein P Modulates Methamphetamine Enhancement of Vesicular Dopamine Release in Mouse Nucleus Accumbens Via Dopamine D2 Receptors. Front Neurosci 2021; 15:631825. [PMID: 33927588 PMCID: PMC8076559 DOI: 10.3389/fnins.2021.631825] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Accepted: 03/19/2021] [Indexed: 12/25/2022] Open
Abstract
Dopamine (DA) transmission plays a critical role in processing rewarding and pleasurable stimuli. Increased synaptic DA release in the nucleus accumbens (NAc) is a central component of the physiological effects of drugs of abuse. The essential trace element selenium mitigates methamphetamine-induced neurotoxicity. Selenium can also alter DA production and turnover. However, studies have not directly addressed the role of selenium in DA neurotransmission. Selenoprotein P (SELENOP1) requires selenium for synthesis and transports selenium to the brain, in addition to performing other functions. We investigated whether SELENOP1 directly impacts (1) DA signaling and (2) the dopaminergic response to methamphetamine. We used fast-scan cyclic voltammetry to investigate DA transmission and the response to methamphetamine in NAc slices from C57/BL6J SELENOP1 KO mice. Recordings from SELENOP1 KO mouse slices revealed reduced levels of evoked DA release and slower DA uptake rates. Methamphetamine caused a dramatic increase in vesicular DA release in SELENOP1 KO mice not observed in wild-type controls. This elevated response was attenuated by SELENOP1 application through a selenium-independent mechanism involving SELENOP1-apolipoprotein E receptor 2 (ApoER2) interaction to promote dopamine D2 receptor (D2R) function. In wild-type mice, increased vesicular DA release in response to methamphetamine was revealed by blocking D2R activation, indicating that the receptor suppresses the methamphetamine-induced vesicular increase. Our data provide evidence of a direct physiological role for SELENOP1 in the dopaminergic response to methamphetamine and suggest a signaling role for the protein in DA transmission.
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Affiliation(s)
- Daniel J Torres
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawai'i at Mânoa, Honolulu, HI, United States.,Pacific Biosciences Research Center, University of Hawai'i at Mânoa, Honolulu, HI, United States
| | - Jordan T Yorgason
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT, United States
| | - Catherine C Mitchell
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawai'i at Mânoa, Honolulu, HI, United States
| | - Ayaka Hagiwara
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawai'i at Mânoa, Honolulu, HI, United States
| | - Marilou A Andres
- Pacific Biosciences Research Center, University of Hawai'i at Mânoa, Honolulu, HI, United States
| | | | - Scott C Steffensen
- Department of Psychology, Brigham Young University, Provo, UT, United States
| | - Frederick P Bellinger
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawai'i at Mânoa, Honolulu, HI, United States
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8
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Evolution of in vivo dopamine monitoring techniques. Pharmacol Biochem Behav 2020; 200:173078. [PMID: 33278398 DOI: 10.1016/j.pbb.2020.173078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 11/06/2020] [Accepted: 11/18/2020] [Indexed: 01/01/2023]
Abstract
The brain dopamine system is central to numerous behavioral processes, including movement, learning, and motivation. Accordingly, disruptions of this neural system underlie numerous neurological and psychiatric disorders. Current understanding of how dopamine neurotransmission contributes to behavior and its dysfunction has been driven by technological advancements that permit spatiotemporally-defined measurements of dopaminergic signaling in behaving animals. In this review, we will discuss the evolution of in vivo neural monitoring technologies for measuring dopamine neuron function. We focus on the dopamine system for two reasons: (1) the central role of dopamine neurotransmission in normal behavior and disease, and (2) dopamine neuron measurements have long been at the forefront of in vivo neural monitoring technologies. We will provide a brief overview of standard techniques for monitoring dopamine function, including electrophysiology, microdialysis, and voltammetry. Then, we will discuss recent advancements in optical technologies using genetically-encoded fluorescent proteins (GEFPs), including a critical evaluation of their advantages and limitations.
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9
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Nolan SO, Zachry JE, Johnson AR, Brady LJ, Siciliano CA, Calipari ES. Direct dopamine terminal regulation by local striatal microcircuitry. J Neurochem 2020; 155:475-493. [PMID: 32356315 DOI: 10.1111/jnc.15034] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 04/20/2020] [Accepted: 04/22/2020] [Indexed: 02/06/2023]
Abstract
Regulation of axonal dopamine release by local microcircuitry is at the hub of several biological processes that govern the timing and magnitude of signaling events in reward-related brain regions. An important characteristic of dopamine release from axon terminals in the striatum is that it is rapidly modulated by local regulatory mechanisms. These processes can occur via homosynaptic mechanisms-such as presynaptic dopamine autoreceptors and dopamine transporters - as well heterosynaptic mechanisms such as retrograde signaling from postsynaptic cholinergic and dynorphin systems, among others. Additionally, modulation of dopamine release via diffusible messengers, such as nitric oxide and hydrogen peroxide, allows for various metabolic factors to quickly and efficiently regulate dopamine release and subsequent signaling. Here we review how these mechanisms work in concert to influence the timing and magnitude of striatal dopamine signaling, independent of action potential activity at the level of dopaminergic cell bodies in the midbrain, thereby providing a parallel pathway by which dopamine can be modulated. Understanding the complexities of local regulation of dopamine signaling is required for building comprehensive frameworks of how activity throughout the dopamine system is integrated to drive signaling and control behavior.
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Affiliation(s)
- Suzanne O Nolan
- Department of Pharmacology, Vanderbilt University, Nashville, TN, USA
| | - Jennifer E Zachry
- Department of Pharmacology, Vanderbilt University, Nashville, TN, USA
| | - Amy R Johnson
- Department of Pharmacology, Vanderbilt University, Nashville, TN, USA
| | - Lillian J Brady
- Department of Pharmacology, Vanderbilt University, Nashville, TN, USA
| | - Cody A Siciliano
- Department of Pharmacology, Vanderbilt University, Nashville, TN, USA.,Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA.,Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, TN TN, USA
| | - Erin S Calipari
- Department of Pharmacology, Vanderbilt University, Nashville, TN, USA.,Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA.,Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, TN TN, USA.,Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA.,Department of Psychiatry and Behavioral Sciences, Vanderbilt University, Nashville, TN, USA
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10
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Activation of the mGlu 1 metabotropic glutamate receptor has antipsychotic-like effects and is required for efficacy of M 4 muscarinic receptor allosteric modulators. Mol Psychiatry 2020; 25:2786-2799. [PMID: 30116027 PMCID: PMC6588501 DOI: 10.1038/s41380-018-0206-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 06/01/2018] [Accepted: 06/28/2018] [Indexed: 12/25/2022]
Abstract
Recent clinical and preclinical studies suggest that selective activators of the M4 muscarinic acetylcholine receptor have potential as a novel treatment for schizophrenia. M4 activation inhibits striatal dopamine release by mobilizing endocannabinoids, providing a mechanism for local effects on dopamine signaling in the striatum but not in extrastriatal areas. G protein-coupled receptors (GPCRs) typically induce endocannabinoid release through activation of Gαq/11-type G proteins whereas M4 transduction occurs through Gαi/o-type G proteins. We now report that the ability of M4 to inhibit dopamine release and induce antipsychotic-like effects in animal models is dependent on co-activation of the Gαq/11-coupled mGlu1 subtype of metabotropic glutamate (mGlu) receptor. This is especially interesting in light of recent findings that multiple loss of function single nucleotide polymorphisms (SNPs) in the human gene encoding mGlu1 (GRM1) are associated with schizophrenia, and points to GRM1/mGlu1 as a gene within the "druggable genome" that could be targeted for the treatment of schizophrenia. Herein, we report that potentiation of mGlu1 signaling following thalamo-striatal stimulation is sufficient to inhibit striatal dopamine release, and that a novel mGlu1 positive allosteric modulator (PAM) exerts robust antipsychotic-like effects through an endocannabinoid-dependent mechanism. However, unlike M4, mGlu1 does not directly inhibit dopamine D1 receptor signaling and does not reduce motivational responding. Taken together, these findings highlight a novel mechanism of cross talk between mGlu1 and M4 and demonstrate that highly selective mGlu1 PAMs may provide a novel strategy for the treatment of positive symptoms associated with schizophrenia.
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11
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How Important Is the Use of Cocaine and Amphetamines in the Development of Parkinson Disease? A Computational Study. Neurotox Res 2019; 37:724-731. [DOI: 10.1007/s12640-019-00149-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 11/18/2019] [Accepted: 11/29/2019] [Indexed: 11/25/2022]
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12
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Lebowitz JJ, Khoshbouei H. Heterogeneity of dopamine release sites in health and degeneration. Neurobiol Dis 2019; 134:104633. [PMID: 31698055 DOI: 10.1016/j.nbd.2019.104633] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 09/12/2019] [Accepted: 10/02/2019] [Indexed: 02/06/2023] Open
Abstract
Despite comprising only ~ 0.001% of all neurons in the human brain, ventral midbrain dopamine neurons exert a profound influence on human behavior and cognition. As a neuromodulator, dopamine selectively inhibits or enhances synaptic signaling to coordinate neural output for action, attention, and affect. Humans invariably lose brain dopamine during aging, and this can be exacerbated in disease states such as Parkinson's Disease. Further, it is well established in multiple disease states that cell loss is selective for a subset of highly sensitive neurons within the nigrostriatal dopamine tract. Regional differences in dopamine tone are regulated pre-synaptically, with subcircuits of projecting dopamine neurons exhibiting distinct molecular and physiological signatures. Specifically, proteins at dopamine release sites that synthesize and package cytosolic dopamine, modulate its release and reuptake, and alter neuronal excitability show regional differences that provide linkages to the observed sensitivity to neurodegeneration. The aim of this review is to outline the major components of dopamine homeostasis at neurotransmitter release sites and describe the regional differences most relevant to understanding why some, but not all, dopamine neurons exhibit heightened vulnerability to neurodegeneration.
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Affiliation(s)
- Joseph J Lebowitz
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL 32610, USA
| | - Habibeh Khoshbouei
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL 32610, USA.
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13
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Abstract
There is a plethora of amphetamine derivatives exerting stimulant, euphoric, anti-fatigue, and hallucinogenic effects; all structural properties allowing these effects are contained within the amphetamine structure. In the first part of this review, the interaction of amphetamine with the dopamine transporter (DAT), crucially involved in its behavioral effects, is covered, as well as the role of dopamine synthesis, the vesicular monoamine transporter VMAT2, and organic cation 3 transporter (OCT3). The second part deals with requirements in amphetamine's effect on the kinases PKC, CaMKII, and ERK, whereas the third part focuses on where we are in developing anti-amphetamine therapeutics. Thus, treatments are discussed that target DAT, VMAT2, PKC, CaMKII, and OCT3. As is generally true for the development of therapeutics for substance use disorder, there are multiple preclinically promising specific compounds against (meth)amphetamine, for which further development and clinical trials are badly needed.
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Affiliation(s)
- Maarten E A Reith
- Department of Psychiatry, New York University School of Medicine, New York, NY, USA.
| | - Margaret E Gnegy
- Department of Pharmacology, University of Michigan School of Medicine, Ann Arbor, MI, USA
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14
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Bernstein DL, Badve PS, Barson JR, Bass CE, España RA. Hypocretin receptor 1 knockdown in the ventral tegmental area attenuates mesolimbic dopamine signaling and reduces motivation for cocaine. Addict Biol 2018; 23:1032-1045. [PMID: 28971565 DOI: 10.1111/adb.12553] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 08/01/2017] [Accepted: 08/03/2017] [Indexed: 01/24/2023]
Abstract
The hypocretin receptor 1 (HCRTr1) is a critical participant in the regulation of motivated behavior. Previous observations demonstrate that acute pharmacological blockade of HCRTr1 disrupts dopamine (DA) signaling and the motivation for cocaine when delivered systemically or directly into the ventral tegmental area (VTA). To further examine the involvement of HCRTr1 in regulating reward and reinforcement processing, we employed an adeno-associated virus to express a short hairpin RNA designed to knock down HCRTr1. We injected virus into the VTA and examined the effects of HCRTr1 knockdown on cocaine self-administration and DA signaling in the nucleus accumbens (NAc) core. We determined that the viral approach was effective at reducing HCRTr1 expression without affecting the expression of hypocretin receptor 2 or DA-related mRNAs. We next examined the effects of HCRTr1 knockdown on cocaine self-administration, observing delayed acquisition under a fixed-ratio schedule and reduced motivation for cocaine under a progressive ratio schedule. These effects did not appear to be associated with alterations in sleep/wake activity. Using fast-scan cyclic voltammetry, we then examined whether HCRTr1 knockdown alters DA signaling dynamics in the NAc core. We observed reduced DA release and slower uptake rate as well as attenuated cocaine-induced DA uptake inhibition in rats with knockdown of HCRTr1. These observations indicate that HCRTr1 within the VTA influence the motivation for cocaine, likely via alterations in DA signaling in the NAc.
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Affiliation(s)
- David L. Bernstein
- Department of Neurobiology and Anatomy; Drexel University College of Medicine; Philadelphia PA USA
| | - Preeti S. Badve
- Department of Neurobiology and Anatomy; Drexel University College of Medicine; Philadelphia PA USA
| | - Jessica R. Barson
- Department of Neurobiology and Anatomy; Drexel University College of Medicine; Philadelphia PA USA
| | - Caroline E. Bass
- Department of Pharmacology and Toxicology, Jacobs School of Medicine; State University of New York at Buffalo; Buffalo NY USA
| | - Rodrigo A. España
- Department of Neurobiology and Anatomy; Drexel University College of Medicine; Philadelphia PA USA
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15
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Engineered D2R Variants Reveal the Balanced and Biased Contributions of G-Protein and β-Arrestin to Dopamine-Dependent Functions. Neuropsychopharmacology 2018; 43:1164-1173. [PMID: 29068002 PMCID: PMC5854808 DOI: 10.1038/npp.2017.254] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 09/26/2017] [Accepted: 10/16/2017] [Indexed: 01/09/2023]
Abstract
The dopamine D2 receptor (D2R), like many G-protein-coupled receptors, signals through G-protein- and β-arrestin-dependent pathways. Preferential activation of one of these pathways is termed functional selectivity or biased signaling and is a promising therapeutic strategy. Though biased signaling through D2Rs has been demonstrated, acquiring the mechanistic details of biased D2R/G-protein and D2R/β-arrestin signaling in vivo has been challenging because of the lack of techniques that specifically target these interactions in discrete cell populations. To address this question, we employed a cell type-specific viral expression approach to restore D2R variants that preferentially engage either G-protein or β-arrestin signaling in 'indirect pathway' medium spiny neurons (iMSNs), because of their central role in dopamine circuitry. We found that the effect of haloperidol antagonism on D2R metabolic signaling events is largely mediated by acute blockade of D2R/G-protein signaling. We show that a D2R-driven behavior, nestlet shredding, is similarly driven by D2R/G-protein signaling. On the other hand, D2R-driven locomotion and rearing require coordinated D2R/G-protein and D2R/β-arrestin signaling. The acute locomotor response to amphetamine and cocaine similarly depend on both G-protein and β-arrestin D2R signaling. Surprisingly, another psychotropic drug, phencyclidine, displayed a selective D2R/β-arrestin potentiation of locomotion. These findings highlight how D2R mostly relies upon balanced G-protein and β-arrestin signaling in iMSNs. However, the response to haloperidol and phencyclidine indicates that normal D2R signaling homeostasis can be dramatically altered, indicating that targeting a specific D2R signal transduction pathway could allow for more precise modulation of dopamine circuit function.
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16
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Faraone SV. The pharmacology of amphetamine and methylphenidate: Relevance to the neurobiology of attention-deficit/hyperactivity disorder and other psychiatric comorbidities. Neurosci Biobehav Rev 2018; 87:255-270. [PMID: 29428394 DOI: 10.1016/j.neubiorev.2018.02.001] [Citation(s) in RCA: 309] [Impact Index Per Article: 51.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 01/25/2018] [Accepted: 02/05/2018] [Indexed: 12/20/2022]
Abstract
Psychostimulants, including amphetamines and methylphenidate, are first-line pharmacotherapies for individuals with attention-deficit/hyperactivity disorder (ADHD). This review aims to educate physicians regarding differences in pharmacology and mechanisms of action between amphetamine and methylphenidate, thus enhancing physician understanding of psychostimulants and their use in managing individuals with ADHD who may have comorbid psychiatric conditions. A systematic literature review of PubMed was conducted in April 2017, focusing on cellular- and brain system-level effects of amphetamine and methylphenidate. The primary pharmacologic effect of both amphetamine and methylphenidate is to increase central dopamine and norepinephrine activity, which impacts executive and attentional function. Amphetamine actions include dopamine and norepinephrine transporter inhibition, vesicular monoamine transporter 2 (VMAT-2) inhibition, and monoamine oxidase activity inhibition. Methylphenidate actions include dopamine and norepinephrine transporter inhibition, agonist activity at the serotonin type 1A receptor, and redistribution of the VMAT-2. There is also evidence for interactions with glutamate and opioid systems. Clinical implications of these actions in individuals with ADHD with comorbid depression, anxiety, substance use disorder, and sleep disturbances are discussed.
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Affiliation(s)
- Stephen V Faraone
- Departments of Psychiatry and of Neuroscience and Physiology, State University of New York (SUNY) Upstate Medical University, Syracuse, NY, United States; K.G. Jebsen Centre for Research on Neuropsychiatric Disorders, University of Bergen, Bergen, Norway.
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17
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Schuweiler D, Athens J, Thompson J, Vazhayil S, Garris P. Effects of an acute therapeutic or rewarding dose of amphetamine on acquisition of Pavlovian autoshaping and ventral striatal dopamine signaling. Behav Brain Res 2018; 336:191-203. [DOI: 10.1016/j.bbr.2017.09.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 07/28/2017] [Accepted: 09/01/2017] [Indexed: 12/16/2022]
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18
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Yapo C, Nair AG, Clement L, Castro LR, Hellgren Kotaleski J, Vincent P. Detection of phasic dopamine by D1 and D2 striatal medium spiny neurons. J Physiol 2017; 595:7451-7475. [PMID: 28782235 PMCID: PMC5730852 DOI: 10.1113/jp274475] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Accepted: 07/10/2017] [Indexed: 12/15/2022] Open
Abstract
KEY POINTS Brief dopamine events are critical actors of reward-mediated learning in the striatum; the intracellular cAMP-protein kinase A (PKA) response of striatal medium spiny neurons to such events was studied dynamically using a combination of biosensor imaging in mouse brain slices and in silico simulations. Both D1 and D2 medium spiny neurons can sense brief dopamine transients in the sub-micromolar range. While dopamine transients profoundly change cAMP levels in both types of medium spiny neurons, the PKA-dependent phosphorylation level remains unaffected in D2 neurons. At the level of PKA-dependent phosphorylation, D2 unresponsiveness depends on protein phosphatase-1 (PP1) inhibition by DARPP-32. Simulations suggest that D2 medium spiny neurons could detect transient dips in dopamine level. ABSTRACT The phasic release of dopamine in the striatum determines various aspects of reward and action selection, but the dynamics of the dopamine effect on intracellular signalling remains poorly understood. We used genetically encoded FRET biosensors in striatal brain slices to quantify the effect of transient dopamine on cAMP or PKA-dependent phosphorylation levels, and computational modelling to further explore the dynamics of this signalling pathway. Medium-sized spiny neurons (MSNs), which express either D1 or D2 dopamine receptors, responded to dopamine by an increase or a decrease in cAMP, respectively. Transient dopamine showed similar sub-micromolar efficacies on cAMP in both D1 and D2 MSNs, thus challenging the commonly accepted notion that dopamine efficacy is much higher on D2 than on D1 receptors. However, in D2 MSNs, the large decrease in cAMP level triggered by transient dopamine did not translate to a decrease in PKA-dependent phosphorylation level, owing to the efficient inhibition of protein phosphatase 1 by DARPP-32. Simulations further suggested that D2 MSNs can also operate in a 'tone-sensing' mode, allowing them to detect transient dips in basal dopamine. Overall, our results show that D2 MSNs may sense much more complex patterns of dopamine than previously thought.
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Affiliation(s)
- Cedric Yapo
- CNRS, UMR8256 “Biological Adaptation and Ageing”Institut de Biologie Paris‐Seine (IBPS)F‐75005ParisFrance
- Université Pierre et Marie Curie (UPMC, Paris 6)Sorbonne UniversitésF‐75005ParisFrance
| | - Anu G. Nair
- Science for Life Laboratory, School of Computer Science and CommunicationKTH Royal Institute of Technology10044StockholmSweden
- National Centre for Biological SciencesTata Institute of Fundamental ResearchBangalore560065KarnatakaIndia
- Manipal UniversityManipal576104KarnatakaIndia
| | - Lorna Clement
- CNRS, UMR8256 “Biological Adaptation and Ageing”Institut de Biologie Paris‐Seine (IBPS)F‐75005ParisFrance
| | - Liliana R. Castro
- CNRS, UMR8256 “Biological Adaptation and Ageing”Institut de Biologie Paris‐Seine (IBPS)F‐75005ParisFrance
- Université Pierre et Marie Curie (UPMC, Paris 6)Sorbonne UniversitésF‐75005ParisFrance
| | - Jeanette Hellgren Kotaleski
- Science for Life Laboratory, School of Computer Science and CommunicationKTH Royal Institute of Technology10044StockholmSweden
- Department of NeuroscienceKarolinska Institutet17177SolnaSweden
| | - Pierre Vincent
- CNRS, UMR8256 “Biological Adaptation and Ageing”Institut de Biologie Paris‐Seine (IBPS)F‐75005ParisFrance
- Université Pierre et Marie Curie (UPMC, Paris 6)Sorbonne UniversitésF‐75005ParisFrance
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19
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Compromised Dopaminergic Encoding of Reward Accompanying Suppressed Willingness to Overcome High Effort Costs Is a Prominent Prodromal Characteristic of the Q175 Mouse Model of Huntington's Disease. J Neurosci 2017; 36:4993-5002. [PMID: 27147652 DOI: 10.1523/jneurosci.0135-16.2016] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 03/15/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Huntington's disease (HD) is a heritable neurodegenerative disorder caused by expansion of CAG (glutamine) repeats in the HTT gene. A prodromal stage characterized by psychiatric disturbances normally precedes primary motor symptoms and suppressed motivation represents one of the earliest and most common psychiatric symptoms. Although dopamine in the nucleus accumbens (NAc) critically regulates motivation and altered dopamine signaling is implicated in HD, the nature of dopaminergic deficits and contribution to symptoms in HD is poorly understood. We therefore tested whether altered NAc dopamine release accompanies motivational deficits in the Q175 knock-in HD mouse model. Q175 mice express a CAG expansion of the human mutant huntingtin allele in the native mouse genome and gradually manifest symptoms late in life, closely mimicking the genotypic context and disease progression in human HD. Sub-second extracellular dopamine release dynamics were monitored using fast-scan cyclic voltammetry, whereas motivation was assessed using a progressive ratio reinforcement schedule. As the response ratio (lever presses per reward) escalated, Q175 mice exerted less effort to earn fewer rewards versus wild-type (WT). Moreover, dopamine released at reward delivery dynamically encoded increasing reward cost in WT but not Q175 mice. Deficits were specific to situations of high effortful demand as no difference was observed in locomotion, free feeding, hedonic processing, or reward seeking when the response requirement was low. This compromised dopaminergic encoding of reward delivery coincident with suppressed motivation to work for reward in Q175 mice provides novel, neurobiological insight into an established and clinically relevant endophenotype of prodromal HD. SIGNIFICANCE STATEMENT Psychiatric impairments in Huntington's disease (HD) typically manifest early in disease progression, before motor deficits. However, the neurobiological factors contributing to psychiatric symptoms are poorly understood. We used a mouse HD model and assessed whether impaired dopamine release in the nucleus accumbens (NAc), a brain region critical to goal-directed behaviors, accompanies motivational deficits, one of the most common early HD symptoms. HD mice exhibited blunted motivation to work for food reward coincident with diminished dopamine release to reward receipt. Motivational and NAc dopaminergic deficits were not associated with gross motor deficits or impaired food seeking when effortful demands were low. This work identifies a specific prodromal HD phenotype associated with a prominent and previously unidentified neurobiological impairment.
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20
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Majdak P, Ossyra JR, Ossyra JM, Cobert AJ, Hofmann GC, Tse S, Panozzo B, Grogan EL, Sorokina A, Rhodes JS. A new mouse model of ADHD for medication development. Sci Rep 2016; 6:39472. [PMID: 27996970 PMCID: PMC5171883 DOI: 10.1038/srep39472] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 11/21/2016] [Indexed: 11/12/2022] Open
Abstract
ADHD is a major societal problem with increasing incidence and a stagnant track record for treatment advances. A lack of appropriate animal models has partly contributed to the incremental advance of this field. Hence, our goal was to generate a novel mouse model that could be useful for ADHD medication development. We reasoned that hyperactivity is a core feature of ADHD that could easily be bred into a population, but to what extent other hallmark features of ADHD would appear as correlated responses was unknown. Hence, starting from a heterogeneous population, we applied within-family selection over 16 generations to produce a High-Active line, while simultaneously maintaining an unselected line to serve as the Control. We discovered that the High-Active line demonstrated motor impulsivity in two different versions of the Go/No-go test, which was ameliorated with a low dose of amphetamine, and further displayed hypoactivation of the prefrontal cortex and dysregulated cerebellar vermal activation as indexed by c-Fos immunohistochemical staining. We conclude that the High-Active line represents a valid model for the Hyperactive-Impulsive subtype of ADHD and therefore may be used in future studies to advance our understanding of the etiology of ADHD and screen novel compounds for its treatment.
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Affiliation(s)
- Petra Majdak
- The Neuroscience Program, University of Illinois, IL, USA.,The Beckman Institute for Advanced Science and Technology, University of Illinois, IL, USA
| | - John R Ossyra
- Oak Ridge National Laboratory, University of Tennessee, Knoxville, TN, USA
| | - Jessica M Ossyra
- College of Engineering, University of Tennessee, Knoxville, TN, USA
| | - Adam J Cobert
- Department of Food Science and Technology, University of California, Davis, CA, USA
| | | | - Stephen Tse
- The Beckman Institute for Advanced Science and Technology, University of Illinois, IL, USA
| | - Brent Panozzo
- The Beckman Institute for Advanced Science and Technology, University of Illinois, IL, USA
| | - Elizabeth L Grogan
- The Beckman Institute for Advanced Science and Technology, University of Illinois, IL, USA
| | - Anastassia Sorokina
- The Beckman Institute for Advanced Science and Technology, University of Illinois, IL, USA
| | - Justin S Rhodes
- The Neuroscience Program, University of Illinois, IL, USA.,The Beckman Institute for Advanced Science and Technology, University of Illinois, IL, USA.,Department of Psychology, University of Illinois, IL, USA
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21
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Beaulieu JM. Converging evidence for regulation of dopamine neurotransmission by lithium: An Editorial Highlight for 'Chronic lithium treatment rectifies maladaptive dopamine release in the nucleus accumbens'. J Neurochem 2016; 139:520-522. [PMID: 27753085 DOI: 10.1111/jnc.13846] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Revised: 09/12/2016] [Accepted: 09/13/2016] [Indexed: 11/28/2022]
Abstract
Read the highlighted article 'Chronic lithium treatment rectifies maladaptive dopamine release in the nucleus accumbens' on page 576.
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Affiliation(s)
- Jean-Martin Beaulieu
- Department of Psychiatry and Neuroscience, Faculty of Medicine, Université Laval, Québec-City, QC, Canada.,Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
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22
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Can A, Frost DO, Cachope R, Cheer JF, Gould TD. Chronic lithium treatment rectifies maladaptive dopamine release in the nucleus accumbens. J Neurochem 2016; 139:576-585. [PMID: 27513916 DOI: 10.1111/jnc.13769] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 06/21/2016] [Accepted: 07/26/2016] [Indexed: 12/15/2022]
Abstract
Chronic lithium treatment effectively reduces behavioral phenotypes of mania in humans and rodents. The mechanisms by which lithium exerts these actions are poorly understood. Pre-clinical and clinical evidence have implicated increased mesolimbic dopamine (DA) neurotransmission with mania. We used fast-scan cyclic voltammetry to characterize changes in extracellular DA concentrations in the nucleus accumbens (NAc) core evoked by 20 and 60 Hz electrical stimulation of the ventral tegmental area (VTA) in C57BL6/J mice treated either acutely or chronically with lithium. The effects of chronic lithium treatment on the availability of DA for release were assessed by depleting readily releasable DA using short inter-train intervals, or administering d-amphetamine acutely to mobilize readily releasable DA. Chronic, but not acute, lithium treatment decreased the amplitude of DA responses in the NAc following 60 Hz pulse train stimulation. Neither lithium treatment altered the kinetics of DA release or reuptake. Chronic treatment did not impact the progressive reduction in the amplitude of DA responses when, using 20 or 60 Hz pulse trains, the VTA was stimulated every 6 s to deplete DA. Specifically, the amplitude of DA responses to 60 Hz pulse trains was initially reduced compared to control mice, but by the fifth pulse train, there was no longer a treatment effect. However, chronic lithium treatment attenuated d-amphetamine-induced increases in DA responses to 20 Hz pulse trains stimulation. Our data suggest that long-term administration of lithium may ameliorate mania phenotypes by normalizing the readily releasable DA pool in VTA axon terminals in the NAc. Read the Editorial Highlight for this article on Page 520.
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Affiliation(s)
- Adem Can
- Department of Psychiatry, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Douglas O Frost
- Department of Psychiatry, University of Maryland School of Medicine, Baltimore, Maryland, USA.,Department of Pharmacology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | | | - Joseph F Cheer
- Department of Psychiatry, University of Maryland School of Medicine, Baltimore, Maryland, USA.,Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Todd D Gould
- Department of Psychiatry, University of Maryland School of Medicine, Baltimore, Maryland, USA.,Department of Pharmacology, University of Maryland School of Medicine, Baltimore, Maryland, USA.,Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
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23
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Bobak MJ, Weber MW, Doellman MA, Schuweiler DR, Athens JM, Juliano SA, Garris PA. Modafinil Activates Phasic Dopamine Signaling in Dorsal and Ventral Striata. J Pharmacol Exp Ther 2016; 359:460-470. [PMID: 27733628 DOI: 10.1124/jpet.116.236000] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 10/11/2016] [Indexed: 11/22/2022] Open
Abstract
Modafinil (MOD) exhibits therapeutic efficacy for treating sleep and psychiatric disorders; however, its mechanism is not completely understood. Compared with other psychostimulants inhibiting dopamine (DA) uptake, MOD weakly interacts with the dopamine transporter (DAT) and modestly elevates striatal dialysate DA, suggesting additional targets besides DAT. However, the ability of MOD to induce wakefulness is abolished with DAT knockout, conversely suggesting that DAT is necessary for MOD action. Another psychostimulant target, but one not established for MOD, is activation of phasic DA signaling. This communication mode during which burst firing of DA neurons generates rapid changes in extracellular DA, the so-called DA transients, is critically implicated in reward learning. Here, we investigate MOD effects on phasic DA signaling in the striatum of urethane-anesthetized rats with fast-scan cyclic voltammetry. We found that MOD (30-300 mg/kg i.p.) robustly increases the amplitude of electrically evoked phasic-like DA signals in a time- and dose-dependent fashion, with greater effects in dorsal versus ventral striata. MOD-induced enhancement of these electrically evoked amplitudes was mediated preferentially by increased DA release compared with decreased DA uptake. Principal component regression of nonelectrically evoked recordings revealed negligible changes in basal DA with high-dose MOD (300 mg/kg i.p.). Finally, in the presence of the D2 DA antagonist, raclopride, low-dose MOD (30 mg/kg i.p.) robustly elicited DA transients in dorsal and ventral striata. Taken together, these results suggest that activation of phasic DA signaling is an important mechanism underlying the clinical efficacy of MOD.
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Affiliation(s)
- Martin J Bobak
- School of Biological Sciences, Illinois State University, Normal, Illinois
| | - Matthew W Weber
- School of Biological Sciences, Illinois State University, Normal, Illinois
| | - Melissa A Doellman
- School of Biological Sciences, Illinois State University, Normal, Illinois
| | | | - Jeana M Athens
- School of Biological Sciences, Illinois State University, Normal, Illinois
| | - Steven A Juliano
- School of Biological Sciences, Illinois State University, Normal, Illinois
| | - Paul A Garris
- School of Biological Sciences, Illinois State University, Normal, Illinois
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24
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Sulzer D, Cragg SJ, Rice ME. Striatal dopamine neurotransmission: regulation of release and uptake. ACTA ACUST UNITED AC 2016; 6:123-148. [PMID: 27141430 DOI: 10.1016/j.baga.2016.02.001] [Citation(s) in RCA: 236] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Dopamine (DA) transmission is governed by processes that regulate release from axonal boutons in the forebrain and the somatodendritic compartment in midbrain, and by clearance by the DA transporter, diffusion, and extracellular metabolism. We review how axonal DA release is regulated by neuronal activity and by autoreceptors and heteroreceptors, and address how quantal release events are regulated in size and frequency. In brain regions densely innervated by DA axons, DA clearance is due predominantly to uptake by the DA transporter, whereas in cortex, midbrain, and other regions with relatively sparse DA inputs, the norepinephrine transporter and diffusion are involved. We discuss the role of DA uptake in restricting the sphere of influence of DA and in temporal accumulation of extracellular DA levels upon successive action potentials. The tonic discharge activity of DA neurons may be translated into a tonic extracellular DA level, whereas their bursting activity can generate discrete extracellular DA transients.
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Affiliation(s)
- David Sulzer
- Depts of Psychiatry, Neurology, & Pharmacology, NY State Psychiatric Institute, Columbia University, New York, NY, USA
| | - Stephanie J Cragg
- Dept Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Margaret E Rice
- Depts of Neurosurgery & Neuroscience and Physiology, New York University School of Medicine, New York, NY, USA
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25
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Covey DP, Bunner KD, Schuweiler DR, Cheer JF, Garris PA. Amphetamine elevates nucleus accumbens dopamine via an action potential-dependent mechanism that is modulated by endocannabinoids. Eur J Neurosci 2016; 43:1661-73. [PMID: 27038339 PMCID: PMC5819353 DOI: 10.1111/ejn.13248] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 03/29/2016] [Indexed: 02/04/2023]
Abstract
The reinforcing effects of abused drugs are mediated by their ability to elevate nucleus accumbens dopamine. Amphetamine (AMPH) was historically thought to increase dopamine by an action potential-independent, non-exocytotic type of release called efflux, involving reversal of dopamine transporter function and driven by vesicular dopamine depletion. Growing evidence suggests that AMPH also acts by an action potential-dependent mechanism. Indeed, fast-scan cyclic voltammetry demonstrates that AMPH activates dopamine transients, reward-related phasic signals generated by burst firing of dopamine neurons and dependent on intact vesicular dopamine. Not established for AMPH but indicating a shared mechanism, endocannabinoids facilitate this activation of dopamine transients by broad classes of abused drugs. Here, using fast-scan cyclic voltammetry coupled to pharmacological manipulations in awake rats, we investigated the action potential and endocannabinoid dependence of AMPH-induced elevations in nucleus accumbens dopamine. AMPH increased the frequency, amplitude and duration of transients, which were observed riding on top of slower dopamine increases. Surprisingly, silencing dopamine neuron firing abolished all AMPH-induced dopamine elevations, identifying an action potential-dependent origin. Blocking cannabinoid type 1 receptors prevented AMPH from increasing transient frequency, similar to reported effects on other abused drugs, but not from increasing transient duration and inhibiting dopamine uptake. Thus, AMPH elevates nucleus accumbens dopamine by eliciting transients via cannabinoid type 1 receptors and promoting the summation of temporally coincident transients, made more numerous, larger and wider by AMPH. Collectively, these findings are inconsistent with AMPH eliciting action potential-independent dopamine efflux and vesicular dopamine depletion, and support endocannabinoids facilitating phasic dopamine signalling as a common action in drug reinforcement.
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Affiliation(s)
- Dan P. Covey
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Kendra D. Bunner
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA
| | - Douglas R. Schuweiler
- School of Biological Sciences, Illinois State University, 210 Julian Hall, Normal, IL 61790-4120, USA
| | - Joseph F. Cheer
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Paul A. Garris
- School of Biological Sciences, Illinois State University, 210 Julian Hall, Normal, IL 61790-4120, USA
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26
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German CL, Baladi MG, McFadden LM, Hanson GR, Fleckenstein AE. Regulation of the Dopamine and Vesicular Monoamine Transporters: Pharmacological Targets and Implications for Disease. Pharmacol Rev 2016; 67:1005-24. [PMID: 26408528 DOI: 10.1124/pr.114.010397] [Citation(s) in RCA: 120] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Dopamine (DA) plays a well recognized role in a variety of physiologic functions such as movement, cognition, mood, and reward. Consequently, many human disorders are due, in part, to dysfunctional dopaminergic systems, including Parkinson's disease, attention deficit hyperactivity disorder, and substance abuse. Drugs that modify the DA system are clinically effective in treating symptoms of these diseases or are involved in their manifestation, implicating DA in their etiology. DA signaling and distribution are primarily modulated by the DA transporter (DAT) and by vesicular monoamine transporter (VMAT)-2, which transport DA into presynaptic terminals and synaptic vesicles, respectively. These transporters are regulated by complex processes such as phosphorylation, protein-protein interactions, and changes in intracellular localization. This review provides an overview of 1) the current understanding of DAT and VMAT2 neurobiology, including discussion of studies ranging from those conducted in vitro to those involving human subjects; 2) the role of these transporters in disease and how these transporters are affected by disease; and 3) and how selected drugs alter the function and expression of these transporters. Understanding the regulatory processes and the pathologic consequences of DAT and VMAT2 dysfunction underlies the evolution of therapeutic development for the treatment of DA-related disorders.
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Affiliation(s)
- Christopher L German
- School of Dentistry (C.L.G., M.G.B., G.R.H., A.E.F.) and Department of Pharmacology and Toxicology (L.M.M., G.R.H.), University of Utah, Salt Lake City, Utah
| | - Michelle G Baladi
- School of Dentistry (C.L.G., M.G.B., G.R.H., A.E.F.) and Department of Pharmacology and Toxicology (L.M.M., G.R.H.), University of Utah, Salt Lake City, Utah
| | - Lisa M McFadden
- School of Dentistry (C.L.G., M.G.B., G.R.H., A.E.F.) and Department of Pharmacology and Toxicology (L.M.M., G.R.H.), University of Utah, Salt Lake City, Utah
| | - Glen R Hanson
- School of Dentistry (C.L.G., M.G.B., G.R.H., A.E.F.) and Department of Pharmacology and Toxicology (L.M.M., G.R.H.), University of Utah, Salt Lake City, Utah
| | - Annette E Fleckenstein
- School of Dentistry (C.L.G., M.G.B., G.R.H., A.E.F.) and Department of Pharmacology and Toxicology (L.M.M., G.R.H.), University of Utah, Salt Lake City, Utah
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27
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Paredes RM, Piccart E, Navaira E, Cruz D, Javors MA, Koek W, Beckstead MJ, Walss-Bass C. Physiological and behavioral effects of amphetamine in BACE1(-/-) mice. GENES BRAIN AND BEHAVIOR 2015; 14:411-8. [PMID: 25912880 DOI: 10.1111/gbb.12222] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 04/17/2015] [Accepted: 04/23/2015] [Indexed: 01/01/2023]
Abstract
β-Site APP-cleaving Enzyme 1 (BACE1) is a protease that has been linked to schizophrenia, a severe mental illness that is potentially characterized by enhanced dopamine (DA) release in the striatum. Here, we used acute amphetamine administration to stimulate neuronal activity and investigated the neurophysiological and locomotor-activity response in BACE1-deficient (BACE1(-/-) ) mice. We measured locomotor activity at baseline and after treatment with amphetamine (3.2 and 10 mg/kg). While baseline locomotor activity did not vary between groups, BACE1(-/-) mice exhibited reduced sensitivity to the locomotor-enhancing effects of amphetamine. Using high-performance liquid chromatography (HPLC) to measure DA and DA metabolites in the striatum, we found no significant differences in BACE1(-/-) compared with wild-type mice. To determine if DA neuron excitability is altered in BACE1(-/-) mice, we performed patch-clamp electrophysiology in putative DA neurons from brain slices that contained the substantia nigra. Pacemaker firing rate was slightly increased in slices from BACE1(-/-) mice. We next measured G protein-coupled potassium currents produced by activation of D2 autoreceptors, which strongly inhibit firing of these neurons. The maximal amplitude and decay times of D2 autoreceptor currents were not altered in BACE1(-/-) mice, indicating no change in D2 autoreceptor-sensitivity and DA transporter-mediated reuptake. However, amphetamine (30 µm)-induced potassium currents produced by efflux of DA were enhanced in BACE1(-/-) mice, perhaps indicating increased vesicular DA content in the midbrain. This suggests a plausible mechanism to explain the decreased sensitivity to amphetamine-induced locomotion, and provides evidence that decreased availability of BACE1 can produce persistent adaptations in the dopaminergic system.
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Affiliation(s)
- R Madelaine Paredes
- Department of Psychiatry, University of Texas Health Science Center, San Antonio
| | - E Piccart
- Department of Psychiatry, University of Texas Health Science Center, San Antonio
| | - E Navaira
- Department of Psychiatry, University of Texas Health Science Center, San Antonio
| | - D Cruz
- Department of Psychiatry, University of Texas Health Science Center, San Antonio
| | - M A Javors
- Department of Psychiatry, University of Texas Health Science Center, San Antonio
| | - W Koek
- Department of Psychiatry, University of Texas Health Science Center, San Antonio
| | - M J Beckstead
- Department of Psychiatry, University of Texas Health Science Center, San Antonio
| | - C Walss-Bass
- Department of Psychiatry and Behavioral Sciences, University of Texas Health Science Center at Houston, Houston, TX, USA
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28
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Mergy MA, Gowrishankar R, Davis GL, Jessen TN, Wright J, Stanwood GD, Hahn MK, Blakely RD. Genetic targeting of the amphetamine and methylphenidate-sensitive dopamine transporter: on the path to an animal model of attention-deficit hyperactivity disorder. Neurochem Int 2014; 73:56-70. [PMID: 24332984 PMCID: PMC4177817 DOI: 10.1016/j.neuint.2013.11.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2013] [Revised: 11/20/2013] [Accepted: 11/23/2013] [Indexed: 12/20/2022]
Abstract
Alterations in dopamine (DA) signaling underlie the most widely held theories of molecular and circuit level perturbations that lead to risk for attention-deficit hyperactivity disorder (ADHD). The DA transporter (DAT), a presynaptic reuptake protein whose activity provides critical support for DA signaling by limiting DA action at pre- and postsynaptic receptors, has been consistently associated with ADHD through pharmacological, behavioral, brain imaging and genetic studies. Currently, the animal models of ADHD exhibit significant limitations, stemming in large part from their lack of construct validity. To remedy this situation, we have pursued the creation of a mouse model derived from a functional nonsynonymous variant in the DAT gene (SLC6A3) of ADHD probands. We trace our path from the identification of these variants to in vitro biochemical and physiological studies to the production of the DAT Val559 mouse model. We discuss our initial findings with these animals and their promise in the context of existing rodent models of ADHD.
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Affiliation(s)
- Marc A Mergy
- Departments of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Raajaram Gowrishankar
- Departments of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Gwynne L Davis
- Departments of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Tammy N Jessen
- Departments of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Jane Wright
- Departments of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Gregg D Stanwood
- Departments of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Maureen K Hahn
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Randy D Blakely
- Departments of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN, USA; Department of Psychiatry, Vanderbilt University School of Medicine, Nashville, TN, USA.
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29
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Sun M, Kaplan SV, Gehringer RC, Limbocker RA, Johnson MA. Localized drug application and sub-second voltammetric dopamine release measurements in a brain slice perfusion device. Anal Chem 2014; 86:4151-6. [PMID: 24734992 PMCID: PMC4018083 DOI: 10.1021/ac5008927] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
The
use of fast scan cyclic voltammetry (FSCV) to measure the release
and uptake of dopamine (DA) as well as other biogenic molecules in
viable brain tissue slices has gained popularity over the last 2 decades.
Brain slices have the advantage of maintaining the functional three-dimensional
architecture of the neuronal network while also allowing researchers
to obtain multiple sets of measurements from a single animal. In this
work, we describe a simple, easy-to-fabricate perfusion device designed
to focally deliver pharmacological agents to brain slices. The device
incorporates a microfluidic channel that runs under the perfusion
bath and a microcapillary that supplies fluid from this channel up
to the slice. We measured electrically evoked DA release in brain
slices before and after the administration of two dopaminergic stimulants,
cocaine and GBR-12909. Measurements were collected at two locations,
one directly over and the other 500 μm away from the capillary
opening. Using this approach, the controlled delivery of drugs to
a confined region of the brain slice and the application of this chamber
to FSCV measurements, were demonstrated. Moreover, the consumption
of drugs was reduced to tens of microliters, which is thousands of
times less than traditional perfusion methods. We expect that this
simply fabricated device will be useful in providing spatially resolved
delivery of drugs with minimum consumption for voltammetric and electrophysiological
studies of a variety of biological tissues both in vitro and ex vivo.
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Affiliation(s)
- Meng Sun
- Department of Chemistry and R. N. Adams Institute for Bioanalytical Chemistry, University of Kansas , Lawrence, Kansas 66045 United States
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30
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Covey DP, Roitman MF, Garris PA. Illicit dopamine transients: reconciling actions of abused drugs. Trends Neurosci 2014; 37:200-10. [PMID: 24656971 DOI: 10.1016/j.tins.2014.02.002] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 01/27/2014] [Accepted: 02/05/2014] [Indexed: 01/03/2023]
Abstract
Phasic increases in brain dopamine are required for cue-directed reward seeking. Although compelling within the framework of appetitive behavior, the view that illicit drugs hijack reward circuits by hyperactivating these dopamine transients is inconsistent with established psychostimulant pharmacology. However, recent work reclassifying amphetamine (AMPH), cocaine, and other addictive dopamine-transporter inhibitors (DAT-Is) supports transient hyperactivation as a unifying hypothesis of abused drugs. We argue here that reclassification also identifies generating burst firing by dopamine neurons as a keystone action. Unlike natural rewards, which are processed by sensory systems, drugs act directly on the brain. Consequently, to mimic natural rewards and exploit reward circuits, dopamine transients must be elicited de novo. Of available drug targets, only burst firing achieves this essential outcome.
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Affiliation(s)
- Dan P Covey
- School of Biological Sciences, Illinois State University, Normal, IL 61790-4120, USA
| | - Mitchell F Roitman
- Department of Psychology, University of Illinois at Chicago, Chicago, IL 60607-7137, USA
| | - Paul A Garris
- School of Biological Sciences, Illinois State University, Normal, IL 61790-4120, USA.
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31
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Gowrishankar R, Hahn MK, Blakely RD. Good riddance to dopamine: roles for the dopamine transporter in synaptic function and dopamine-associated brain disorders. Neurochem Int 2013; 73:42-8. [PMID: 24231471 DOI: 10.1016/j.neuint.2013.10.016] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 10/29/2013] [Accepted: 10/31/2013] [Indexed: 11/25/2022]
Abstract
The neurotransmitter dopamine (DA) plays a critical role in CNS circuits that provide for attention, executive function, reward responses, motivation and movement. DA is inactivated by the cocaine- and amphetamine-sensitive DA transporter (DAT), a protein that also provides a pathway for non-vesicular DA release. After a brief review of DAT function and psychostimulant actions, we consider the importance DAT in relation to the distinct firing patterns of DA neurons that permit awareness of novelty and reward. Finally, we review recent efforts to gather direct support for DAT-linked disorders, with a specific focus on DAT mutations recently identified in subjects with ADHD.
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Affiliation(s)
- Raajaram Gowrishankar
- Vanderbilt International Scholars Program, Vanderbilt University School of Medicine, Nashville, TN 37232-8548, United States; Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-8548, United States
| | - Maureen K Hahn
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-8548, United States; Department of Genetic Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232-8548, United States
| | - Randy D Blakely
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-8548, United States; Department of Psychiatry, Vanderbilt University School of Medicine, Nashville, TN 37232-8548, United States.
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