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Jackson A, Engen PA, Forsyth CB, Shaikh M, Naqib A, Wilber S, Frausto DM, Raeisi S, Green SJ, Bradaric BD, Persons AL, Voigt RM, Keshavarzian A. Intestinal Barrier Dysfunction in the Absence of Systemic Inflammation Fails to Exacerbate Motor Dysfunction and Brain Pathology in a Mouse Model of Parkinson's Disease. Front Neurol 2022; 13:882628. [PMID: 35665034 PMCID: PMC9159909 DOI: 10.3389/fneur.2022.882628] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 04/14/2022] [Indexed: 01/01/2023] Open
Abstract
Introduction Parkinson's disease (PD) is the second most common neurodegenerative disease associated with aging. PD patients have systemic and neuroinflammation which is hypothesized to contribute to neurodegeneration. Recent studies highlight the importance of the gut-brain axis in PD pathogenesis and suggest that gut-derived inflammation can trigger and/or promote neuroinflammation and neurodegeneration in PD. However, it is not clear whether microbiota dysbiosis, intestinal barrier dysfunction, or intestinal inflammation (common features in PD patients) are primary drivers of disrupted gut-brain axis in PD that promote neuroinflammation and neurodegeneration. Objective To determine the role of microbiota dysbiosis, intestinal barrier dysfunction, and colonic inflammation in neuroinflammation and neurodegeneration in a genetic rodent model of PD [α-synuclein overexpressing (ASO) mice]. Methods To distinguish the role of intestinal barrier dysfunction separate from inflammation, low dose (1%) dextran sodium sulfate (DSS) was administered in cycles for 52 days to ASO and control mice. The outcomes assessed included intestinal barrier integrity, intestinal inflammation, stool microbiome community, systemic inflammation, motor function, microglial activation, and dopaminergic neurons. Results Low dose DSS treatment caused intestinal barrier dysfunction (sugar test, histological analysis), intestinal microbiota dysbiosis, mild intestinal inflammation (colon shortening, elevated MPO), but it did not increase systemic inflammation (serum cytokines). However, DSS did not exacerbate motor dysfunction, neuroinflammation (microglial activation), or dopaminergic neuron loss in ASO mice. Conclusion Disruption of the intestinal barrier without overt intestinal inflammation is not associated with worsening of PD-like behavior and pathology in ASO mice.
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Affiliation(s)
- Aeja Jackson
- Rush Medical College, Rush Center for Integrated Microbiome and Chronobiology Research, Rush University Medical Center, Chicago, IL, United States
| | - Phillip A. Engen
- Rush Medical College, Rush Center for Integrated Microbiome and Chronobiology Research, Rush University Medical Center, Chicago, IL, United States
| | - Christopher B. Forsyth
- Rush Medical College, Rush Center for Integrated Microbiome and Chronobiology Research, Rush University Medical Center, Chicago, IL, United States
- Department of Medicine, Rush University Medical Center, Chicago, IL, United States
- Department of Anatomy and Cell Biology, Rush University Medical Center, Chicago, IL, United States
| | - Maliha Shaikh
- Rush Medical College, Rush Center for Integrated Microbiome and Chronobiology Research, Rush University Medical Center, Chicago, IL, United States
| | - Ankur Naqib
- Rush Medical College, Rush Center for Integrated Microbiome and Chronobiology Research, Rush University Medical Center, Chicago, IL, United States
| | - Sherry Wilber
- Rush Medical College, Rush Center for Integrated Microbiome and Chronobiology Research, Rush University Medical Center, Chicago, IL, United States
| | - Dulce M. Frausto
- Rush Medical College, Rush Center for Integrated Microbiome and Chronobiology Research, Rush University Medical Center, Chicago, IL, United States
| | - Shohreh Raeisi
- Rush Medical College, Rush Center for Integrated Microbiome and Chronobiology Research, Rush University Medical Center, Chicago, IL, United States
| | - Stefan J. Green
- Department of Medicine, Rush University Medical Center, Chicago, IL, United States
- Genomics and Microbiome Core Facility, Rush University Medical Center, Chicago, IL, United States
| | - Brinda Desai Bradaric
- Bachelor of Science in Health Sciences Program, College of Health Sciences, Rush University Medical Center, Chicago, IL, United States
- Center for Compulsive Behavior and Addiction, Rush University Medical Center, Chicago, IL, United States
| | - Amanda L. Persons
- Center for Compulsive Behavior and Addiction, Rush University Medical Center, Chicago, IL, United States
- Department of Physician Assistant Studies, Rush University Medical Center, Chicago, IL, United States
| | - Robin M. Voigt
- Rush Medical College, Rush Center for Integrated Microbiome and Chronobiology Research, Rush University Medical Center, Chicago, IL, United States
- Department of Medicine, Rush University Medical Center, Chicago, IL, United States
- Department of Anatomy and Cell Biology, Rush University Medical Center, Chicago, IL, United States
| | - Ali Keshavarzian
- Rush Medical College, Rush Center for Integrated Microbiome and Chronobiology Research, Rush University Medical Center, Chicago, IL, United States
- Department of Medicine, Rush University Medical Center, Chicago, IL, United States
- Department of Anatomy and Cell Biology, Rush University Medical Center, Chicago, IL, United States
- Department of Physiology, Rush University Medical Center, Chicago, IL, United States
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Calma ID, Persons AL, Napier TC. Mitochondrial function influences expression of methamphetamine-induced behavioral sensitization. Sci Rep 2021; 11:24529. [PMID: 34972820 PMCID: PMC8720100 DOI: 10.1038/s41598-021-04301-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 12/13/2021] [Indexed: 12/21/2022] Open
Abstract
Repeated methamphetamine use leads to long lasting brain and behavioral changes in humans and laboratory rats. These changes have high energy requirements, implicating a role for mitochondria. We explored whether mitochondrial function underpins behaviors that occur in rats months after stopping methamphetamine self-administration. Accordingly, rats self-administered intravenous methamphetamine for 3 h/day for 14 days. The mitochondrial toxin rotenone was administered as (1 mg/kg/day for 6 days) via an osmotic minipump starting at 0, 14 or 28 days of abstinence abstinence. On abstinence day 61, expression of methamphetamine-induced behavioral sensitization was obtained with an acute methamphetamine challenge in rotenone-free rats. Rotenone impeded the expression of sensitization, with the most robust effects obtained with later abstinence exposure. These findings verified that self-titration of moderate methamphetamine doses results in behavioral (and thus brain) changes that can be revealed months after exposure termination, and that the meth-initiated processes progressed during abstinence so that longer abstinence periods were more susceptible to the consequences of exposure to a mitochondrial toxin.
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Affiliation(s)
- I. Daphne Calma
- grid.240684.c0000 0001 0705 3621Departments of Psychiatry and Behavioral Sciences, Rush University Medical Center, Chicago, IL 60612 USA ,grid.240684.c0000 0001 0705 3621Center for Compulsive Behavior and Addiction, Rush University Medical Center, Chicago, IL 60612 USA
| | - Amanda L. Persons
- grid.240684.c0000 0001 0705 3621Departments of Psychiatry and Behavioral Sciences, Rush University Medical Center, Chicago, IL 60612 USA ,grid.240684.c0000 0001 0705 3621Departments of Physician Assistant Studies, Rush University Medical Center, Chicago, IL 60612 USA ,grid.240684.c0000 0001 0705 3621Center for Compulsive Behavior and Addiction, Rush University Medical Center, Chicago, IL 60612 USA
| | - T. Celeste Napier
- grid.240684.c0000 0001 0705 3621Departments of Psychiatry and Behavioral Sciences, Rush University Medical Center, Chicago, IL 60612 USA ,grid.240684.c0000 0001 0705 3621Center for Compulsive Behavior and Addiction, Rush University Medical Center, Chicago, IL 60612 USA ,grid.240684.c0000 0001 0705 3621Department of Psychiatry and Behavioral Sciences, Rush University Medical Center, Suite 424, Cohn Research Building, 1735 W. Harrison Street, Chicago, IL 60610 USA
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Persons AL, Bradaric BD, Kelly LP, Kousik SM, Graves SM, Yamamoto BK, Napier TC. Gut and brain profiles that resemble pre-motor and early-stage Parkinson's disease in methamphetamine self-administering rats. Drug Alcohol Depend 2021; 225:108746. [PMID: 34098381 PMCID: PMC8483557 DOI: 10.1016/j.drugalcdep.2021.108746] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 04/01/2021] [Accepted: 04/01/2021] [Indexed: 12/18/2022]
Abstract
INTRODUCTION Methamphetamine is a potent psychomotor stimulant, and methamphetamine abusers are up to three times more likely to develop Parkinson's disease (PD) later in life. Prodromal PD may involve gut inflammation and the accumulation of toxic proteins that are transported from the enteric nervous system to the central nervous system to mediate, in part, the degeneration of dopaminergic projections. We hypothesized that self-administration of methamphetamine in rats produces a gut and brain profile that mirrors pre-motor and early-stage PD. METHODS Rats self-administered methamphetamine in daily 3 h sessions for two weeks. Motor function was assessed before self-administration, during self-administration and throughout the 56 days of forced abstinence. Assays for pathogenic markers (tyrosine hydroxylase, glial fibrillary acidic protein (GFAP), α-synuclein) were conducted on brain and gut tissue collected at one or 56 days after cessation of methamphetamine self-administration. RESULTS Motor deficits emerged by day 14 of forced abstinence and progressively worsened up to 56 days of forced abstinence. In the pre-motor stage, we observed increased immunoreactivity for GFAP and α-synuclein within the ganglia of the myenteric plexus in the distal colon. Increased α-synuclein was also observed in the substantia nigra pars compacta. At 56 days, GFAP and α-synuclein normalized in the gut, but the accumulation of nigral α-synuclein persisted, and the dorsolateral striatum exhibited a significant loss of tyrosine hydroxylase. CONCLUSION The pre-motor profile is consistent with gut inflammation and gut/brain α-synuclein accumulation associated with prodromal PD and the eventual development of the neurological disease.
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Affiliation(s)
- Amanda L. Persons
- Department of Pharmacology, Rush University Medical Center, Chicago, IL 60612,Department of Psychiatry and Behavioral Sciences, Rush University Medical Center, Chicago, IL 60612,Department of Physician Assistant Studies, Rush University Medical Center, Chicago, IL 60612,Department of Center for Compulsive Behavior and Addiction, Rush University Medical Center, Chicago, IL 60612
| | - Brinda D. Bradaric
- Department of Pharmacology, Rush University Medical Center, Chicago, IL 60612,Department of Health Sciences, Rush University Medical Center, Chicago, IL 60612,Department of Center for Compulsive Behavior and Addiction, Rush University Medical Center, Chicago, IL 60612
| | - Leo P. Kelly
- Department of Pharmacology, Rush University Medical Center, Chicago, IL 60612
| | - Sharanya M. Kousik
- Department of Pharmacology, Rush University Medical Center, Chicago, IL 60612,Department of Center for Compulsive Behavior and Addiction, Rush University Medical Center, Chicago, IL 60612
| | - Steven M. Graves
- Department of Pharmacology, Rush University Medical Center, Chicago, IL 60612,Department of Center for Compulsive Behavior and Addiction, Rush University Medical Center, Chicago, IL 60612
| | - Bryan K. Yamamoto
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN 46202
| | - T. Celeste Napier
- Department of Pharmacology, Rush University Medical Center, Chicago, IL 60612,Department of Psychiatry and Behavioral Sciences, Rush University Medical Center, Chicago, IL 60612,Department of Center for Compulsive Behavior and Addiction, Rush University Medical Center, Chicago, IL 60612
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Ohene-Nyako M, Persons AL, Napier TC. Hippocampal blood-brain barrier of methamphetamine self-administering HIV-1 transgenic rats. Eur J Neurosci 2021; 53:416-429. [PMID: 32725911 PMCID: PMC9949894 DOI: 10.1111/ejn.14925] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 07/19/2020] [Accepted: 07/20/2020] [Indexed: 12/16/2022]
Abstract
Combined antiretroviral therapy for HIV infection reduces plasma viral load and prolongs life. However, the brain is a viral reservoir, and pathologies such as cognitive decline and blood-brain barrier (BBB) disruption persist. Methamphetamine abuse is prevalent among HIV-infected individuals. Methamphetamine and HIV toxic proteins can disrupt the BBB, but it is unclear if there exists a common pathway by which HIV proteins and methamphetamine induce BBB damage. Also unknown are the BBB effects imposed by chronic exposure to HIV proteins in the comorbid context of chronic methamphetamine abuse. To evaluate these scenarios, we trained HIV-1 transgenic (Tg) and non-Tg rats to self-administer methamphetamine using a 21-day paradigm that produced an equivalency dose range at the low end of the amounts self-titrated by humans. Markers of BBB integrity were measured for the hippocampus, a brain region involved in cognitive function. Outcomes revealed that tight junction proteins, claudin-5 and occludin, were reduced in Tg rats independent of methamphetamine, and this co-occurred with increased levels of lipopolysaccharide, albumin (indicating barrier breakdown) and matrix metalloproteinase-9 (MMP-9; indicating barrier matrix disruption); reductions in GFAP (indicating astrocytic dysfunction); and microglial activation (indicating inflammation). Evaluations of markers for two signaling pathways that regulate MMP-9 transcription, NF-κB and ERK/∆FosB revealed an overall genotype effect for NF-κB. Methamphetamine did not alter measurements from Tg rats, but in non-Tg rats, methamphetamine reduced occludin and GFAP, and increased MMP-9 and NF-κB. Study outcomes suggest that BBB dysregulation resulting from chronic exposure to HIV-1 proteins or methamphetamine both involve NF-κB/MMP-9.
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Affiliation(s)
- Michael Ohene-Nyako
- Department of Pharmacology, Rush University, Chicago, IL, USA,Department of Physician Assistant Studies, Rush University, Chicago, IL, USA
| | - Amanda L. Persons
- Department of Physician Assistant Studies, Rush University, Chicago, IL, USA,Department of Psychiatry and Behavioral Sciences, Rush University, Chicago, IL, USA,Center for Compulsive Behavior and Addiction, Rush University, Chicago, IL, USA
| | - T. Celeste Napier
- Department of Pharmacology, Rush University, Chicago, IL, USA,Department of Physician Assistant Studies, Rush University, Chicago, IL, USA,Center for Compulsive Behavior and Addiction, Rush University, Chicago, IL, USA
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Gluncic V, Moric M, Chu Y, Hanko V, Li J, Lukić IK, Lukić A, Edassery SL, Kroin JS, Persons AL, Perry P, Kelly L, Shiveley TJ, Nice K, Napier TC, Kordower JH, Tuman KJ. Corrigendum to: In Utero Exposure to Anesthetics Alters Neuronal Migration Pattern in Developing Cerebral Cortex and Causes Postnatal Behavioral Deficits in Rats. Cereb Cortex 2020; 30:5190. [DOI: 10.1093/cercor/bhz234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 09/05/2019] [Accepted: 09/12/2019] [Indexed: 11/12/2022] Open
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Gluncic V, Moric M, Chu Y, Hanko V, Li J, Lukić IK, Lukić A, Edassery SL, Kroin JS, Persons AL, Perry P, Kelly L, Shiveley TJ, Nice K, Napier CT, Kordower JH, Tuman KJ. In utero Exposure to Anesthetics Alters Neuronal Migration Pattern in Developing Cerebral Cortex and Causes Postnatal Behavioral Deficits in Rats. Cereb Cortex 2019; 29:5285-5301. [DOI: 10.1093/cercor/bhz065] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Abstract
During fetal development, cerebral cortical neurons are generated in the proliferative zone along the ventricles and then migrate to their final positions. To examine the impact of in utero exposure to anesthetics on neuronal migration, we injected pregnant rats with bromodeoxyuridine to label fetal neurons generated at embryonic Day (E) 17 and then randomized these rats to 9 different groups receiving 3 different means of anesthesia (oxygen/control, propofol, isoflurane) for 3 exposure durations (20, 50, 120 min). Histological analysis of brains from 54 pups revealed that significant number of neurons in anesthetized animals failed to acquire their correct cortical position and remained dispersed within inappropriate cortical layers and/or adjacent white matter. Behavioral testing of 86 littermates pointed to abnormalities that correspond to the aberrations in the brain areas that are specifically developing during the E17. In the second set of experiments, fetal brains exposed to isoflurane at E16 had diminished expression of the reelin and glutamic acid decarboxylase 67, proteins critical for neuronal migration. Together, these results call for cautious use of anesthetics during the neuronal migration period in pregnancy and more comprehensive investigation of neurodevelopmental consequences for the fetus and possible consequences later in life.
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Affiliation(s)
- V Gluncic
- Department of Anesthesiology, Rush University Medical Center, Chicago, IL, USA
- Department of Anesthesiology, Advocate Illinois Masonic Medical Center, Chicago IL, USA
| | - M Moric
- Department of Anesthesiology, Rush University Medical Center, Chicago, IL, USA
| | - Y Chu
- Department of Neurological Sciences, Rush Medical College, Rush University Medical Center, Chicago, IL, USA
| | - V Hanko
- Department of Anesthesiology, Rush University Medical Center, Chicago, IL, USA
- Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - J Li
- Department of Anesthesiology, Rush University Medical Center, Chicago, IL, USA
| | - I K Lukić
- Department of Anesthesiology, Rush University Medical Center, Chicago, IL, USA
| | - A Lukić
- Department of Anesthesiology, Rush University Medical Center, Chicago, IL, USA
| | - S L Edassery
- Department of Pharmacology, Rush Medical College, Rush University Medical Center, Chicago, IL, USA
| | - J S Kroin
- Department of Anesthesiology, Rush University Medical Center, Chicago, IL, USA
| | - A L Persons
- Department of Pharmacology, Rush Medical College, Rush University Medical Center, Chicago, IL, USA
- The Center for Compulsive Behavior and Addiction, Rush University Medical Center, Chicago, IL, USA
| | - P Perry
- Department of Anesthesiology, Rush University Medical Center, Chicago, IL, USA
| | - L Kelly
- Department of Neurological Sciences, Rush Medical College, Rush University Medical Center, Chicago, IL, USA
| | - T J Shiveley
- Department of Anesthesiology, Rush University Medical Center, Chicago, IL, USA
| | - K Nice
- Department of Neurological Sciences, Rush Medical College, Rush University Medical Center, Chicago, IL, USA
| | - C T Napier
- Department of Pharmacology, Rush Medical College, Rush University Medical Center, Chicago, IL, USA
- The Center for Compulsive Behavior and Addiction, Rush University Medical Center, Chicago, IL, USA
- Department of Psychiatry, Rush Medical College, Rush University Medical Center, Chicago, IL, USA
| | - J H Kordower
- Department of Neurological Sciences, Rush Medical College, Rush University Medical Center, Chicago, IL, USA
| | - K J Tuman
- Department of Anesthesiology, Rush University Medical Center, Chicago, IL, USA
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Napier TC, Persons AL. Pharmacological insights into impulsive-compulsive spectrum disorders associated with dopaminergic therapy. Eur J Neurosci 2018; 50:2492-2502. [PMID: 30269390 DOI: 10.1111/ejn.14177] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 09/13/2018] [Accepted: 09/14/2018] [Indexed: 12/31/2022]
Abstract
Impulsive-compulsive spectrum disorders are associated with dopamine agonist therapy in some patients. These untoward outcomes occur with direct-acting, full and partial agonists at D2 dopamine family receptors. The disorders typically emerge during chronic treatment, and exhibit common features that are independent of the neurological or psychiatric pathology for which the initial therapy was indicated. It is well-documented that the brain is 'plastic', changing in response to alterations to internal factors (e.g., disease processes), as well as external factors (e.g., therapies). The complexities of these clinical scenarios have eluded a clear depiction of the neurobiology for impulsive-compulsive spectrum disorders and engendered considerable debate regarding the mechanistic underpinnings of the disorders. In this opinion, we use pharmacological concepts related to homeostatic compensation subsequent to chronic receptor activation to provide a unifying construct. This construct helps explain the occurrence of impulsive-compulsive spectrum disorders across disease states, and during therapy with full and partial agonists.
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Affiliation(s)
- T Celeste Napier
- Department of Psychiatry, Rush University Medical Center, Chicago, IL, USA.,Center for Compulsive Behavior and Addiction, Rush University Medical Center, Chicago, IL, USA
| | - Amanda L Persons
- Department of Psychiatry, Rush University Medical Center, Chicago, IL, USA.,Center for Compulsive Behavior and Addiction, Rush University Medical Center, Chicago, IL, USA.,Department of Physician Assistant Studies, Rush University Medical Center, Chicago, IL, USA
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8
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Flack A, Persons AL, Kousik SM, Celeste Napier T, Moszczynska A. Self-administration of methamphetamine alters gut biomarkers of toxicity. Eur J Neurosci 2018; 46:1918-1932. [PMID: 28661099 DOI: 10.1111/ejn.13630] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 06/21/2017] [Accepted: 06/22/2017] [Indexed: 12/13/2022]
Abstract
Methamphetamine (METH) is a highly abused psychostimulant that is associated with an increased risk for developing Parkinson's disease (PD). This enhanced vulnerability likely relates to the toxic effects of METH that overlap with PD pathology, for example, aberrant functioning of α-synuclein and parkin. In PD, peripheral factors are thought to contribute to central nervous system (CNS) degeneration. For example, α-synuclein levels in the enteric nervous system (ENS) are elevated, and this precedes the onset of motor symptoms. It remains unclear whether neurons of the ENS, particularly catecholaminergic neurons, exhibit signs of METH-induced toxicity as seen in the CNS. The aim of this study was to determine whether self-administered METH altered the levels of α-synuclein, parkin, tyrosine hydroxylase (TH), and dopamine-β-hydroxylase (DβH) in the myenteric plexus of the distal colon ENS. Young adult male Sprague-Dawley rats self-administered METH for 3 h per day for 14 days and controls were saline-yoked. Distal colon tissue was collected at 1, 14, or 56 days after the last operant session. Levels of α-synuclein were increased, while levels of parkin, TH, and DβH were decreased in the myenteric plexus in the METH-exposed rats at 1 day following the last operant session and returned to the control levels after 14 or 56 days of forced abstinence. The changes were not confined to neurofilament-positive neurons. These results suggest that colon biomarkers may provide early indications of METH-induced neurotoxicity, particularly in young chronic METH users who may be more susceptible to progression to PD later in life.
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Affiliation(s)
- Amanda Flack
- Department of Pharmaceutical Sciences, Wayne State University, Eugene Applebaum College of Pharmaceutical Sciences, Detroit, MI, 48201, USA
| | - Amanda L Persons
- Center for Compulsive Behavior and Addiction, Rush University Medical Center, Chicago, IL, USA.,Department of Pharmacology, Rush University Medial Center, Chicago, IL, USA
| | - Sharanya M Kousik
- Center for Compulsive Behavior and Addiction, Rush University Medical Center, Chicago, IL, USA.,Department of Pharmacology, Rush University Medial Center, Chicago, IL, USA
| | - T Celeste Napier
- Center for Compulsive Behavior and Addiction, Rush University Medical Center, Chicago, IL, USA.,Department of Pharmacology, Rush University Medial Center, Chicago, IL, USA.,Department of Psychiatry, Rush University Medical Center, Chicago, IL, USA
| | - Anna Moszczynska
- Department of Pharmaceutical Sciences, Wayne State University, Eugene Applebaum College of Pharmaceutical Sciences, Detroit, MI, 48201, USA
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Ohene-Nyako M, Persons AL, Napier TC. Region-specific changes in markers of neuroplasticity revealed in HIV-1 transgenic rats by low-dose methamphetamine. Brain Struct Funct 2018; 223:3503-3513. [PMID: 29931627 DOI: 10.1007/s00429-018-1701-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 06/15/2018] [Indexed: 12/15/2022]
Abstract
Methamphetamine abuse co-occurring with HIV infection presents neuropathology in brain regions that mediate reward and motivation. A neuronal signaling cascade altered acutely by meth and some HIV-1 proteins is the mitogen-activated protein kinase (MAPK) pathway. It remains unknown if chronic co-exposure to meth and HIV-1 proteins converge on MAPK in vivo. To make this determination, we studied young adult Fischer 344 HIV-1 transgenic (Tg) and non-Tg rats that self-administered meth (0.02-0.04 mg/kg/0.05 ml iv infusion, 2 h/day for 21 days) and their saline-yoked controls. One day following the operant task, rats were killed. Brain regions involved in reward-motivation [i.e., nucleus accumbens (NA) and ventral pallidum (VP)], were assayed for a MAPK cascade protein, extracellular signal-regulated kinase (ERK), and a downstream transcription factor, ΔFosB. In the NA, activated (phosphorylated; p) ERK-to-ERK ratio (pERK/ERK) was increased in meth-exposed Tg rats versus saline Tg controls, and versus meth non-Tg rats. ΔFosB was increased in meth Tg rats versus saline and meth non-Tg rats. Assessment of two targets of ΔFosB-regulated transcription revealed (1) increased dopamine D1 receptor (D1R) immunoreactivity in the NA shell of Tg-meth rats versus saline Tg controls, but (2) no changes in the AMPA receptor subunit, GluA2. No changes related to genotype or meth occurred for ERK, ΔFosB or D1R protein in the VP. Results reveal a region-specific activation of ERK, and increases in ΔFosB and D1R expression induced by HIV-1 proteins and meth. Such effects may contribute to the neuronal and behavioral pathology associated with meth/HIV comorbidity.
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Affiliation(s)
- Michael Ohene-Nyako
- Department of Pharmacology, Rush University, Chicago, IL, USA.,Center for Compulsive Behavior and Addiction, Rush University, Chicago, IL, USA
| | - Amanda L Persons
- Department of Physician Assistant Studies, Rush University, Chicago, IL, USA.,Department of Psychiatry, Rush University Medical Center, 1735 W. Harrison Street, Cohn Research Building Suite #424, Chicago, IL, 60612, USA.,Center for Compulsive Behavior and Addiction, Rush University, Chicago, IL, USA
| | - T Celeste Napier
- Department of Psychiatry, Rush University Medical Center, 1735 W. Harrison Street, Cohn Research Building Suite #424, Chicago, IL, 60612, USA. .,Center for Compulsive Behavior and Addiction, Rush University, Chicago, IL, USA.
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10
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Persons AL, Bradaric BD, Dodiya HB, Ohene-Nyako M, Forsyth CB, Keshavarzian A, Shaikh M, Napier TC. Colon dysregulation in methamphetamine self-administering HIV-1 transgenic rats. PLoS One 2018; 13:e0190078. [PMID: 29293553 PMCID: PMC5749763 DOI: 10.1371/journal.pone.0190078] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 12/07/2017] [Indexed: 02/07/2023] Open
Abstract
The integrity and function of the gut is impaired in HIV-infected individuals, and gut pathogenesis may play a role in several HIV-associated disorders. Methamphetamine is a popular illicit drug abused by HIV-infected individuals. However, the effect of methamphetamine on the gut and its potential to exacerbate HIV-associated gut pathology is not known. To shed light on this scenario, we evaluated colon barrier pathology in a rat model of the human comorbid condition. Intestinal barrier integrity and permeability were assessed in drug-naïve Fischer 344 HIV-1 transgenic (Tg) and non-Tg rats, and in Tg and non-Tg rats instrumented with jugular cannulae trained to self-administer methamphetamine or serving as saline-yoked controls. Intestinal permeability was determined by measuring the urine content of orally gavaged sugars. Intestinal barrier integrity was evaluated by immunoblotting or immunofluorescence of colon claudin-1 and zonula occludens-1 (ZO-1), two major tight junction proteins that regulate gut epithelial paracellular permeability. Both non-Tg and Tg rats self-administered moderate amounts of methamphetamine. These amounts were sufficient to increase colon permeability, reduce protein level of claudin-1, and reduce claudin-1 and ZO-1 immunofluorescence in Tg rats relative to non-Tg rats. Methamphetamine decreased tight junction immunofluorescence in non-Tg rats, with a similar, but non-significant trend observed in Tg rats. However, the effect of methamphetamine on tight junction proteins was subthreshold to gut leakiness. These findings reveal that both HIV-1 proteins and methamphetamine alter colon barrier integrity, and indicate that the gut may be a pathogenic site for these insults.
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Affiliation(s)
- Amanda L. Persons
- Department of Psychiatry, Rush University Medical Center, Chicago, IL, United States of America
- Department of Physician Assistant Studies, Rush University Medical Center, Chicago, IL, United States of America
- Center for Compulsive Behavior and Addiction, Rush University Medical Center, Chicago, IL, United States of America
- * E-mail:
| | - Brinda D. Bradaric
- Center for Compulsive Behavior and Addiction, Rush University Medical Center, Chicago, IL, United States of America
- Department of Health Sciences, Rush University Medical Center, Chicago, IL, United States of America
| | - Hemraj B. Dodiya
- Department of Pharmacology, Rush University Medical Center, Chicago, IL, United States of America
| | - Michael Ohene-Nyako
- Center for Compulsive Behavior and Addiction, Rush University Medical Center, Chicago, IL, United States of America
- Department of Pharmacology, Rush University Medical Center, Chicago, IL, United States of America
| | - Christopher B. Forsyth
- Department of Internal Medicine, Division of Digestive Diseases and Nutrition, Rush University Medical Center, Chicago, IL, United States of America
| | - Ali Keshavarzian
- Center for Compulsive Behavior and Addiction, Rush University Medical Center, Chicago, IL, United States of America
- Department of Internal Medicine, Division of Digestive Diseases and Nutrition, Rush University Medical Center, Chicago, IL, United States of America
| | - Maliha Shaikh
- Department of Internal Medicine, Division of Digestive Diseases and Nutrition, Rush University Medical Center, Chicago, IL, United States of America
| | - T. Celeste Napier
- Department of Psychiatry, Rush University Medical Center, Chicago, IL, United States of America
- Center for Compulsive Behavior and Addiction, Rush University Medical Center, Chicago, IL, United States of America
- Department of Pharmacology, Rush University Medical Center, Chicago, IL, United States of America
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11
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Persons AL, Tedford SE, Napier TC. Mirtazapine and ketanserin alter preference for gambling-like schedules of reinforcement in rats. Prog Neuropsychopharmacol Biol Psychiatry 2017; 77:178-184. [PMID: 28412411 PMCID: PMC5656013 DOI: 10.1016/j.pnpbp.2017.03.027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 03/15/2017] [Accepted: 03/21/2017] [Indexed: 12/15/2022]
Abstract
Drug and behavioral addictions have overlapping features, e.g., both manifest preference for larger, albeit costlier, reinforcement options in cost/benefit decision-making tasks. Our prior work revealed that the mixed-function serotonergic compound, mirtazapine, attenuates behaviors by rats motivated by abused drugs. To extend this work to behavioral addictions, here we determined if mirtazapine and/or ketanserin, another mixed-function serotonin-acting compound, can alter decision-making in rats that is independent of drug (or food)-motivated reward. Accordingly, we developed a novel variable-ratio task in rats wherein intracranial self-stimulation was used as the positive reinforcer. Using lever pressing for various levels of brain stimulation, the operant task provided choices between a small brain stimulation current delivered on a fixed-ratio schedule (i.e., a predictable reward) and a large brain stimulation delivered following an unpredictable number of responses (i.e., a variable-ratio schedule). This task allowed for demonstration of individualized preference and detection of shifts in motivational influences during a pharmacological treatment. Once baseline preference was established, we determined that pretreatment with mirtazapine or ketanserin significantly decreased preference for the large reinforcer presented after gambling-like schedules of reinforcement. When the rats were tested the next day without drug, preference for the unpredictable large reinforcer option was restored. These data demonstrate that mirtazapine and ketanserin can reduce preference for larger, costlier reinforcement options, and illustrate the potential for these drugs to alter behavior.
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Affiliation(s)
- Amanda L. Persons
- Dept. of Pharmacology, Rush University Medical Center, Chicago, IL,Dept. of Physician Assistant Studies, Rush University Medical Center, Chicago, IL,Center for Compulsive Behavior and Addiction, Rush University Medical Center, Chicago, IL
| | - Stephanie E. Tedford
- Dept. of Pharmacology, Rush University Medical Center, Chicago, IL,Center for Compulsive Behavior and Addiction, Rush University Medical Center, Chicago, IL
| | - T. Celeste Napier
- Dept. of Pharmacology, Rush University Medical Center, Chicago, IL,Dept. of Psychiatry, Rush University Medical Center, Chicago, IL,Center for Compulsive Behavior and Addiction, Rush University Medical Center, Chicago, IL
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12
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Holtz NA, Tedford SE, Persons AL, Grasso SA, Napier TC. Pharmacologically distinct pramipexole-mediated akinesia vs. risk-taking in a rat model of Parkinson's disease. Prog Neuropsychopharmacol Biol Psychiatry 2016; 70:77-84. [PMID: 27216282 PMCID: PMC5410378 DOI: 10.1016/j.pnpbp.2016.05.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Revised: 05/17/2016] [Accepted: 05/18/2016] [Indexed: 02/08/2023]
Abstract
Pramipexole and ropinirole are dopamine agonists that are efficacious in treating motor disturbances of neuropathologies, e.g., Parkinson's disease and restless legs syndrome. A significant portion of treated patients develop impulsive/compulsive behaviors. Current treatment is dose reduction or switching to an alternative dopamine replacement, both of which can undermine the motor benefits. Needed is a preclinical model that can assist in identifying adjunct treatments to dopamine agonist therapy that reduce impulsive/compulsive behaviors without interfering with motor benefits of the dopamine agonist. Toward that objective, the current study implemented a rat model of Parkinson's disease to behaviorally profile chronically administered pramipexole. This was accomplished with male Sprague-Dawley rats wherein (i) 6-hydroxydopamine-induced lesions of the dorsolateral striatum produced Parkinson's disease-like akinesia, measured in the forelimbs, (ii) intracranial self-stimulation-mediated probability discounting indicated impulsivity/risk-taking, and (iii) two doses of pramipexole were continuously administered for 14-28days via osmotic minipumps to mirror the chronic, stable exposure achieved with extended release formulations. The atypical antidepressant, mirtazapine, is known to reduce behaviors associated with drug addiction in rats; thus, we demonstrated model utility here by determining the effects of mirtazapine on pramipexole-induced motor improvements versus probability discounting. We observed that forelimb akinesia subsequent to striatal lesions was attenuated by both pramipexole doses tested (0.3 and 1.2mg/kg/day) within 4h of pump implant dispensing 0.3mg/kg/day and 1h by 1.2mg/kg/day. By contrast, 12-14days of infusion with 0.3mg/kg/day did not alter discounting, but increases were obtained with 1.2mg/kg/day pramipexole, with 67% of 1.2mg/kg/day-treated rats meeting categorical criteria for 'high risk-taking'. Insertion of a second minipump delivering mirtazapine did not alter motor function during 14days of co-administration with pramipexole, but was sufficient to attenuate risk-taking. These outcomes revealed distinct probability discounting and anti-akinesia profiles for pramipexole, indicating that pharmacotherapy, (e.g., mirtazapine treatments), can be developed that reduce risk-taking while leaving motor benefits intact.
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Affiliation(s)
- Nathan A. Holtz
- Dept. of Pharmacology, Rush University Medical Center, Chicago, IL USA,Center for Compulsive Behavior and Addiction, Rush University Medical Center, Chicago, IL USA
| | - Stephanie E. Tedford
- Dept. of Pharmacology, Rush University Medical Center, Chicago, IL USA,Center for Compulsive Behavior and Addiction, Rush University Medical Center, Chicago, IL USA
| | - Amanda L. Persons
- Dept. of Pharmacology, Rush University Medical Center, Chicago, IL USA,Center for Compulsive Behavior and Addiction, Rush University Medical Center, Chicago, IL USA
| | - Salvatore A. Grasso
- Dept. of Pharmacology, Rush University Medical Center, Chicago, IL USA,Center for Compulsive Behavior and Addiction, Rush University Medical Center, Chicago, IL USA
| | - T. Celeste Napier
- Dept. of Pharmacology, Rush University Medical Center, Chicago, IL USA,Dept. of Psychiatry, Rush University Medical Center, Chicago, IL USA,Center for Compulsive Behavior and Addiction, Rush University Medical Center, Chicago, IL USA
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13
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Wayman WN, Chen L, Persons AL, Napier TC. Cortical consequences of HIV-1 Tat exposure in rats are enhanced by chronic cocaine. Curr HIV Res 2015; 13:80-7. [PMID: 25760043 DOI: 10.2174/0929867322666150311164504] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Revised: 01/22/2015] [Accepted: 02/09/2015] [Indexed: 01/25/2023]
Abstract
The life span of individuals that are sero-positive for human immunodeficiency virus (HIV) has greatly improved; however, complications involving the central nervous system (CNS) remain a concern. While HIV does not directly infect neurons, the proteins produced by the virus, including HIV transactivator of transcription (Tat), are released from infected glia; these proteins can be neurotoxic. This neurotoxicity is thought to mediate the pathology underlying HIVassociated neurological impairments. Cocaine abuse is common among HIV infected individuals, and this abuse augments HIV-associated neurological deficits. The brain regions and pathophysiological mechanisms that are dysregulated by both chronic cocaine and Tat are the focus of the current review.
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Affiliation(s)
- Wesley N Wayman
- Department of Pharmacology, Rush University Medical Center, 1735 W. Harrison Street, Cohn Research Building, Rm. 463, Chicago, IL 60612, USA.
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14
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Tedford SE, Persons AL, Napier TC. Dopaminergic lesions of the dorsolateral striatum in rats increase delay discounting in an impulsive choice task. PLoS One 2015; 10:e0122063. [PMID: 25927685 PMCID: PMC4415807 DOI: 10.1371/journal.pone.0122063] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 02/16/2015] [Indexed: 01/01/2023] Open
Abstract
Dysregulated dopamine transmission in striatal circuitry is associated with impulsivity. The current study evaluated the influence of dopaminergic inputs to the dorsolateral striatum on impulsive choice, one aspect of impulsive behavior. We implemented an operant task that measures impulsive choice in rats via delay discounting wherein intracranial self-stimulation (ICSS) was used as the positive reinforcer. To do so, rats were anesthetized to allow implanting of a stimulating electrode within the lateral hypothalamus of one hemisphere and bilateral dorsal striatal injections of the dopaminergic toxin, 6-OHDA (lesioned) or its vehicle (sham). Following recovery, rats were trained in a delay discounting task wherein they selected between a small ICSS current presented immediately after lever pressing, and a large ICSS current presented following a 0 to 15s delay upon pressing the alternate lever. Task acquisition and reinforcer discrimination were similar for lesioned and sham rats. All rats exhibited an initial preference for the large reinforcer, and as the delay was increased, preference for the large reinforcer was decreased indicating that the subjective value of the large reinforcer was discounted as a function of delay time. However, this discounting effect was significantly enhanced in lesioned rats for the longer delays. These data reveal a contribution of dopaminergic inputs to the dorsolateral striatum on impulsive choice behavior, and provide new insights into neural substrates underlying discounting behaviors.
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Affiliation(s)
- Stephanie E Tedford
- Department of Pharmacology, Rush University, Chicago, Illinois, United States of America; Center for Compulsive Behavior and Addiction, Rush University, Chicago, Illinois, United States of America
| | - Amanda L Persons
- Department of Pharmacology, Rush University, Chicago, Illinois, United States of America; Center for Compulsive Behavior and Addiction, Rush University, Chicago, Illinois, United States of America
| | - T Celeste Napier
- Department of Pharmacology, Rush University, Chicago, Illinois, United States of America; Department of Psychiatry, Rush University, Chicago, Illinois, United States of America; Center for Compulsive Behavior and Addiction, Rush University, Chicago, Illinois, United States of America
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15
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Tedford SE, Holtz NA, Persons AL, Napier TC. A new approach to assess gambling-like behavior in laboratory rats: using intracranial self-stimulation as a positive reinforcer. Front Behav Neurosci 2014; 8:215. [PMID: 24966822 PMCID: PMC4052818 DOI: 10.3389/fnbeh.2014.00215] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 05/27/2014] [Indexed: 11/17/2022] Open
Abstract
Pathological gambling is one manifestation of impulse control disorders. The biological underpinnings of these disorders remain elusive and treatment is far from ideal. Animal models of impulse control disorders are a critical research tool for understanding this condition and for medication development. Modeling such complex behaviors is daunting, but by its deconstruction, scientists have recapitulated in animals critical aspects of gambling. One aspect of gambling is cost/benefit decision-making wherein one weighs the anticipated costs and expected benefits of a course of action. Risk/reward, delay-based and effort-based decision-making all represent cost/benefit choices. These features are studied in humans and have been translated to animal protocols to measure decision-making processes. Traditionally, the positive reinforcer used in animal studies is food. Here, we describe how intracranial self-stimulation can be used for cost/benefit decision-making tasks and overview our recent studies showing how pharmacological therapies alter these behaviors in laboratory rats. We propose that these models may have value in screening new compounds for the ability to promote and prevent aspects of gambling behavior.
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Affiliation(s)
- Stephanie E Tedford
- Department of Pharmacology, Center for Compulsive Behavior and Addiction, Rush University Medical Center Chicago, IL, USA ; Department of Pharmacology, Rush University Medical Center Chicago, IL, USA
| | - Nathan A Holtz
- Department of Pharmacology, Center for Compulsive Behavior and Addiction, Rush University Medical Center Chicago, IL, USA ; Department of Pharmacology, Rush University Medical Center Chicago, IL, USA
| | - Amanda L Persons
- Department of Pharmacology, Center for Compulsive Behavior and Addiction, Rush University Medical Center Chicago, IL, USA ; Department of Pharmacology, Rush University Medical Center Chicago, IL, USA
| | - T Celeste Napier
- Department of Pharmacology, Center for Compulsive Behavior and Addiction, Rush University Medical Center Chicago, IL, USA ; Department of Pharmacology, Rush University Medical Center Chicago, IL, USA ; Department of Psychiatry, Rush University Medical Center Chicago, IL, USA
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16
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Herrold AA, Persons AL, Napier TC. Cellular distribution of AMPA receptor subunits and mGlu5 following acute and repeated administration of morphine or methamphetamine. J Neurochem 2013; 126:503-17. [PMID: 23711322 DOI: 10.1111/jnc.12323] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2013] [Revised: 05/09/2013] [Accepted: 05/14/2013] [Indexed: 01/14/2023]
Abstract
Ionotropic AMPA receptors (AMPAR) and metabotropic glutamate group I subtype 5 receptors (mGlu5) mediate neuronal and behavioral effects of abused drugs. mGlu5 stimulation increases expression of striatal-enriched tyrosine phosphatase isoform 61 (STEP61 ) which internalizes AMPARs. We determined the rat brain profile of these proteins using two different classes of abused drugs, opiates, and stimulants. STEP61 levels, and cellular distribution/expression of AMPAR subunits (GluA1, GluA2) and mGlu5, were evaluated via a protein cross-linking assay in medial prefrontal cortex (mPFC), nucleus accumbens (NAc), and ventral pallidum (VP) harvested 1 day after acute, or fourteen days after repeated morphine (8 mg/kg) or methamphetamine (1 mg/kg) (treatments producing behavioral sensitization). Acute morphine decreased GluA1 and GluA2 surface expression in mPFC and GluA1 in NAc. Fourteen days after repeated morphine or methamphetamine, mGlu5 surface expression increased in VP. In mPFC, mGlu5 were unaltered; however, after methamphetamine, STEP61 levels decreased and GluA2 surface expression increased. Pre-treatment with a mGlu5-selective negative allosteric modulator, blocked methamphetamine-induced behavioral sensitization and changes in mPFC GluA2 and STEP61 . These data reveal (i) region-specific distinctions in glutamate receptor trafficking between acute and repeated treatments of morphine and methamphetamine, and (ii) that mGlu5 is necessary for methamphetamine-induced alterations in mPFC GluA2 and STEP61 .
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Affiliation(s)
- Amy A Herrold
- Laboratory of Origin, Department of Pharmacology, Center for Compulsive Behavior and Addiction, Rush University Medical Center, Chicago, Illinois 60612, USA
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Abstract
HIV-1 proteins, including the transactivator of transcription (Tat), are believed to be involved in HIV-associated neurocognitive disorders by disrupting Ca²⁺ homeostasis, which leads to progressive dysregulation, damage, or death of neurons in the brain. We have found previously that bath-applied Tat abnormally increased Ca²⁺ influx through overactivated, voltage-sensitive L-type Ca²⁺ channels in pyramidal neurons within the rat medial prefrontal cortex (mPFC). However, it is unknown whether the Tat-induced Ca²⁺ dysregulation was mediated by increased activity and/or the number of the L-channels. This study tested the hypothesis that transient/early exposure to Tat in vivo promoted enduring L-channel dysregulation in the mPFC without neuron loss. Accordingly, rats were administered a single intracerebroventricular injection of recombinant Tat (80 μg/20 μl; diluted by cerebrospinal fluids to pathophysiological concentrations) or vehicle. Rats were killed 14 days after injection for immunohistochemical assessments of the mPFC, motor cortex, caudate-putamen, and nucleus accumbens. Stereological estimates for positively stained cells indicated a significant increase in the number of cells expressing the pore-forming Ca(v)1.2-α1c subunit of L-channels in the mPFC compared with other regions in Tat-treated or vehicle-treated rat brains. Optical density measurements showed a Tat-induced increase in glial fibrillary acidic protein expression, indicating astrogliosis in the cortical regions. There was no significant loss of neurons in any brain region investigated. These findings indicate that transient Tat exposure in vivo induced enduring L-channel dysregulation and astrogliosis in the mPFC without neuron loss. Such maladaptations may contribute toward dysregulated Ca²⁺ homeostasis and neuropathology in the PFC in the early stages of HIV infection.
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Affiliation(s)
- Wesley N Wayman
- Rush University Medical Center, Chicago, Illinois 60612, USA.
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Graves SM, Persons AL, Riddle JL, Napier TC. The atypical antidepressant mirtazapine attenuates expression of morphine-induced place preference and motor sensitization. Brain Res 2012; 1472:45-53. [PMID: 22820297 DOI: 10.1016/j.brainres.2012.07.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Revised: 06/24/2012] [Accepted: 07/03/2012] [Indexed: 12/27/2022]
Abstract
Opioid abuse and dependence remains prevalent despite having multiple FDA-approved medications to help maintain abstinence. Mirtazapine is an atypical antidepressant receiving attention for substance abuse pharmacotherapy, and its action includes alterations in monoaminergic transmission. As monoamines are indirectly altered by opioids, the current investigation assessed the ability of mirtazapine to ameliorate morphine-induced behaviors. Conditioned place preference (CPP) is a behavioral assay wherein a rewarding drug is paired with a distinct environmental context resulting in reward-related salience of cues through learning-related neuronal plasticity. A second behavioral assay involved motor sensitization (MSn), wherein repeated administration results in an enhanced motoric response to an acute challenge, also reflecting neuronal plasticity. Attenuation of CPP and/or MSn provides two behavioral measures to suggest therapeutic potential for addiction therapy, and the present study evaluated the effectiveness of mirtazapine to reduce both behaviors. To do so, morphine-induced CPP was established using an eight day conditioning paradigm, and expression of CPP was tested on day 10 following a 24h or 30min mirtazapine pretreatment. To determine if mirtazapine altered the expression of MSn, on day 11, rats received a pretreatment of mirtazapine, followed 30min later by a challenge injection of morphine. Pretreatment with mirtazapine 24h prior to the CPP test had no effect on CPP expression. In contrast, a 30min pretreatment of mirtazapine attenuated the expression of both CPP and MSn. Collectively, these results indicate that mirtazapine may help to maintain abstinence in opioid dependent patients.
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Affiliation(s)
- Steven M Graves
- Department of Pharmacology, Center for Compulsive Behaviors and Addiction, Rush University Medical Center, Chicago, IL 60657, USA
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