1
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Boateng CA, Nilson AN, Placide R, Pham ML, Jakobs FM, Boldizsar N, McIntosh S, Stallings LS, Korankyi IV, Kelshikar S, Shah N, Panasis D, Muccilli A, Ladik M, Maslonka B, McBride C, Sanchez MX, Akca E, Alkhatib M, Saez J, Nguyen C, Kurtyan E, DePierro J, Crowthers R, Brunt D, Bonifazi A, Newman AH, Rais R, Slusher BS, Free RB, Sibley DR, Stewart KD, Wu C, Hemby SE, Keck TM. Pharmacology and Therapeutic Potential of Benzothiazole Analogues for Cocaine Use Disorder. J Med Chem 2023; 66:12141-12162. [PMID: 37646374 PMCID: PMC10510399 DOI: 10.1021/acs.jmedchem.3c00734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Indexed: 09/01/2023]
Abstract
Pharmacological targeting of the dopamine D4 receptor (D4R)─expressed in brain regions that control cognition, attention, and decision-making─could be useful for several neuropsychiatric disorders including substance use disorders (SUDs). This study focused on the synthesis and evaluation of a novel series of benzothiazole analogues designed to target D4R. We identified several compounds with high D4R binding affinity (Ki ≤ 6.9 nM) and >91-fold selectivity over other D2-like receptors (D2R, D3R) with diverse partial agonist and antagonist profiles. Novel analogue 16f is a potent low-efficacy D4R partial agonist, metabolically stable in rat and human liver microsomes, and has excellent brain penetration in rats (AUCbrain/plasma > 3). 16f (5-30 mg/kg, i.p.) dose-dependently decreased iv cocaine self-administration in rats, consistent with previous results produced by D4R-selective antagonists. Off-target antagonism of 5-HT2A or 5-HT2B may also contribute to these effects. Results with 16f support further efforts to target D4R in SUD treatment.
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Affiliation(s)
- Comfort A. Boateng
- Department
of Basic Pharmaceutical Sciences, Fred Wilson School of Pharmacy, High Point University, One University Parkway, High Point, North Carolina 27268, United States
| | - Ashley N. Nilson
- Molecular
Neuropharmacology Section, National Institute of Neurological Disorders
and Stroke-Intramural Research Program, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Rebekah Placide
- Department
of Basic Pharmaceutical Sciences, Fred Wilson School of Pharmacy, High Point University, One University Parkway, High Point, North Carolina 27268, United States
| | - Mimi L. Pham
- Department
of Basic Pharmaceutical Sciences, Fred Wilson School of Pharmacy, High Point University, One University Parkway, High Point, North Carolina 27268, United States
| | - Franziska M. Jakobs
- Department
of Basic Pharmaceutical Sciences, Fred Wilson School of Pharmacy, High Point University, One University Parkway, High Point, North Carolina 27268, United States
| | - Noelia Boldizsar
- Molecular
Neuropharmacology Section, National Institute of Neurological Disorders
and Stroke-Intramural Research Program, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Scot McIntosh
- Department
of Basic Pharmaceutical Sciences, Fred Wilson School of Pharmacy, High Point University, One University Parkway, High Point, North Carolina 27268, United States
| | - Leia S. Stallings
- Department
of Basic Pharmaceutical Sciences, Fred Wilson School of Pharmacy, High Point University, One University Parkway, High Point, North Carolina 27268, United States
| | - Ivana V. Korankyi
- Department
of Basic Pharmaceutical Sciences, Fred Wilson School of Pharmacy, High Point University, One University Parkway, High Point, North Carolina 27268, United States
| | - Shreya Kelshikar
- Department
of Chemistry & Biochemistry, Department of Biological & Biomedical
Sciences, College of Science and Mathematics, Rowan University, 201 Mullica Hill Road, Glassboro, New Jersey 08028, United States
| | - Nisha Shah
- Department
of Chemistry & Biochemistry, Department of Biological & Biomedical
Sciences, College of Science and Mathematics, Rowan University, 201 Mullica Hill Road, Glassboro, New Jersey 08028, United States
| | - Diandra Panasis
- Department
of Chemistry & Biochemistry, Department of Biological & Biomedical
Sciences, College of Science and Mathematics, Rowan University, 201 Mullica Hill Road, Glassboro, New Jersey 08028, United States
| | - Abigail Muccilli
- Department
of Chemistry & Biochemistry, Department of Biological & Biomedical
Sciences, College of Science and Mathematics, Rowan University, 201 Mullica Hill Road, Glassboro, New Jersey 08028, United States
| | - Maria Ladik
- Department
of Chemistry & Biochemistry, Department of Biological & Biomedical
Sciences, College of Science and Mathematics, Rowan University, 201 Mullica Hill Road, Glassboro, New Jersey 08028, United States
| | - Brianna Maslonka
- Department
of Chemistry & Biochemistry, Department of Biological & Biomedical
Sciences, College of Science and Mathematics, Rowan University, 201 Mullica Hill Road, Glassboro, New Jersey 08028, United States
| | - Connor McBride
- Department
of Chemistry & Biochemistry, Department of Biological & Biomedical
Sciences, College of Science and Mathematics, Rowan University, 201 Mullica Hill Road, Glassboro, New Jersey 08028, United States
| | - Moises Ximello Sanchez
- Department
of Chemistry & Biochemistry, Department of Biological & Biomedical
Sciences, College of Science and Mathematics, Rowan University, 201 Mullica Hill Road, Glassboro, New Jersey 08028, United States
| | - Ebrar Akca
- Department
of Chemistry & Biochemistry, Department of Biological & Biomedical
Sciences, College of Science and Mathematics, Rowan University, 201 Mullica Hill Road, Glassboro, New Jersey 08028, United States
| | - Mohammad Alkhatib
- Department
of Chemistry & Biochemistry, Department of Biological & Biomedical
Sciences, College of Science and Mathematics, Rowan University, 201 Mullica Hill Road, Glassboro, New Jersey 08028, United States
| | - Julianna Saez
- Department
of Chemistry & Biochemistry, Department of Biological & Biomedical
Sciences, College of Science and Mathematics, Rowan University, 201 Mullica Hill Road, Glassboro, New Jersey 08028, United States
| | - Catherine Nguyen
- Department
of Chemistry & Biochemistry, Department of Biological & Biomedical
Sciences, College of Science and Mathematics, Rowan University, 201 Mullica Hill Road, Glassboro, New Jersey 08028, United States
| | - Emily Kurtyan
- Department
of Chemistry & Biochemistry, Department of Biological & Biomedical
Sciences, College of Science and Mathematics, Rowan University, 201 Mullica Hill Road, Glassboro, New Jersey 08028, United States
| | - Jacquelyn DePierro
- Department
of Chemistry & Biochemistry, Department of Biological & Biomedical
Sciences, College of Science and Mathematics, Rowan University, 201 Mullica Hill Road, Glassboro, New Jersey 08028, United States
| | - Raymond Crowthers
- Department
of Chemistry & Biochemistry, Department of Biological & Biomedical
Sciences, College of Science and Mathematics, Rowan University, 201 Mullica Hill Road, Glassboro, New Jersey 08028, United States
| | - Dylan Brunt
- Department
of Chemistry & Biochemistry, Department of Biological & Biomedical
Sciences, College of Science and Mathematics, Rowan University, 201 Mullica Hill Road, Glassboro, New Jersey 08028, United States
| | - Alessandro Bonifazi
- Medicinal
Chemistry Section, Molecular Targets and Medications Discovery Branch,
National Institute on Drug Abuse-Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| | - Amy Hauck Newman
- Medicinal
Chemistry Section, Molecular Targets and Medications Discovery Branch,
National Institute on Drug Abuse-Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| | - Rana Rais
- Department
of Neurology, Johns Hopkins Drug Discovery, The Johns Hopkins University School of Medicine, 855 North Wolfe Street, Baltimore, Maryland 21205, United States
| | - Barbara S. Slusher
- Department
of Neurology, Johns Hopkins Drug Discovery, The Johns Hopkins University School of Medicine, 855 North Wolfe Street, Baltimore, Maryland 21205, United States
| | - R. Benjamin Free
- Molecular
Neuropharmacology Section, National Institute of Neurological Disorders
and Stroke-Intramural Research Program, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - David R. Sibley
- Molecular
Neuropharmacology Section, National Institute of Neurological Disorders
and Stroke-Intramural Research Program, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Kent D. Stewart
- Department
of Basic Pharmaceutical Sciences, Fred Wilson School of Pharmacy, High Point University, One University Parkway, High Point, North Carolina 27268, United States
| | - Chun Wu
- Department
of Chemistry & Biochemistry, Department of Biological & Biomedical
Sciences, College of Science and Mathematics, Rowan University, 201 Mullica Hill Road, Glassboro, New Jersey 08028, United States
| | - Scott E. Hemby
- Department
of Basic Pharmaceutical Sciences, Fred Wilson School of Pharmacy, High Point University, One University Parkway, High Point, North Carolina 27268, United States
| | - Thomas M. Keck
- Department
of Chemistry & Biochemistry, Department of Biological & Biomedical
Sciences, College of Science and Mathematics, Rowan University, 201 Mullica Hill Road, Glassboro, New Jersey 08028, United States
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2
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Hemby SE, McIntosh S. Chronic haloperidol administration downregulates select BDNF transcript and protein levels in the dorsolateral prefrontal cortex of rhesus monkeys. Front Psychiatry 2023; 14:1054506. [PMID: 36816400 PMCID: PMC9932326 DOI: 10.3389/fpsyt.2023.1054506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 01/16/2023] [Indexed: 02/05/2023] Open
Abstract
Post-mortem studies in the prefrontal cortex and hippocampal formation from schizophrenia patients have revealed significant disruptions in the expression molecules associated with cytoarchitecture, synaptic structure, function, and plasticity, known to be regulated in part by brain derived neurotrophic factor (BDNF). Interestingly, several studies using postmortem brain tissue from individuals diagnosed with schizophrenia have revealed a significant reduction in BDNF mRNA and protein levels in the dorsolateral prefrontal cortex (DLPFC), hippocampus and related areas; however, differentiating the effects of illness from antipsychotic history has remained difficult. We hypothesized that chronic antipsychotic treatment may contribute to the altered BDNF mRNA and protein expression observed in post-mortem brains of individuals diagnosed with schizophrenia. To address the influence of antipsychotic administration on BDNF expression in the primate brain, rhesus monkeys orally administered haloperidol, clozapine, or vehicle twice daily for 180 days. We found BDNF splice variants 4 and 5 in the DLPFC and variant 2 in the EC were significantly down-regulated following chronic administration of haloperidol. In addition, proBDNF and mature BDNF expression in the DLPFC, but not the EC, were significantly reduced. Based on the known regulation of BDNF expression by BDNF-AS, we assessed the expression of this lncRNA and found expression was significantly upregulated in the DLPFC, but not EC. The results of the present study provide evidence of haloperidol-induced regulation of BDNF mRNA and protein expression in the DLFPC and suggest an important role for BDNF-AS in this regulation. Given the role of BDNF in synaptic plasticity, neuronal survival and maintenance, aberrant expression induced by haloperidol likely has significant ramifications for neuronal populations and circuits in primate cortex.
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Affiliation(s)
- Scott E Hemby
- Department of Basic Pharmaceutical Sciences, Fred Wilson School of Pharmacy, High Point University, High Point, NC, United States
| | - Scot McIntosh
- Department of Basic Pharmaceutical Sciences, Fred Wilson School of Pharmacy, High Point University, High Point, NC, United States
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3
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Hemby SE, McIntosh S, Graf TN, Rangel‐Grimaldo M, Flores‐Bocanegra L, Coover R, Oberlies N. Pharmacological characterization of kratom alkaloids at opiate receptors: binding affinities,
in vitro
and
in vivo
functional assessments. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.r2549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Scott E. Hemby
- Basic Pharmaceutical SciencesHigh Point UniversityHigh PointNC
| | - Scot McIntosh
- Basic Pharmaceutical SciencesHigh Point UniversityHigh PointNC
| | - Tyler N. Graf
- Chemistry and BiochemistryUniversity of North Carolina at GreensboroGreensboroNC
| | | | | | - Robert Coover
- Basic Pharmaceutical SciencesHigh Point UniversityHigh PointNC
| | - Nicholas Oberlies
- Chemistry and BiochemistryUniversity of North Carolina at GreensboroGreensboroNC
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4
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Al Subeh ZY, Raja HA, Burdette JE, Falkinham JO, Hemby SE, Oberlies NH. Three diketomorpholines from a Penicillium sp. (strain G1071). Phytochemistry 2021; 189:112830. [PMID: 34157637 PMCID: PMC8292221 DOI: 10.1016/j.phytochem.2021.112830] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 06/03/2021] [Accepted: 06/04/2021] [Indexed: 06/13/2023]
Abstract
Three previously undescribed diketomorpholine natural products, along with the known phenalenones, herqueinone and norherqueinone, were isolated from the mycoparasitic fungal strain G1071, which was identified as a Penicillium sp. in the section Sclerotiora. The structures were established by analyzing NMR data and mass spectrometry fragmentation patterns. The absolute configurations of deacetyl-javanicunine A, javanicunine C, and javanicunine D, were assigned by examining ECD spectra and Marfey's analysis. The structural diversity generated by this fungal strain was interesting, as only a few diketomorpholines (~17) have been reported from nature.
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Affiliation(s)
- Zeinab Y Al Subeh
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC, United States
| | - Huzefa A Raja
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC, United States
| | - Joanna E Burdette
- Department of Pharmaceutical Sciences, University of Illinois at Chicago, Chicago, IL, United States
| | - Joseph O Falkinham
- Department of Biological Sciences, Virginia Tech Center for Drug Discovery, Virginia Tech, Blacksburg, VA, United States
| | - Scott E Hemby
- Department of Basic Pharmaceutical Sciences, Fred Wilson School of Pharmacy, High Point University, High Point, NC, United States
| | - Nicholas H Oberlies
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC, United States.
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5
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Todd DA, Kellogg JJ, Wallace ED, Khin M, Flores-Bocanegra L, Tanna RS, McIntosh S, Raja HA, Graf TN, Hemby SE, Paine MF, Oberlies NH, Cech NB. Chemical composition and biological effects of kratom (Mitragyna speciosa): In vitro studies with implications for efficacy and drug interactions. Sci Rep 2020; 10:19158. [PMID: 33154449 PMCID: PMC7645423 DOI: 10.1038/s41598-020-76119-w] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 10/22/2020] [Indexed: 01/24/2023] Open
Abstract
The safety and efficacy of kratom (Mitragyna speciosa) for treatment of pain is highly controversial. Kratom produces more than 40 structurally related alkaloids, but most studies have focused on just two of these, mitragynine and 7-hydroxymitragynine. Here, we profiled 53 commercial kratom products using untargeted LC-MS metabolomics, revealing two distinct chemotypes that contain different levels of the alkaloid speciofoline. Both chemotypes were confirmed with DNA barcoding to be M. speciosa. To evaluate the biological relevance of variable speciofoline levels in kratom, we compared the opioid receptor binding activity of speciofoline, mitragynine, and 7-hydroxymitragynine. Mitragynine and 7-hydroxymitragynine function as partial agonists of the human µ-opioid receptor, while speciofoline does not exhibit measurable binding affinity at the µ-, δ- or ƙ-opioid receptors. Importantly, mitragynine and 7-hydroxymitragynine demonstrate functional selectivity for G-protein signaling, with no measurable recruitment of β-arrestin. Overall, the study demonstrates the unique binding and functional profiles of the kratom alkaloids, suggesting potential utility for managing pain, but further studies are needed to follow up on these in vitro findings. All three kratom alkaloids tested inhibited select cytochrome P450 enzymes, suggesting a potential risk for adverse interactions when kratom is co-consumed with drugs metabolized by these enzymes.
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Affiliation(s)
- D A Todd
- Department of Chemistry and Biochemistry, The University of North Carolina Greensboro, 435 Sullivan Bldg., 301 McIver St., Greensboro, NC, 27402, USA
| | - J J Kellogg
- Department of Chemistry and Biochemistry, The University of North Carolina Greensboro, 435 Sullivan Bldg., 301 McIver St., Greensboro, NC, 27402, USA
- Department of Veterinary and Biomedical Sciences, Pennsylvania State University, University Park, PA, 16802, USA
| | - E D Wallace
- Department of Chemistry and Biochemistry, The University of North Carolina Greensboro, 435 Sullivan Bldg., 301 McIver St., Greensboro, NC, 27402, USA
- Department of Chemistry, The University of North Carolina Chapel Hill, Chapel Hill, NC, 27599, USA
| | - M Khin
- Department of Chemistry and Biochemistry, The University of North Carolina Greensboro, 435 Sullivan Bldg., 301 McIver St., Greensboro, NC, 27402, USA
| | - L Flores-Bocanegra
- Department of Chemistry and Biochemistry, The University of North Carolina Greensboro, 435 Sullivan Bldg., 301 McIver St., Greensboro, NC, 27402, USA
| | - R S Tanna
- Department of Pharmaceutical Sciences, Washington State University, Spokane, WA, 99202, USA
| | - S McIntosh
- Department of Basic Pharmaceutical Sciences, High Point University, High Point, NC, 27268, USA
| | - H A Raja
- Department of Chemistry and Biochemistry, The University of North Carolina Greensboro, 435 Sullivan Bldg., 301 McIver St., Greensboro, NC, 27402, USA
| | - T N Graf
- Department of Chemistry and Biochemistry, The University of North Carolina Greensboro, 435 Sullivan Bldg., 301 McIver St., Greensboro, NC, 27402, USA
| | - S E Hemby
- Department of Basic Pharmaceutical Sciences, High Point University, High Point, NC, 27268, USA
| | - M F Paine
- Department of Pharmaceutical Sciences, Washington State University, Spokane, WA, 99202, USA
| | - N H Oberlies
- Department of Chemistry and Biochemistry, The University of North Carolina Greensboro, 435 Sullivan Bldg., 301 McIver St., Greensboro, NC, 27402, USA
| | - N B Cech
- Department of Chemistry and Biochemistry, The University of North Carolina Greensboro, 435 Sullivan Bldg., 301 McIver St., Greensboro, NC, 27402, USA.
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6
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Wang HY, MacDonald ML, Borgmann-Winter KE, Banerjee A, Sleiman P, Tom A, Khan A, Lee KC, Roussos P, Siegel SJ, Hemby SE, Bilker WB, Gur RE, Hahn CG. mGluR5 hypofunction is integral to glutamatergic dysregulation in schizophrenia. Mol Psychiatry 2020; 25:750-760. [PMID: 30214040 PMCID: PMC7500805 DOI: 10.1038/s41380-018-0234-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 06/18/2018] [Accepted: 07/09/2018] [Indexed: 11/19/2022]
Abstract
Multiple lines of evidence point to glutamatergic signaling in the postsynaptic density (PSD) as a pathophysiologic mechanism in schizophrenia. Integral to PSD glutamatergic signaling is reciprocal interplay between GluN and mGluR5 signaling. We examined agonist-induced mGluR5 signaling in the postmortem dorsolateral prefrontal cortex (DLPFC) derived from 17 patients and age-matched and sex-matched controls. The patient group showed a striking reduction in mGluR5 signaling, manifested by decreases in Gq/11 coupling and association with PI3K and Homer compared to controls (p < 0.01 for all). This was accompanied by increases in serine and tyrosine phosphorylation of mGluR5, which can decrease mGluR5 activity via desensitization (p < 0.01). In addition, we find altered protein-protein interaction (PPI) of mGluR5 with RGS4, norbin, Preso 1 and tamalin, which can also attenuate mGluR5 activity. We previously reported molecular underpinnings of GluN hypofunction (decreased GluN2 phosphorylation) and here we show those of reduced mGluR5 signaling in schizophrenia. We find that reduced GluN2 phosphorylation can be precipitated by attenuated mGluR5 activity and that increased mGluR5 phosphorylation can result from decreased GluN function, suggesting a reciprocal interplay between the two pathways in schizophrenia. Interestingly, the patient group showed decreased mGluR5-GluN association (p < 0.01), a mechanistic basis for the reciprocal facilitation. In sum, we present the first direct evidence for mGluR5 hypoactivity, propose a reciprocal interplay between GluN and mGluR5 pathways as integral to glutamatergic dysregulation and suggest protein-protein interactions in mGluR5-GluN complexes as potential targets for intervention in schizophrenia.
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Affiliation(s)
- Hoau-Yan Wang
- Department of Physiology, Pharmacology and Neuroscience, City University of New York School of Medicine, New York, NY 10031,Department of Biology and Neuroscience, Graduate School of the City University of New York, NY 10016
| | - Mathew L. MacDonald
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104-3403
| | - Karin E. Borgmann-Winter
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104-3403,Department of Child and Adolescent Psychiatry and Behavioral Sciences, Children’s Hospital of Philadelphia, Philadelphia, PA 19104
| | - Anamika Banerjee
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104-3403
| | - Patrick Sleiman
- The Center for Applied Genomics, The Children’s Hospital of Philadelphia, and Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, PA, 19104
| | - Andrew Tom
- Department of Physiology, Pharmacology and Neuroscience, City University of New York School of Medicine, New York, NY 10031
| | - Amber Khan
- Department of Physiology, Pharmacology and Neuroscience, City University of New York School of Medicine, New York, NY 10031,Department of Biology and Neuroscience, Graduate School of the City University of New York, NY 10016
| | - Kuo-Chieh Lee
- Department of Physiology, Pharmacology and Neuroscience, City University of New York School of Medicine, New York, NY 10031
| | - Panos Roussos
- Department of Psychiatry, Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029
| | - Steven J. Siegel
- Department of Psychiatry and the Behavioral Sciences, University of Southern California, Los Angeles, CA, 90007
| | - Scott E Hemby
- Department of Basic Pharmaceutical Sciences, High Point University, High Point, NC, 27106
| | - Warren B. Bilker
- Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, PA 19104
| | - Raquel E. Gur
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104-3403
| | - Chang-Gyu Hahn
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA, 19104-3403, USA.
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7
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Hemby SE, McIntosh S, Leon F, Cutler SJ, McCurdy CR. Abuse liability and therapeutic potential of the Mitragyna speciosa (kratom) alkaloids mitragynine and 7-hydroxymitragynine. Addict Biol 2019; 24:874-885. [PMID: 29949228 DOI: 10.1111/adb.12639] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [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: 02/10/2018] [Revised: 04/20/2018] [Accepted: 05/10/2018] [Indexed: 12/17/2022]
Abstract
Kratom, derived from the plant Mitragyna speciosa, is receiving increased attention as an alternative to traditional opiates and as a replacement therapy for opiate dependence. Mitragynine (MG) and 7-hydroxymitragynine (7-HMG) are major psychoactive constituents of kratom. While MG and 7-HMG share behavioral and analgesic properties with morphine, their reinforcing effects have not been examined to date. 7-HMG, but not MG, substituted for morphine self-administration in a dose-dependent manner in the rat self-administration paradigm. Following the substitution procedure, re-assessment of morphine self-administration revealed a significant increase following 7-HMG and a significant decrease following MG substitution. In a separate cohort, 7-HMG, but not MG, engendered and maintained intravenous self-administration in a dose-dependent manner. The effects of pretreatment with nalxonaxine (NLXZ), a μ1 opiate receptor antagonist, and naltrindole (NTI), a δ opiate receptor antagonist, on 7-HMG and morphine self-administration were also examined. Both NLXZ and NTI reduced 7-HMG self-administration, whereas only NLXZ decreased morphine intake. The present results are the first to demonstrate that 7-HMG is readily self-administered, and the reinforcing effects of 7-HMG are mediated in part by μ and δ opiate receptors. In addition, prior exposure to 7-HMG increased subsequent morphine intake whereas prior exposure to MG decreased morphine intake. The present findings indicate that MG does not have abuse potential and reduces morphine intake, desired characteristics of candidate pharmacotherapies for opiate addiction and withdrawal, whereas 7-HMG should be considered a kratom constituent with high abuse potential that may also increase the intake of other opiates.
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Affiliation(s)
- Scott E. Hemby
- Department of Basic Pharmaceutical Sciences, Fred Wilson School of Pharmacy; High Point University; High Point NC USA
| | - Scot McIntosh
- Department of Basic Pharmaceutical Sciences, Fred Wilson School of Pharmacy; High Point University; High Point NC USA
| | - Francisco Leon
- Department of Medicinal Chemistry, College of Pharmacy; University of Florida; Gainesville FL USA
| | | | - Christopher R. McCurdy
- Department of Medicinal Chemistry, College of Pharmacy; University of Florida; Gainesville FL USA
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8
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Chen R, McIntosh S, Hemby SE, Sun H, Sexton T, Martin TJ, Childers SR. High and low doses of cocaine intake are differentially regulated by dopamine D2 receptors in the ventral tegmental area and the nucleus accumbens. Neurosci Lett 2018; 671:133-139. [PMID: 29454035 DOI: 10.1016/j.neulet.2018.02.026] [Citation(s) in RCA: 13] [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: 11/15/2017] [Revised: 02/01/2018] [Accepted: 02/12/2018] [Indexed: 01/11/2023]
Abstract
Dopamine D2 receptors (D2Rs) in the ventral tegmental area (VTA) and the nucleus accumbens (NAc) are associated with vulnerability to addiction; however, whether D2Rs in these two brain regions play differential roles in regulation of drug intake is unknown. Here, we compared the effect of decreased mRNA level of Drd2 in each region on cocaine self-administration in a dose-response function. Drd2 mRNA levels in rat VTA or NAc were knocked down by bilateral microinjection of lentivirus coding shRNAs against rat Drd2 or scrambled shRNA. Drd2 knockdown was persistent and stable between 20 and 90 days after lentiviral infection. Animals were trained to self-administer cocaine 20 days after Drd2 shRNA treatment. Compared to scrambled shRNA treated rats, Drd2 knockdown in the VTA increased cocaine self-administration at all tested doses (0.02-0.56 mg/kg/infusion) producing an upward shift (both the ascending and descending limb) in the dose-response curve of cocaine self-administration. In contrast, intra-NAc knockdown increased cocaine self-administration only on the ascending limb of the dose-response curve (0.02-0.07 mg/kg/infusion). These data suggest that D2Rs in the VTA, not in the NAc, regulate high-dose cocaine intake. The present study not only demonstrates that low levels of D2Rs in either region increase low doses of cocaine intake, but also reveals for the first time their dissociable roles in limiting high doses of cocaine self-administration.
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Affiliation(s)
- R Chen
- Department of Physiology & Pharmacology, Wake Forest School of Medicine, Winston Salem, NC 27157, United States; Center for the Neurobiology of Addiction Treatment, Wake Forest School of Medicine, Winston Salem, NC 27157, United States; Center for Molecular Signaling, Wake Forest University, Winston Salem, NC 27109, United States.
| | - S McIntosh
- Department of Physiology & Pharmacology, Wake Forest School of Medicine, Winston Salem, NC 27157, United States
| | - S E Hemby
- Department of Physiology & Pharmacology, Wake Forest School of Medicine, Winston Salem, NC 27157, United States
| | - H Sun
- Department of Physiology & Pharmacology, Wake Forest School of Medicine, Winston Salem, NC 27157, United States; Center for the Neurobiology of Addiction Treatment, Wake Forest School of Medicine, Winston Salem, NC 27157, United States
| | - T Sexton
- Department of Physiology & Pharmacology, Wake Forest School of Medicine, Winston Salem, NC 27157, United States; Center for the Neurobiology of Addiction Treatment, Wake Forest School of Medicine, Winston Salem, NC 27157, United States
| | - T J Martin
- Center for the Neurobiology of Addiction Treatment, Wake Forest School of Medicine, Winston Salem, NC 27157, United States; Department of Anesthesiology, Wake Forest School of Medicine, Winston Salem, NC 27157, United States
| | - S R Childers
- Department of Physiology & Pharmacology, Wake Forest School of Medicine, Winston Salem, NC 27157, United States; Center for the Neurobiology of Addiction Treatment, Wake Forest School of Medicine, Winston Salem, NC 27157, United States
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9
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Halene TB, Kozlenkov A, Jiang Y, Mitchell A, Javidfar B, Dincer A, Park R, Wiseman J, Croxson P, Giannaris EL, Hof PR, Roussos P, Dracheva S, Hemby SE, Akbarian S. NeuN+ neuronal nuclei in non-human primate prefrontal cortex and subcortical white matter after clozapine exposure. Schizophr Res 2016; 170:235-44. [PMID: 26776227 PMCID: PMC4740223 DOI: 10.1016/j.schres.2015.12.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [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: 10/15/2015] [Revised: 12/24/2015] [Accepted: 12/28/2015] [Indexed: 12/01/2022]
Abstract
Increased neuronal densities in subcortical white matter have been reported for some cases with schizophrenia. The underlying cellular and molecular mechanisms remain unresolved. We exposed 26 young adult macaque monkeys for 6 months to either clozapine, haloperidol or placebo and measured by structural MRI frontal gray and white matter volumes before and after treatment, followed by observer-independent, flow-cytometry-based quantification of neuronal and non-neuronal nuclei and molecular fingerprinting of cell-type specific transcripts. After clozapine exposure, the proportion of nuclei expressing the neuronal marker NeuN increased by approximately 50% in subcortical white matter, in conjunction with a more subtle and non-significant increase in overlying gray matter. Numbers and proportions of nuclei expressing the oligodendrocyte lineage marker, OLIG2, and cell-type specific RNA expression patterns, were maintained after antipsychotic drug exposure. Frontal lobe gray and white matter volumes remained indistinguishable between antipsychotic-drug-exposed and control groups. Chronic clozapine exposure increases the proportion of NeuN+ nuclei in frontal subcortical white matter, without alterations in frontal lobe volumes or cell type-specific gene expression. Further exploration of neurochemical plasticity in non-human primate brain exposed to antipsychotic drugs is warranted.
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Affiliation(s)
- Tobias B. Halene
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA,Corresponding author: Tobias B. Halene, MD PhD, Icahn School of Medicine at Mount Sinai, Department of Psychiatry, 1470 Madison Ave, Hess 9-105, New York, NY 10029, Tel: 646 627 5529, Fax: 646-537-9583,
| | - Alexey Kozlenkov
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Yan Jiang
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Amanda Mitchell
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Behnam Javidfar
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Aslihan Dincer
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Royce Park
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Jennifer Wiseman
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Paula Croxson
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Eustathia Lela Giannaris
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Patrick R. Hof
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Panos Roussos
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA,Department of Genetics and Genomic Science and Institute for Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Stella Dracheva
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Scott E. Hemby
- Department of Physiology and Pharmacology, Wake Forest University, Winston-Salem, NC, USA
| | - Schahram Akbarian
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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10
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Banerjee A, Wang HY, Borgmann-Winter KE, MacDonald ML, Kaprielian H, Stucky A, Kvasic J, Egbujo C, Ray R, Talbot K, Hemby SE, Siegel SJ, Arnold SE, Sleiman P, Chang X, Hakonarson H, Gur RE, Hahn CG. Src kinase as a mediator of convergent molecular abnormalities leading to NMDAR hypoactivity in schizophrenia. Mol Psychiatry 2015; 20:1091-100. [PMID: 25330739 PMCID: PMC5156326 DOI: 10.1038/mp.2014.115] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 08/19/2014] [Accepted: 08/21/2014] [Indexed: 01/28/2023]
Abstract
Numerous investigations support decreased glutamatergic signaling as a pathogenic mechanism of schizophrenia, yet the molecular underpinnings for such dysregulation are largely unknown. In the post-mortem dorsolateral prefrontal cortex (DLPFC), we found striking decreases in tyrosine phosphorylation of N-methyl-D aspartate (NMDA) receptor subunit 2 (GluN2) that is critical for neuroplasticity. The decreased GluN2 activity in schizophrenia may not be because of downregulation of NMDA receptors as MK-801 binding and NMDA receptor complexes in postsynaptic density (PSD) were in fact increased in schizophrenia cases. At the postreceptor level, however, we found striking reductions in the protein kinase C, Pyk 2 and Src kinase activity that in tandem can decrease GluN2 activation. Given that Src serves as a hub of various signaling mechanisms affecting GluN2 phosphorylation, we postulated that Src hypoactivity may result from convergent alterations of various schizophrenia susceptibility pathways and thus mediate their effects on NMDA receptor signaling. Indeed, the DLPFC of schizophrenia cases exhibit increased PSD-95 and erbB4 and decreased receptor-type tyrosine-protein phosphatase-α (RPTPα) and dysbindin-1, each of which reduces Src activity via protein interaction with Src. To test genomic underpinnings for Src hypoactivity, we examined genome-wide association study results, incorporating 13 394 cases and 34 676 controls. We found no significant association of individual variants of Src and its direct regulators with schizophrenia. However, a protein-protein interaction-based network centered on Src showed significant enrichment of gene-level associations with schizophrenia compared with other psychiatric illnesses. Our results together demonstrate striking decreases in NMDA receptor signaling at the postreceptor level and propose Src as a nodal point of convergent dysregulations affecting NMDA receptor pathway via protein-protein associations.
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Affiliation(s)
- Anamika Banerjee
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104-3403
| | - Hoau-Yan Wang
- Department of Physiology, Pharmacology and Neuroscience, City University of New York Medical School, New York, NY 10031
| | | | - Mathew L. MacDonald
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104-3403
| | - Hagop Kaprielian
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104-3403
| | - Andres Stucky
- Department of Physiology, Pharmacology and Neuroscience, City University of New York Medical School, New York, NY 10031
| | - Jessica Kvasic
- Department of Physiology, Pharmacology and Neuroscience, City University of New York Medical School, New York, NY 10031
| | - Chijioke Egbujo
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104-3403
| | - Rabindranath Ray
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104-3403
| | - Konrad Talbot
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104-3403
| | - Scott E Hemby
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC 27106
| | - Steven J. Siegel
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104-3403
| | - Steven E. Arnold
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104-3403
| | - Patrick Sleiman
- The Center for Applied Genomics, The Children’s Hospital of Philadelphia, and Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, PA, 19104
| | - Xiao Chang
- The Center for Applied Genomics, The Children’s Hospital of Philadelphia, and Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, PA, 19104
| | - Hakon Hakonarson
- The Center for Applied Genomics, The Children’s Hospital of Philadelphia, and Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, PA, 19104
| | - Raquel E. Gur
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104-3403
| | - Chang-Gyu Hahn
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104-3403
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11
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McIntosh S, Sexton T, Pattison LP, Childers SR, Hemby SE. Increased Sensitivity to Cocaine Self-Administration in HIV-1 Transgenic Rats is Associated with Changes in Striatal Dopamine Transporter Binding. J Neuroimmune Pharmacol 2015; 10:493-505. [PMID: 25749646 DOI: 10.1007/s11481-015-9594-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 02/13/2015] [Indexed: 12/14/2022]
Abstract
Cocaine abuse in HIV patients accelerates the progression and severity of neuropathology, motor impairment and cognitive dysfunction compared to non-drug using HIV patients. Cocaine and HIV interact with the dopamine transporter (DAT); however, the effect of their interaction on DAT binding remains understudied. The present study compared the dose-response functions for intravenous self-administration of cocaine and heroin between male HIV-1 transgenic (HIV-1 Tg) and Fischer 344 rats. The cocaine and heroin dose-response functions exhibit an inverted U-shape for both HIV-1 Tg and F344 rats. For cocaine, the number of infusions for each dose on the ascending limb was greater for HIV-1 Tg versus F344 rats. No significant changes in the heroin dose-response function were observed in HIV-1 Tg animals. Following the conclusion of self-administration experiments, DAT binding was assessed in striatal membranes. Saturation binding of the cocaine analog [(125)I] 3β-(4-iodophenyl)tropan-2β-carboxylic acid methyl ester ([(125)I]RTI-55) in rat striatal membranes resulted in binding curves that were best fit to a two-site binding model, allowing for calculation of dissociation constant (Kd) and binding density (Bmax) values that correspond to high- and low-affinity DAT binding sites. Control HIV-1 Tg rats exhibited a significantly greater affinity (i.e., decrease in Kd value) in the low-affinity DAT binding site compared to control F344 rats. Furthermore, cocaine self-administration in HIV-1 Tg rats increased low-affinity Kd (i.e., decreased affinity) compared to levels observed in control F344 rats. Cocaine also increased low-affinity Bmax in HIV-1 Tg rats as compared to controls, indicating an increase in the number of low-affinity DAT binding sites. F344 rats did not exhibit any change in high- or low-affinity Kd or Bmax values following cocaine or heroin self-administration. The increase in DAT affinity in cocaine HIV-1 Tg rats is consistent with the leftward shift of the ascending limb of the cocaine dose-response curve observed in HIV-1 Tg vs. F344 rats, and has major implications for the function of cocaine binding to DAT in HIV patients. The absence of HIV-related changes in heroin intake are likely due to less dopaminergic involvement in the mediation of heroin reward, further emphasizing the preferential influence of HIV on dopamine-related behaviors.
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Affiliation(s)
- Scot McIntosh
- Department of Physiology and Pharmacology, Center for the Neurobiology of Addiction Treatment, Winston-Salem, NC, USA
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12
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Pattison LP, McIntosh S, Sexton T, Childers SR, Hemby SE. Changes in dopamine transporter binding in nucleus accumbens following chronic self-administration cocaine: heroin combinations. Synapse 2014; 68:437-44. [PMID: 24916769 DOI: 10.1002/syn.21755] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [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: 01/23/2014] [Revised: 05/20/2014] [Accepted: 06/04/2014] [Indexed: 01/10/2023]
Abstract
Concurrent use of cocaine and heroin (speedball) has been shown to exert synergistic effects on dopamine neurotransmission in the nucleus accumbens (NAc), as observed by significant increases in extracellular dopamine levels and compensatory elevations in the maximal reuptake rate of dopamine. The present studies were undertaken to determine whether chronic self-administration of cocaine, heroin or a combination of cocaine:heroin led to compensatory changes in the abundance and/or affinity of high- and low-affinity DAT binding sites. Saturation binding of the cocaine analog [(125) I] 3β-(4-iodophenyl)tropan-2β-carboxylic acid methyl ester ([(125) I]RTI-55) in rat NAc membranes resulted in binding curves that were best fit to two-site binding models, allowing calculation of dissociation constant (Kd ) and binding density (Bmax ) values corresponding to high- and low-affinity DAT binding sites. Scatchard analysis of the saturation binding curves clearly demonstrate the presence of high- and low- affinity binding sites in the NAc, with low-affinity sites comprising 85 to 94% of the binding sites. DAT binding analyses revealed that self-administration of cocaine and a cocaine:heroin combination increased the affinity of the low-affinity site for the cocaine congener RTI-55 compared to saline. These results indicate that the alterations observed following chronic speedball self-administration are likely due to the cocaine component alone; thus further studies are necessary to elaborate upon the synergistic effect of cocaine:heroin combinations on the dopamine system in the NAc.
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Affiliation(s)
- Lindsey P Pattison
- Graduate Program in Neuroscience, Wake Forest School of Medicine, Winston-Salem, North Carolina, 27157; Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina, 27157
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13
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Daunais JB, Davenport AT, Helms CM, Gonzales SW, Hemby SE, Friedman DP, Farro JP, Baker EJ, Grant KA. Monkey alcohol tissue research resource: banking tissues for alcohol research. Alcohol Clin Exp Res 2014; 38:1973-81. [PMID: 24942558 DOI: 10.1111/acer.12467] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [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: 12/04/2013] [Accepted: 04/11/2014] [Indexed: 11/29/2022]
Abstract
BACKGROUND An estimated 18 million adults in the United States meet the clinical criteria for diagnosis of alcohol abuse or alcoholism, a disorder ranked as the third leading cause of preventable death. In addition to brain pathology, heavy alcohol consumption is comorbid with damage to major organs including heart, lungs, liver, pancreas, and kidneys. Much of what is known about risk for and consequences of heavy consumption derive from rodent or retrospective human studies. The neurobiological effects of chronic intake in rodent studies may not easily translate to humans due to key differences in brain structure and organization between species, including a lack of higher-order cognitive functions, and differences in underlying prefrontal cortical neural structures that characterize the primate brain. Further, rodents do not voluntarily consume large quantities of ethanol (EtOH) and they metabolize it more rapidly than primates. METHODS The basis of the Monkey Alcohol Tissue Research Resource (MATRR) is that nonhuman primates, specifically monkeys, show a range of drinking excessive amounts of alcohol (>3.0 g/kg or a 12 drink equivalent per day) over long periods of time (12 to 30 months) with concomitant pathological changes in endocrine, hepatic, and central nervous system (CNS) processes. The patterns and range of alcohol intake that monkeys voluntarily consume parallel what is observed in humans with alcohol use disorders and the longitudinal experimental design spans stages of drinking from the EtOH-naïve state to early exposure through chronic abuse. Age- and sex-matched control animals self-administer an isocaloric solution under identical operant procedures. RESULTS The MATRR is a unique postmortem tissue bank that provides CNS and peripheral tissues, and associated bioinformatics from monkeys that self-administer EtOH using a standardized experimental paradigm to the broader alcohol research community. CONCLUSIONS This resource provides a translational platform from which we can better understand the disease processes associated with alcoholism.
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Affiliation(s)
- James B Daunais
- Department of Physiology and Pharmacology , Wake Forest School of Medicine, Winston Salem, North Carolina
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14
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Burnett EJ, Grant KA, Davenport AT, Hemby SE, Friedman DP. The effects of chronic ethanol self-administration on hippocampal 5-HT1A receptors in monkeys. Drug Alcohol Depend 2014; 136:135-42. [PMID: 24467872 PMCID: PMC3962821 DOI: 10.1016/j.drugalcdep.2014.01.002] [Citation(s) in RCA: 13] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 10/02/2013] [Accepted: 01/04/2014] [Indexed: 01/06/2023]
Abstract
BACKGROUND Chronic alcohol consumption reduces brain serotonin and alters the synaptic mechanisms involved in memory formation. Hippocampal 5-HT1A receptors modulate these mechanisms, but the neuroadaptive response of 5HT1A receptors to chronic alcohol self-administration is not well understood. METHODS Hippocampal tissue from monkeys that voluntarily self-administered ethanol for 12 months (n=9) and accompanying controls (n=8) were prepared for in vitro receptor autoradiography and laser capture microdissection. The 5-HT1A receptor antagonist, [(3)H]MPPF, and the agonist, [(3)H]8-OH-DPAT, were used to measure total and G-protein coupled 5-HT1A receptors respectively. The expression of the genes encoding the 5-HT1A receptor and its trafficking protein Yif1B was measured in microdissected dentate gyrus (DG) granule cells and CA1 pyramidal neurons. RESULTS An increase in G-protein coupled, but not total, receptors was observed in the posterior pyramidal cell layer of CA1 in ethanol drinkers compared to controls. Chronic ethanol self-administration was also associated with an up-regulation of total and G-protein coupled 5-HT1A receptors in the posterior DG polymorphic layer. Changes in receptor binding were not associated with concomitant changes in 5-HT1A receptor mRNA expression. Chronic ethanol self-administration was associated with a significant increase in Yif1B gene expression in posterior CA1 pyramidal neurons. CONCLUSIONS Chronic, ethanol self-administration up-regulates hippocampal 5-HT1A receptor density in a region-specific manner that does not appear to be due to alterations at the level of transcription but instead may be due to increased receptor trafficking. Further exploration of the mechanisms mediating chronic ethanol-induced 5-HT1A receptor up-regulation and how hippocampal neurotransmission is altered is warranted.
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Affiliation(s)
- Elizabeth J. Burnett
- Neuroscience Program, Wake Forest University School of Medicine, Winston-Salem, NC, USA,Department of Physiology & Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Kathleen A. Grant
- Department of Behavioral Neuroscience Oregon Health & Science University, Portland, OR, USA
| | - April T. Davenport
- Department of Physiology & Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Scott E. Hemby
- Neuroscience Program, Wake Forest University School of Medicine, Winston-Salem, NC, USA,Department of Physiology & Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - David P. Friedman
- Neuroscience Program, Wake Forest University School of Medicine, Winston-Salem, NC, USA,Department of Physiology & Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, USA,Corresponding author: David P Friedman, Department of Physiology & Pharmacology, Wake Forest University School of Medicine, Medical Center Blvd, Winston-Salem, NC 27157, , (336) 713-7186 tel, (336) 713-7168 fax
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15
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Willard SL, Hemby SE, Register TC, McIntosh S, Shively CA. Altered expression of glial and synaptic markers in the anterior hippocampus of behaviorally depressed female monkeys. Neurosci Lett 2014; 563:1-5. [PMID: 24440617 DOI: 10.1016/j.neulet.2014.01.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [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: 10/10/2013] [Revised: 12/17/2013] [Accepted: 01/07/2014] [Indexed: 01/29/2023]
Abstract
The anterior hippocampus is associated with emotional functioning and hippocampal volume is reduced in depression. We reported reduced neuropil volume and number of glia in the dentate gyrus (DG) and cornu ammonis (CA)1 of the anterior hippocampus in behaviorally depressed adult female cynomolgus macaques. To determine the biochemical correlates of morphometric and behavioral differences between behaviorally depressed and nondepressed adult female monkeys, glial and synaptic transcripts and protein levels were assessed in the DG, CA3 and CA1 of the anterior hippocampus. Glial fibrillary acidic protein (GFAP) was increased whereas spinophilin and postsynaptic density (PSD)-95 protein were decreased in the CA1 of depressed monkeys. GFAP was reciprocally related to spinophilin and PSD-95 protein in the CA1. Gene expression of GFAP paralleled the protein changes observed in the CA1 and was inversely related to serum estradiol levels in depressed monkeys. These results suggest that behavioral depression in female primates is accompanied by astrocytic and synaptic protein alterations in the CA1. Moreover, these findings indicate a potential role for estrogen in modulating astrocyte-mediated impairments in synaptic plasticity.
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Affiliation(s)
- Stephanie L Willard
- Neuroscience Graduate Program, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157-1040, USA.
| | - Scott E Hemby
- Department of Physiology & Pharmacology, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157-1040, USA.
| | - Thomas C Register
- Department of Pathology (Comparative Medicine), Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157-1040, USA.
| | - Scot McIntosh
- Department of Physiology & Pharmacology, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157-1040, USA.
| | - Carol A Shively
- Department of Pathology (Comparative Medicine), Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157-1040, USA.
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16
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Bough KJ, Amur S, Lao G, Hemby SE, Tannu NS, Kampman KM, Schmitz JM, Martinez D, Merchant KM, Green C, Sharma J, Dougherty AH, Moeller FG. Biomarkers for the development of new medications for cocaine dependence. Neuropsychopharmacology 2014; 39:202-19. [PMID: 23979119 PMCID: PMC3857653 DOI: 10.1038/npp.2013.210] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 06/19/2013] [Accepted: 07/01/2013] [Indexed: 01/20/2023]
Abstract
There has been significant progress in personalized drug development. In large part, this has taken place in the oncology field and been due to the ability of researchers/clinicians to discover and develop novel drug development tools (DDTs), such as biomarkers. In cancer treatment research, biomarkers have permitted a more accurate pathophysiological characterization of an individual patient, and have enabled practitioners to target mechanistically the right drug, to the right patient, at the right time. Similar to cancer, patients with substance use disorders (SUDs) present clinically with heterogeneous symptomatology and respond variably to therapeutic interventions. If comparable biomarkers could be identified and developed for SUDs, significant diagnostic and therapeutic advances could be made. In this review, we highlight current opportunities and difficulties pertaining to the identification and development of biomarkers for SUDs. We focus on cocaine dependence as an example. Putative diagnostic, pharmacodynamic (PD), and predictive biomarkers for cocaine dependence are discussed across a range of methodological approaches. A possible cocaine-dependent clinical outcome assessment (COA)--another type of defined DDT--is also discussed. At present, biomarkers for cocaine dependence are in their infancy. Much additional research will be needed to identify, validate, and qualify these putative tools prior to their potential use for medications development and/or application to clinical practice. However, with a large unmet medical need and an estimated market size of several hundred million dollars per year, if developed, biomarkers for cocaine dependence will hold tremendous value to both industry and public health.
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Affiliation(s)
- Kristopher J Bough
- Division of Basic Neuroscience and Behavioral Research, National Institute on Drug Abuse, Bethesda, MD, USA
| | - Shashi Amur
- Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, MD, USA
| | - Guifang Lao
- Division of Pharmacotherapies and Medical Consequences, National Institute on Drug Abuse, Bethesda, MD, USA
| | - Scott E Hemby
- Department of Physiology & Pharmacology, Wake Forest University, Winston-Salem, NC, USA
| | - Nilesh S Tannu
- Department of Psychiatry and Behavioral Sciences, University of Texas—Houston Medical School, Houston, TX, USA
| | - Kyle M Kampman
- Department of Psychiatry, University of Pennsylvania—School of Medicine, Philadelphia, PA, USA
| | - Joy M Schmitz
- Department of Psychiatry and Behavioral Sciences, University of Texas—Houston Medical School, Houston, TX, USA
| | - Diana Martinez
- Department of Psychiatry, Columbia University/New York State University, New York, NY, USA
| | | | - Charles Green
- Department of Pediatrics, University of Texas—Houston Medical School, Houston, TX, USA
| | - Jyoti Sharma
- Department of Cardiovascular Medicine, University of Texas—Houston Medical School, Houston, TX, USA
| | - Anne H Dougherty
- Department of Cardiovascular Medicine, University of Texas—Houston Medical School, Houston, TX, USA
| | - F Gerard Moeller
- Department of Psychiatry and Pharmacology and Toxicology, Virginia Commonwealth University Medical School, Richmond, VA, USA
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17
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McIntosh S, Howell L, Hemby SE. Dopaminergic dysregulation in prefrontal cortex of rhesus monkeys following cocaine self-administration. Front Psychiatry 2013; 4:88. [PMID: 23970867 PMCID: PMC3748374 DOI: 10.3389/fpsyt.2013.00088] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 07/29/2013] [Indexed: 01/20/2023] Open
Abstract
Chronic cocaine administration regulates the expression of several proteins related to dopaminergic signaling and synaptic function in the mesocorticolimbic pathway, including the prefrontal cortex. Functional abnormalities in the prefrontal cortex are hypothesized to be due in part to the expression of proteins involved in dopamine signaling and plasticity. Adult male rhesus monkeys self-administered cocaine (i.v.) under limited (n = 4) and extended access conditions (n = 6). The abundance of surrogate markers of dopamine signaling and plasticity in the dorsolateral prefrontal cortex (DLPFC), orbitofrontal cortex (OFC), and anterior cingulate cortex (ACC) were examined: glycosylated and non-glycosylated forms of the dopamine transporter (efficiency of dopamine transport), tyrosine hydroxylase (TH; marker of dopamine synthesis) and phosphorylated TH at Serine 30 and 40 (markers of enzyme activity), extracellular signal-regulated kinase 1 and 2 (ERK1 and ERK 2), and phosphorylated ERK1 and ERK2 (phosphorylates TH Serine 31; markers of synaptic plasticity), and markers of synaptic integrity, spinophilin and post-synaptic density protein 95 (roles in dopamine signaling and response to cocaine). Extended cocaine access increased non-glycosylated and glycosylated DAT in DLPFC and OFC. While no differences in TH expression were observed between groups for any of the regions, extended access induced significant elevations in pTH(Ser31) in all regions. In addition, a slight but significant reduction in phosphorylated pTH(Ser40) was found in the DLPFC. Phosphorylated ERK2 was increased in all regions; however, pERK1 was decreased in ACC and OFC but increased in DLPFC. PSD-95 was increased in the OFC but not in DLPFC or ACC. Furthermore, extended cocaine self-administration elicited significant increases in spinophilin protein expression in all regions. Results from the study provide insight into the biochemical alterations occurring in primate prefrontal cortex.
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Affiliation(s)
- Scot McIntosh
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine , Winston-Salem, NC , USA ; Center for Neurobiology of Addiction Treatment, Wake Forest University School of Medicine , Winston-Salem, NC , USA
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18
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Pattison LP, McIntosh S, Budygin EA, Hemby SE. Differential regulation of accumbal dopamine transmission in rats following cocaine, heroin and speedball self-administration. J Neurochem 2012; 122:138-46. [PMID: 22443145 DOI: 10.1111/j.1471-4159.2012.07738.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Cocaine/heroin combinations (speedball) exert synergistic neurochemical and behavioral effects that are thought to contribute to the increased abuse potential and subjective effects reported by polydrug users. In vivo fast-scan cyclic voltammetry was used to examine the effects of chronic intravenous self-administration (25 consecutive sessions) of cocaine (250 μg/inf), heroin (4.95 μg/inf) and speedball (250/4.95 μg/inf cocaine/heroin) on changes in electrically evoked dopamine (DA) efflux, maximal rate of DA uptake (V(max)) and the apparent affinity (K(m)) of the DA transporter in the nucleus accumbens. The increase in electrically evoked DA was comparable following cocaine and speedball injection; however, heroin did not increase evoked DA. DA transporter K(m) values were similarly elevated following cocaine and speedball, but unaffected by heroin. However, speedball self-administration significantly increased baseline V(max), while heroin and cocaine did not change baseline V(max), compared with the baseline V(max) values of drug-naïve animals. Overall, elevated DA clearance is a likely consequence of synergistic elevations of nucleus accumbens extracellular DA concentrations by chronic speedball self-administration, as reported previously in microdialysis studies. The present results indicate neuroadaptive processes that are unique to cocaine/heroin combinations and cannot be readily explained by simple additivity of changes observed with cocaine and heroin alone.
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Affiliation(s)
- Lindsey P Pattison
- Graduate Program in Neuroscience, Wake Forest University School of Medicine, Winston-Salem, NC, USA
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Acosta G, Freidman DP, Grant KA, Hemby SE. Alternative splicing of AMPA subunits in prefrontal cortical fields of cynomolgus monkeys following chronic ethanol self-administration. Front Psychiatry 2011; 2:72. [PMID: 22291662 PMCID: PMC3249828 DOI: 10.3389/fpsyt.2011.00072] [Citation(s) in RCA: 19] [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] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Accepted: 11/26/2011] [Indexed: 01/18/2023] Open
Abstract
Functional impairment of the orbital and medial prefrontal cortex underlies deficits in executive control that characterize addictive disorders, including alcohol addiction. Previous studies indicate that alcohol alters glutamate neurotransmission and one substrate of these effects may be through the reconfiguration of the subunits constituting ionotropic glutamate receptor (iGluR) complexes. Glutamatergic transmission is integral to cortico-cortical and cortico-subcortical communication and alcohol-induced changes in the abundance of the receptor subunits and/or their splice variants may result in critical functional impairments of prefrontal cortex in alcohol dependence. To this end, the effects of chronic ethanol self-administration on glutamate receptor ionotropic AMPA (GRIA) subunit variant and kainate (GRIK) subunit mRNA expression were studied in the orbitofrontal cortex (OFC), dorsolateral prefrontal cortex (DLPFC), and anterior cingulate cortex (ACC) of male cynomolgus monkeys. In DLPFC, total AMPA splice variant expression and total kainate receptor subunit expression were significantly decreased in alcohol drinking monkeys. Expression levels of GRIA3 flip and flop and GRIA4 flop mRNAs in this region were positively correlated with daily ethanol intake and blood ethanol concentrations (BEC) averaged over the 6 months prior to necropsy. In OFC, AMPA subunit splice variant expression was reduced in the alcohol treated group. GRIA2 flop mRNA levels in this region were positively correlated with daily ethanol intake and BEC averaged over the 6 months prior to necropsy. Results from these studies provide further evidence of transcriptional regulation of iGluR subunits in the primate brain following chronic alcohol self-administration. Additional studies examining the cellular localization of such effects in the framework of primate prefrontal cortical circuitry are warranted.
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Affiliation(s)
- Glen Acosta
- Department of Physiology and Pharmacology, Wake Forest University Winston-Salem, NC, USA
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20
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Lynch WJ, Piehl KB, Acosta G, Peterson AB, Hemby SE. Aerobic exercise attenuates reinstatement of cocaine-seeking behavior and associated neuroadaptations in the prefrontal cortex. Biol Psychiatry 2010; 68:774-7. [PMID: 20692647 PMCID: PMC2949528 DOI: 10.1016/j.biopsych.2010.06.022] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Revised: 06/23/2010] [Accepted: 06/24/2010] [Indexed: 01/10/2023]
Abstract
BACKGROUND Exercise has recently been suggested as an attractive alternative to pharmacotherapy for treating drug addiction. The goal of this study was to determine, using an animal model, whether aerobic exercise may block reinstatement of cocaine-seeking and its underlying neurobiology (i.e., neuronal signaling in the prefrontal cortex). METHODS Following acquisition and 10 days of 24-hour access to cocaine (1.5 mg/kg/infusion) or saline under a discrete trial procedure (four infusions/hr), rats began a 14-day abstinence period. During this period, rats were either given access to a running-wheel for 2-hours each day or placed in similar boxes with the wheel locked. Cocaine-seeking was assessed following the 14th day of abstinence using a within-session extinction/cue-induced reinstatement procedure. Neuronal activity was assessed by examining phosphorylated levels of extracellular signal-regulated kinase (pERK) using Western blot analysis. RESULTS Wheel running reduced cocaine-seeking during both extinction and reinstatement. Cocaine-seeking was positively associated with pERK levels in the prefrontal cortex. Although pERK levels were not different among saline controls, in the cocaine group, pERK levels were significantly decreased by exercise. CONCLUSIONS Aerobic exercise may reduce relapse vulnerability by preventing the increase in cocaine-seeking and associated neuroadaptations in the prefrontal cortex that develop over an abstinence period.
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Affiliation(s)
- Wendy J Lynch
- Department of Psychiatry and Neurobehavioral Sciences, University of Virginia, Charlottesville, VA 22911, USA.
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21
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Pattison LP, Bonin KD, Hemby SE, Budygin EA. Speedball induced changes in electrically stimulated dopamine overflow in rat nucleus accumbens. Neuropharmacology 2010; 60:312-7. [PMID: 20869972 DOI: 10.1016/j.neuropharm.2010.09.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2010] [Revised: 09/10/2010] [Accepted: 09/14/2010] [Indexed: 11/26/2022]
Abstract
Cocaine/heroin combinations (speedball) induce a synergistic elevation in extracellular dopamine concentrations ([DA](e)) in the nucleus accumbens (NAc) that can explain the increased abuse liability of speedball. To further delineate the mechanism of this neurochemical synergism, in vivo fast-scan cyclic voltammetry (FSCV) was used to compare NAc DA release and reuptake kinetic parameters following acute administration of cocaine, heroin and speedball in drug-naïve rats. These parameters were extracted from accumbal DA overflow induced by electrical stimulation of the ventral tegmental area. Evoked DA efflux was increased following both cocaine and speedball delivery, whereas heroin did not significantly change evoked DA release from baseline. DA efflux was significantly greater following cocaine compared to speedball. However, DA transporter (DAT) apparent affinity (K(m)) values were similarly elevated following cocaine and speedball administration, but unaffected by heroin. Neither drug induced substantial changes in the maximal reuptake rate (V(max)). These data, combined with published microdialysis and electrophysiological results, indicate that the combination of cocaine-induced competitive inhibition of DAT and the increase in the DA release elicited by heroin is responsible for the synergistic increase in ([DA](e)) induced by speedball.
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Affiliation(s)
- Lindsey P Pattison
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC 27101, USA
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22
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Abdolahi A, Acosta G, Breslin FJ, Hemby SE, Lynch WJ. Incubation of nicotine seeking is associated with enhanced protein kinase A-regulated signaling of dopamine- and cAMP-regulated phosphoprotein of 32 kDa in the insular cortex. Eur J Neurosci 2010; 31:733-41. [PMID: 20384816 DOI: 10.1111/j.1460-9568.2010.07114.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A recent clinical study demonstrated that damage to the insular cortex can disrupt tobacco addiction. The neurobiological mechanisms for this effect are not yet understood. In this study we used an animal model of nicotine addiction to examine the possibility that changes in insular cortex levels of dopamine (DA)- and cAMP-regulated phosphoprotein of 32 kDa (DARPP-32), a phosphoprotein enriched in DA neurons containing DA D1 receptors, may be associated with changes in vulnerability to nicotine addiction. Once rats acquired self-administration, they were given unlimited access to nicotine (0.01 mg/kg/infusion) for 23 h/day for a total of 10 days. Each infusion was paired with a visual cue (stimulus light) and auditory cue (sound of pump). Nicotine seeking, as assessed under a cue-induced reinstatement paradigm, and markers of DARPP-32 signaling, as assessed using western blot analysis, were examined in separate groups of rats at two different abstinent intervals: 1 and 7 days. Consistent with findings with other drugs of abuse, rats in the 7-day abstinence group took longer to extinguish and responded at higher levels during reinstatement testing as compared with rats in the 1-day reinstatement group. Relative to saline controls, rats in the 7-day but not the 1-day abstinence group had higher levels of DARPP-32 phosphorylated at the protein kinase A site in the insular cortex. These results demonstrate incubation of drug seeking following extended access to nicotine self-administration and suggest that enhanced protein kinase A signaling in the insular cortex via phosphorylation of DARPP-32 at Thr34 is associated with this effect.
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Affiliation(s)
- Amir Abdolahi
- Department of Psychiatry and Neurobehavioral Sciences, University of Virginia, 1670 Discovery Drive, Charlottesville, VA 22911, USA
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Abstract
Until recently, knowledge of the impact of abused drugs on gene and protein expression in the brain was limited to less than 100 targets. With the advent of high-throughput genomic and proteomic techniques, investigators are now able to evaluate changes across the entire genome and across thousands of proteins in defined brain regions and generate expression profiles of vulnerable neuroanatomical substrates in rodent and nonhuman primate drug abuse models and in human post-mortem brain tissue from drug abuse victims. The availability of gene and protein expression profiles will continue to expand our understanding of the short- and long-term consequences of drug addiction and other addictive disorders and may provide new approaches or new targets for pharmacotherapeutic intervention. This review summarizes several important genomic and proteomic studies of cocaine abuse/addiction from rodent, nonhuman primate, and human postmortem studies of cocaine abuse and explores how these studies have advanced our understanding of addiction.
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Affiliation(s)
- Scott E Hemby
- Department of Physiology and Pharmacology, Center for the Neurobiology of Addiction and Treatment, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
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24
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Tannu NS, Howell LL, Hemby SE. Integrative proteomic analysis of the nucleus accumbens in rhesus monkeys following cocaine self-administration. Mol Psychiatry 2010; 15:185-203. [PMID: 18504425 PMCID: PMC3272768 DOI: 10.1038/mp.2008.53] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2007] [Revised: 03/12/2008] [Accepted: 04/10/2008] [Indexed: 11/09/2022]
Abstract
The reinforcing effects and long-term consequences of cocaine self-administration have been associated with brain regions of the mesolimbic dopamine pathway, namely the nucleus accumbens (NAc). Studies of cocaine-induced biochemical adaptations in rodent models have advanced our knowledge; however, unbiased detailed assessments of intracellular alterations in the primate brain are scarce, yet essential, to develop a comprehensive understanding of cocaine addiction. To this end, two-dimensional difference in gel electrophoresis (2D-DIGE) was used to compare changes in cytosolic protein abundance in the NAc between rhesus monkeys self-administering cocaine and controls. Following image normalization, spots with significantly differential image intensities (P<0.05) were identified, excised, trypsin digested and analyzed by matrix-assisted laser-desorption ionization time-of-flight time-of-flight (MALDI-TOF-TOF). In total, 1098 spots were subjected to statistical analysis with 22 spots found to be differentially abundant of which 18 proteins were positively identified by mass spectrometry. In addition, approximately 1000 protein spots were constitutively expressed of which 21 proteins were positively identified by mass spectrometry. Increased levels of proteins in the cocaine-exposed monkeys include glial fibrillary acidic protein, syntaxin-binding protein 3, protein kinase C isoform, adenylate kinase isoenzyme 5 and mitochondrial-related proteins, whereas decreased levels of proteins included beta-soluble N-ethylmaleimide-sensitive factor attachment protein and neural and non-neural enolase. Using a complimentary proteomics approach, the differential expression of phosphorylated proteins in the cytosolic fraction of these subjects was examined. Two-dimensional gel electrophoresis (2DGE) was followed by gel staining with Pro-Q Diamond phosphoprotein gel stain, enabling differentiation of approximately 150 phosphoprotein spots between the groups. Following excision and trypsin digestions, MALDI-TOF-TOF was used to confirm the identity of 15 cocaine-altered phosphoproteins. Significant increased levels were detected for gamma-aminobutyric acid type A receptor-associated protein 1, 14-3-3 gamma-protein, glutathione S-transferase and brain-type aldolase, whereas significant decreases were observed for beta-actin, Rab GDP-dissociation inhibitor, guanine deaminase, peroxiredoxin 2 isoform b and several mitochondrial proteins. Results from these studies indicate coordinated dysregulation of proteins related to cell structure, signaling, metabolism and mitochondrial function. These data extend and compliment previous studies of cocaine-induced biochemical alterations in human postmortem brain tissue, using an animal model that closely recapitulates the human condition and provide new insight into the molecular basis of the disease and potential targets for pharmacotherapeutic intervention.
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Affiliation(s)
- NS Tannu
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - LL Howell
- Neuroscience Division, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA, USA
| | - SE Hemby
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
- Department of Psychiatry and Behavioral Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, USA
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Acosta G, Hasenkamp W, Daunais JB, Friedman DP, Grant KA, Hemby SE. Ethanol self-administration modulation of NMDA receptor subunit and related synaptic protein mRNA expression in prefrontal cortical fields in cynomolgus monkeys. Brain Res 2010; 1318:144-54. [PMID: 20043891 DOI: 10.1016/j.brainres.2009.12.050] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Revised: 12/14/2009] [Accepted: 12/16/2009] [Indexed: 01/18/2023]
Abstract
BACKGROUND Functional impairment of the orbital and medial prefrontal cortex underlies deficits in executive control that characterize addictive disorders, including alcohol addiction. Previous studies indicate that alcohol alters glutamate neurotransmission and one substrate of these effects may be through the reconfiguration of the subunits constituting ionotropic glutamate receptor (iGluR) complexes. Glutamatergic transmission is integral to cortico-cortical and cortico-subcortical communication, and alcohol-induced changes in the abundance of the receptor subunits and/or their splice variants may result in critical functional impairments of prefrontal cortex in the alcohol-addicted state. METHODS AND RESULTS The effects of chronic ethanol self-administration on glutamate receptor ionotropic NMDA (GRIN), as well as GRIN1 splice variant mRNA expression was studied in the orbitofrontal cortex (OFC; Area 13), dorsolateral prefrontal cortex (DLPFC; Area 46) and anterior cingulate cortex (ACC; Area 24) of male cynomolgus monkeys. Chronic ethanol self-administration resulted in significant changes in the expression of NMDA subunit mRNA expression in the DLPFC and OFC, but not the ACC. In DLPFC, the overall expression of NMDA subunits was significantly decreased in ethanol treated monkeys. Slight but significant changes were observed for synaptic associated protein 102 kD (SAP102) and neuronal nitric oxide synthase (nNOS) mRNAs. In OFC, the NMDAR1 variant GRIN1-1 was reduced while GRIN1-2 was increased. Furthermore, no significant changes in GFAP protein levels were observed in either the DLPFC or OFC. CONCLUSION Results from these studies provide the first demonstration of posttranscriptional regulation of iGluR subunits in the primate brain following long-term ethanol self-administration. Furthermore, changes in these transcripts do not appear to reflect changes in glial activation or loss. Further studies examining the expression and cellular localization of subunit proteins and receptor pharmacology would shed more light on the findings reported here.
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Affiliation(s)
- Glen Acosta
- Department of Physiology and Pharmacology, Wake Forest University, Winston-Salem, NC 27157, USA
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26
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Abstract
The ability to model aspects of human addictive behaviors in laboratory animals provides an important avenue for gaining insight into the biochemical alterations associated with drug intake and the identification of targets for medication development to treat addictive disorders. The intravenous self-administration procedure provides the means to model the reinforcing effects of abused drugs and to correlate biochemical alterations with drug reinforcement. In this chapter, we provide a detailed methodology for rodent intravenous self-administration and the isolation and preparation of proteins from dissected brain regions for Western blot analysis and high-throughput proteomic analysis. Examples of cocaine-induced alterations in the abundances of ionotropic glutamate receptor subunits in reinforcement-related brain regions are provided.
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Affiliation(s)
- Scott E Hemby
- Department of Physiology & Pharmacology and Psychiatry, Wake Forest University School of Medicine, Winston-Salem, NC, USA.
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27
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Abstract
Quantitative proteomics is the workhorse of the modern proteomics initiative. The gel-based and MuDPIT approaches have facilitated vital advances in the measurement of protein expression alterations in normal and disease phenotypic states. The methodological advance in two-dimensional gel electrophoresis (2DGE) has been the multiplexing fluorescent two-dimensional fluorescence difference gel electrophoresis (2D-DIGE). 2D-DIGE is based on direct labeling of lysine groups on proteins with cyanine CyDye DIGE Fluor minimal dyes before isoelectric focusing, enabling the labeling of 2-3 samples with different dyes and electrophoresis of all the samples on the same 2D gel. This capability minimizes spot pattern variability and the number of gels in an experiment while providing simple, accurate and reproducible spot matching. This protocol can be completed in 3-5 weeks depending on the sample size of the experiment and the level of expertise of the investigator.
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Affiliation(s)
- Nilesh S Tannu
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA
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Backes EN, Hemby SE. Contribution of ventral tegmental GABA receptors to cocaine self-administration in rats. Neurochem Res 2007; 33:459-67. [PMID: 17943439 DOI: 10.1007/s11064-007-9454-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2007] [Accepted: 07/20/2007] [Indexed: 11/29/2022]
Abstract
Recent evidence has suggested that compounds affecting GABAergic transmission may provide useful pharmacological tools for the treatment of cocaine addiction. Using a rat model of self-administration, the present study examined the effects of GABA agonists and antagonists injected directly into the ventral tegmental area (VTA) on cocaine intake in rats trained to self-administer cocaine (0, 125, 250 and 500 microg/infusion) under an FR5 schedule of reinforcement. Separate groups of rats received bilateral intra-VTA injections of the GABA-A antagonist picrotoxin (34 ng/side, n = 7; 68 ng/side, n = 8), GABA-A agonist muscimol (14 ng/side, n = 8), GABA-B agonist baclofen (56 ng/side, n = 7; 100 ng/side, n = 6), picrotoxin (68 ng/side) co-injected with the GABA-B antagonist 2-hydroxysaclofen (100 ng/side, n = 7; 2 microg/side, n = 8) or artificial cerebrospinal fluid (aCSF, n = 6) to assess the effects of the various compounds on the cocaine self-administration dose-response curve. Both picrotoxin and baclofen reduced responding maintained by cocaine, whereas muscimol had no effect on responding. In contrast, neither picrotoxin (n = 6) nor baclofen (n = 8) affected responding maintained by food. Interestingly, 2-hydroxysaclofen effectively blocked the suppression of responding produced by picrotoxin, suggesting that both picrotoxin and baclofen exert their effects via activation of GABA-B receptors. Additionally, these effects appear to be specific to cocaine reinforcement, supporting current investigation of baclofen as a treatment for cocaine addiction.
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Affiliation(s)
- E N Backes
- Neuroscience Graduate Program, Emory University School of Medicine, Atlanta, GA, USA
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29
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Abstract
Background Macaca mulatta is one of the most utilized non-human primate species in biomedical research offering unique behavioral, neuroanatomical, and neurobiochemcial similarities to humans. This makes it a unique organism to model various diseases such as psychiatric and neurodegenerative illnesses while also providing insight into the complexities of the primate brain. A major obstacle in utilizing rhesus monkey models for human disease is the paucity of protein annotations for this species (~42,000 protein annotations) compared to 330,210 protein annotations for humans. The lack of available information limits the use of rhesus monkey for proteomic scale studies which rely heavily on database searches for protein identification. While characterization of proteins of interest from Macaca mulatta using the standard database search engines (e.g., MASCOT) can be accomplished, searches must be performed using a 'broad species database' which does not provide optimal confidence in protein annotation. Therefore, it becomes necessary to determine partial or complete amino acid sequences using either manual or automated de novo peptide sequence analysis methods. Results The recently popularized MALDI-TOF-TOF mass spectrometer yields a complex MS/MS fragmentation pattern difficult to characterize by manual de novo sequencing method on a proteomics scale. Therefore, PEAKS assisted de novo sequencing was performed on nucleus accumbens cytosolic proteins from Macaca mulatta. The most abundant peptide fragments 'b-ions and y-ions', the less abundant peptide fragments 'a-ions' as well as the immonium ions were utilized to develop confident and complete peptide sequences de novo from MS/MS spectra. The generated sequences were used to perform homology searches to characterize the protein identification. Conclusion The current study validates a robust method to confidently characterize the proteins from an incomplete sequence database of Macaca mulatta, using the PEAKS de novo sequencing software, facilitating the use of this animal model in various neuroproteomics studies.
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Affiliation(s)
- Nilesh S Tannu
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Scott E Hemby
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
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Tannu N, Mash DC, Hemby SE. Cytosolic proteomic alterations in the nucleus accumbens of cocaine overdose victims. Mol Psychiatry 2007; 12:55-73. [PMID: 17075605 PMCID: PMC2442480 DOI: 10.1038/sj.mp.4001914] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2006] [Revised: 08/01/2006] [Accepted: 08/21/2006] [Indexed: 11/08/2022]
Abstract
Chronic cocaine use in humans and animal models is known to lead to pronounced alterations in neuronal function in the nucleus accumbens (NAc), a brain region associated with drug reinforcement. Two-dimensional gel electrophoresis was used to compare protein alterations in the NAc between cocaine overdose (COD) victims (n=10) and controls (n=10). Following image normalization, spots with significantly differential image intensities (P<0.05) were identified, excised, trypsin digested and analyzed by matrix-assisted laser desorption ionization-time of flight-time of flight. A total of 1407 spots were found to be present in a minimum of five subjects per group and the intensity of 18 spots was found to be differentially abundant between the groups, leading to positive identification of 15 proteins by peptide mass fingerprinting (PMF). Of an additional 37 protein spots that were constitutively expressed, 32 proteins were positively identified by PMF. Increased proteins in COD included beta-tubulin, liprin-alpha3 and neuronal enolase, whereas decreased proteins included parvalbumin, ATP synthase beta-chain and peroxiredoxin 2. The present data provide a preliminary protein profile of COD, suggesting the involvement of novel proteins and pathways in the expression of this complex disease. Additional studies are warranted to further characterize alterations in the differentially regulated proteins. Understanding the coordinated involvement of multiple proteins in cocaine abuse provides insight into the molecular basis of the disease and offers new targets for pharmacotherapeutic intervention for drug abuse-related disorders.
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Affiliation(s)
- N Tannu
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - DC Mash
- Department of Neurology, University of Miami School of Medicine, Miami, FL, USA
| | - SE Hemby
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
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Hemby SE, O'connor JA, Acosta G, Floyd D, Anderson N, McCool BA, Friedman D, Grant KA. Ethanol-Induced Regulation of GABAA Subunit mRNAs in Prefrontal Fields of Cynomolgus Monkeys. Alcohol Clin Exp Res 2006; 30:1978-85. [PMID: 17117962 DOI: 10.1111/j.1530-0277.2006.00254.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Recent evidence indicates that functional impairment of the orbital and medial fields of the prefrontal cortex may underlie the deficits in executive control of behavior that characterize addictive disorders, including alcohol addiction. Moreover, previous studies have indicated that alcohol alters GABA neurotransmission and one substrate of these effects may be through the reconfiguration of the subunits constituting the GABA(A) receptor complex. Given that GABAergic transmission has an integral role in cortical processing, influencing local and interregional communication, understanding alcohol-induced alterations in GABA(A) receptors in prefrontal fields of the primate brain may provide insight into the functional impairment of these brain regions in the alcohol-addicted state and extend our understanding of the molecular consequences of long-term use in these critical brain regions. METHODS AND RESULTS To address this problem, the effects of chronic ethanol self-administration in male cynomolgus monkeys on GABA(A) receptor subunit mRNA expression was studied in 3 frontal cortical fields: orbitofrontal cortex (OFC; area 13), anterior cingulate cortex (ACC; area 24), and the dorsolateral prefrontal cortex (DLPFC; area 46). Quantitative polymerase chain reaction revealed significant alterations in GABA(A) subunit mRNA expression in the OFC and DLPFC but not in the ACC. Specifically, expression of the alpha2, alpha4, beta1, beta3, and gamma1 to gamma3 subunit mRNAs was significantly less in the OFC, whereas the expression of beta1, beta2, gamma1, and delta subunit mRNAs was less in the DLPFC of alcohol-treated monkeys. CONCLUSION These findings suggest that ethanol-induced alterations in GABA(A) function may be due to alterations in GABA(A) subunit mRNA levels and subunit-specific alterations are selective to particular cortical fields.
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Affiliation(s)
- Scott E Hemby
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA.
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O'Connor JA, Hasenkamp W, Horman BM, Muly EC, Hemby SE. Region specific regulation of NR1 in rhesus monkeys following chronic antipsychotic drug administration. Biol Psychiatry 2006; 60:659-62. [PMID: 16806093 DOI: 10.1016/j.biopsych.2006.03.044] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2005] [Revised: 01/26/2006] [Accepted: 03/15/2006] [Indexed: 10/24/2022]
Abstract
BACKGROUND Altered NMDA receptor subunit protein levels have been reported in various regions of the schizophrenic brain; however, chronic antipsychotic administration in schizophrenic subjects may confound interpretation. METHODS The effects of chronic antipsychotic drug administration (haloperidol and clozapine) on protein levels of NR1, NR2A and NR2B proteins were evaluated in the nucleus accumbens (NAc), putamen (PUT), dorsolateral prefrontal cortex (DLPFC), superior temporal gyrus (STG), and entorhinal cortex (EC) of rhesus monkeys using Western blot analysis. RESULTS Haloperidol administration significantly decreased NR1 expression in the DLPFC. In contrast, NR2B expression was not affected by antipsychotic administration in any brain region examined. NR2A was not reliably detected in any of the brain regions. CONCLUSIONS Results indicate that the NR1 subunit in the DLPFC may be a substrate for antipsychotic action and that glutamatergic hypofunction in the DLPFC commonly associated with cognitive dysfunction in schizophrenia may be associated with haloperidol administration.
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Affiliation(s)
- Joann A O'Connor
- Yerkes National Primate Research Center, Neuroscience Division, Atlanta, Georgia, USA
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33
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Abstract
Analyzing a large number of unfixed gels in a 2-D fluorescence difference gel electrophoresis (2-DIGE) experiment presents a challenge of avoiding variable protein diffusion within and across the comparison groups. The characteristics of protein detection and quantitation in a 2-D differential in gel fluorescence experiment were compared for gels with and without protein fixation. The current study tests and concludes that when dealing with a large sample size with variable protein diffusion across the 2-D gel over a period of 2-4 days, it is a preferred choice to fix the gel without affecting the protein quantitation.
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Affiliation(s)
- Nilesh Tannu
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC 27501, USA
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O’Connor J, Muly EC, Hemby SE. Molecular mapping of striatal subdivisions in juvenile Macaca Mulata. Exp Neurol 2006; 198:326-37. [PMID: 16455077 PMCID: PMC5076375 DOI: 10.1016/j.expneurol.2005.11.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2005] [Revised: 11/23/2005] [Accepted: 11/23/2005] [Indexed: 11/21/2022]
Abstract
The striatum of the primate brain can be subdivided into three distinct anatomical subregions: caudate (CAU), putamen (PUT), and ventral striatum (VS). Although these subregions share several anatomical connections, cell morphological, and histochemical features, they differ considerably in their vulnerability to different neurological and psychiatric diseases, and these brain regions have significantly different functions in health and disease. In order to better understand the molecular underpinnings of the different disease and functional vulnerabilities, transcriptional profiles were generated from the CAU, PUT, and VS of five juvenile rhesus macaques (Macaca mulatta) using human cDNA neuromicroarrays containing triplicate spots of 1227 cDNAs. Differences in microarray gene expression were assessed using z score analysis and 1.5-fold change between paired subregions. Clustering of genes based on dissimilarity of expression patterns between regions revealed subregion specific expression profiles encoding G-protein-coupled receptor signaling transcripts, transcription factors, kinases and phosphatases, and cell signaling and signal transduction transcripts. Twelve transcripts were examined using quantitative real-time PCR (qPCR), and 81% demonstrated alterations similar to those seen with microarray analysis, some of which were statistically significant. Subregion specific transcription profiles support the anatomical differentiation and potential disease vulnerabilities of the respective subregions.
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Affiliation(s)
- Joann O’Connor
- Molecular and Systems Pharmacology Program, Graduate Division of Biological and Behavioral Sciences, Emory University, Atlanta, GA 30322, USA
| | - Emil C. Muly
- Department of Psychiatry and Behavioral Sciences, Emory University, Atlanta, GA 30322, USA
- Yerkes National Primate Research Center, Division of Neuroscience, Emory University, Atlanta, GA 30329, USA
| | - Scott E. Hemby
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
- Corresponding author. Fax: +1 336 716 8501. (S.E. Hemby)
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Hemby SE, Tang W, Muly EC, Kuhar MJ, Howell L, Mash DC. Cocaine-induced alterations in nucleus accumbens ionotropic glutamate receptor subunits in human and non-human primates. J Neurochem 2006; 95:1785-93. [PMID: 16363995 PMCID: PMC3843355 DOI: 10.1111/j.1471-4159.2005.03517.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Chronic cocaine and withdrawal induce significant alterations in nucleus accumbens (NAc) glutamatergic function in humans and rodent models of cocaine addiction. Dysregulation of glutamatergic function of the prefrontal cortical-NAc pathway has been proposed as a critical substrate for unmanageable drug seeking. Previously, we demonstrated significant up-regulation of NMDA, (+/-)-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and kainate receptor subunit mRNAs and protein levels in the ventral tegmental area (VTA), but not the substantia nigra, of cocaine overdose victims (COD). The present study was undertaken to examine the extent of altered ionotropic glutamate receptor (iGluR) subunit expression in the NAc and the putamen in cocaine overdose victims. Results revealed statistically significant increases in the NAc, but not in the putamen, of NMDA receptor subunit (NR)1 and glutamate receptor subunit (GluR)2/3 wit trends in GluR1 and GluR5 in COD. These results extend our previous finding and indicate pathway-specific alterations in iGluRs in COD. In order to determine that changes were related to cocaine intake and not to other factors in the COD victims, we examined the effects of cocaine intravenous self-administration in rhesus monkeys for 18 months (unit dose of 0.1 mg/kg/injection and daily drug intake of 0.5 mg/kg/session). Total drug intake for the group of four monkeys was 37.9 +/- 4.6 mg/kg. Statistically significant elevations were observed for NR1, GluR1, GluR2/3 and GluR5 (p < 0.05) and a trend towards increased NR1 phosphorylated at serine 896 (p = 0.07) in the NAc but not putamen of monkeys self-administering cocaine compared with controls. These results extend previous results by demonstrating an up-regulation of NR1, GluR2/3 and GluR5 in the NAc and suggest these alterations are pathway specific. Furthermore, these changes may mediate persistent drug intake and craving in the human cocaine abuser.
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Affiliation(s)
- Scott E Hemby
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA.
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Abstract
Until recently, knowledge of the impact of abuse drugs on gene and protein expression in the brain was limited to less than 100 targets. With the advent of high-throughput genomic and proteomic techniques investigators are now able to evaluate changes across the entire genome and across thousands of proteins in defined brain regions and generate expression profiles of vulnerable neuroanatomical substrates in rodent and non-human primate drug abuse models and in human post-mortem brain tissue from drug abuse victims. The availability of gene and protein expression profiles will continue to expand our understanding of the short- and long-term consequences of drug addiction and other addictive disorders and may provide new approaches or new targets for pharmacotherapeutic intervention. This chapter will review gene expression data from rodent, non-human primate and human post-mortem studies of cocaine abuse and will provide a preliminary proteomic profile of human cocaine abuse and explore how these studies have advanced our understanding of addiction.
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Affiliation(s)
- Scott E. Hemby
- Corresponding author. Tel.:336-716-8620; Fax: 336-716-8501;
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Smith JE, Co C, Coller MD, Hemby SE, Martin TJ. Self-administered heroin and cocaine combinations in the rat: additive reinforcing effects-supra-additive effects on nucleus accumbens extracellular dopamine. Neuropsychopharmacology 2006; 31:139-50. [PMID: 15956989 PMCID: PMC4048550 DOI: 10.1038/sj.npp.1300786] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The concurrent use of cocaine and opiate combinations (speedball) has increased since the 1970s and now represents a growing subset of intravenous drug abusers. An isobolographic analysis was applied to the ascending limb of the dose-effect curves for rat self-administration of cocaine, heroin, and their combination to determine the nature of the interaction. The addition of heroin to cocaine shifted the dose-effect curve for self-administration to the left, and the modulation in reinforcing efficacy of the combination of cocaine and heroin was found to be additive. A second experiment used microdialysis to determine the effects of this drug combination on nucleus accumbens (NAc) extracellular levels of dopamine ([DA](e)) in rats self-administering low doses of cocaine, heroin, or cocaine/heroin combinations. These doses of cocaine and cocaine/heroin combinations significantly increased NAc [DA](e), while heroin alone did not. The ratio of the % baseline of [DA](e) (or the dialysate concentrations of DA) to cocaine in the dialysate was higher during self-administration of cocaine/heroin combinations than with cocaine alone. These data indicate that although the interaction between cocaine and heroin in maintaining self-administration is additive, a potentiation of NAc dopaminergic neurotransmission is present, suggesting that NAc [DA](e) may not be a direct measure of reinforcing efficacy and/or it is not central to the mediation of the self-administration of this drug combination.
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Affiliation(s)
- James E Smith
- Center for the Neurobiological Investigation of Drug Abuse, Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Wake Forest University, Winston-Salem, NC, USA.
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Hemby SE, Horman B, Tang W. Differential regulation of ionotropic glutamate receptor subunits following cocaine self-administration. Brain Res 2005; 1064:75-82. [PMID: 16277980 PMCID: PMC3843347 DOI: 10.1016/j.brainres.2005.09.051] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2005] [Revised: 09/28/2005] [Accepted: 09/30/2005] [Indexed: 11/22/2022]
Abstract
Previous examination of binge cocaine self-administration and 2 week withdrawal from cocaine self-administration on ionotropic glutamate receptor subunit (iGluRs) protein levels revealed significant alterations in iGluR protein levels that differed between the mesocorticolimbic and nigrostriatal pathways. The present study was undertaken to extend the examination of cocaine-induced alterations in iGluR protein expression by assessing the effects of acute withdrawal (15-16 h) from limited access cocaine self-administration (8 h/day, 15 days). Western blotting was used to compare levels of iGluR protein expression (NR1-3B, GluR1-7, KA2) in the mesolimbic (ventral tegmental area, VTA; nucleus accumbens, NAc; and prefrontal cortex, PFC) and nigrostriatal pathways (substantia nigra, SN and dorsal caudate-putamen, CPu). Within the mesolimbic pathway, reductions were observed in NR1 and GluR5 immunoreactivity in the VTA although no significant alterations were observed in any iGluR subunits in the NAc. In the PFC, NR1 was significantly upregulated while GluR2/3, GluR4, GluR5, GluR6/7, and KA2 were decreased. Within the nigrostriatal pathway, NR1, NR2A, NR2B, GluR1, GluR6/7 and KA2 were increased in the dorsal CPu, whereas no significant changes were observed in the SN. The results demonstrate region- and pathway-specific alterations in iGluR subunit expression following limited cocaine self-administration and suggest the importance for the activation of pathways that are substrates of the reinforcing and motoric effects of cocaine.
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Affiliation(s)
- Scott E Hemby
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC 27101, USA.
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Verkuyl JM, Hemby SE, Joëls M. Chronic stress attenuates GABAergic inhibition and alters gene expression of parvocellular neurons in rat hypothalamus. Eur J Neurosci 2004; 20:1665-73. [PMID: 15355334 DOI: 10.1111/j.1460-9568.2004.03568.x] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Chronic stress causes disinhibition of the hypothalamus-pituitary-adrenal axis. Consequently, the brain is overexposed to glucocorticoids which in humans may precipitate stress-related disorders, e.g. depression. The hypothalamus-pituitary-adrenal activity is strongly regulated by GABAergic input to parvocellular neurons in the hypothalamic paraventricular nucleus. We here report a reduced frequency of miniature inhibitory postsynaptic currents (mIPSCs) in parvocellular neurons of rats exposed to 3 weeks of unpredictable stress. The mIPSC amplitude and kinetic properties were unchanged, pointing to a presynaptic change caused by chronic stress. Because paired-pulse inhibition was unaffected by chronic stress, the number of functional GABAergic synaptic contacts rather than the release probability seems to be reduced after chronic stress. Linearly amplified RNA from postsynaptic cells was hybridized with multiple cDNA clones of interest, including most GABA(A) receptor subunits. In agreement with the electrophysiological observations, relative expression of the prevalent GABA(A)alpha1, alpha3, gamma1 and gamma2 receptor subunits, which largely contribute to the recorded responses, was not altered after chronic stress. However, expression of the extra-synaptic GABA(A)alpha5 subunit, earlier linked to depression in humans, and of the delta receptor subunit were found to be significantly changed. In conclusion, chronic stress leads to presynaptic functional alterations in GABAergic input to the paraventricular nucleus which could contribute to the observed disinhibition of the hypothalamus-pituitary-adrenal axis; additionally other aspects of GABAergic transmission may also be changed due to transcriptional regulation of specific receptor subunits in the parvocellular neurons.
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MESH Headings
- 6-Cyano-7-nitroquinoxaline-2,3-dione/pharmacology
- Animals
- Blotting, Northern/methods
- Body Weight/physiology
- Chronic Disease
- Dose-Response Relationship, Radiation
- Electric Stimulation/methods
- Excitatory Amino Acid Agonists/pharmacology
- Excitatory Amino Acid Antagonists/pharmacology
- Gene Expression/physiology
- Hypothalamus/cytology
- In Vitro Techniques
- Male
- Membrane Potentials/drug effects
- Membrane Potentials/radiation effects
- N-Methylaspartate/pharmacology
- Neural Inhibition/physiology
- Neurons/metabolism
- Organ Size/physiology
- Patch-Clamp Techniques/methods
- RNA, Messenger/biosynthesis
- Rats
- Rats, Wistar
- Receptors, GABA/classification
- Receptors, GABA/genetics
- Receptors, GABA/metabolism
- Reverse Transcriptase Polymerase Chain Reaction/methods
- Stress, Physiological/metabolism
- Stress, Physiological/physiopathology
- Time Factors
- alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid/pharmacology
- gamma-Aminobutyric Acid/metabolism
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Affiliation(s)
- J Martin Verkuyl
- Swammerdam Institute for Life Sciences, Neurobiology section, Kruislaan 320, 1098 SM Amsterdam, The Netherlands
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Abstract
Chronic opiate administration induces a number of biochemical alterations within the mesolimbic dopamine system that may mediate various aspects of the addictive process. In the present study, rats were administered morphine (1.0 mg/infusion) for 20 days (17.6+/-3.0 infusions/day) based on infusion histories of self-administering rats. Calbindin-D28K immunoreactive neurons were microdissected from the nucleus accumbens (NAc) shell and core subregions and gene expression was assessed using cDNA macroarrays. Comparison of gene expression between the shell and core subregions of vehicle-treated rats revealed significantly higher relative abundance of GABA-A alpha1, Galphai2 and post-synaptic density protein 95 transcript (PSD-95) mRNA levels in the shell, whereas Ggamma2 and synuclein 1 were more abundant in the core of the NAc. In the NAc shell, morphine administration resulted in upregulation of caspace 9, NF-kappaB, NF-H, tau, GABA-A delta subunit, FGFR1, Ggamma2, synuclein 1, syntaxin 5 and 13, GRK5, and c-fos mRNAs. Caspace 1, D2 dopamine receptor, GABA-A alpha1 subunit, GRIA 1/3/4, Galphai2, PSD-95 and CREB were down-regulated in the NAc shell with morphine administration. In the core, neuronal apoptotic inhibitory protein (NAIP), GABA-A alpha1 subunit, GRIN2C, GRIA1, mGluR1, D4 dopamine receptor and PSD-95 were upregulated by morphine administration whereas bax, bcl-x, cox-1 and MAP2 were decreased. These data demonstrate that morphine administration alters gene expression differentially in NAc subregions. Specifically, GABA-A alpha1 subunit, GRIA1 subunit and PSD-95 mRNAs were decreased in the shell but increased in the core following morphine administration. In addition, these results provide potential targets for further evaluation in models of morphine reinforcement as well as novel mechanisms of action in morphine-induced pathophysiology.
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Affiliation(s)
- S E Hemby
- Departments of Pharmacology and Psychiatry and Behavioral Sciences, Yerkes National Primate Research Center, Neuroscience Division, Emory University School of Medicine, 954 Gatewood Road, Atlanta, GA 30329, USA.
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Abstract
As the technology of proteomics moves from a theoretical approach to a practical reality, neuroscientists will have to determine the most appropriate applications for this technology. Neuroscientists will have to surmount difficulties particular to their research, such as limited sample amounts, heterogeneous cellular compositions in samples, and the fact that many proteins of interest are rare, hydrophobic proteins. This review examines protein isolation and protein fractionation and separation using two-dimensional electrophoresis (2-DE) and mass spectrometry proteomic methods. Methods for quantifying relative protein expression between samples (e.g., 2-DIGE, and ICAT) are also described. The coverage of the proteome, ability to detect membrane proteins, resource requirements, and quantitative reliability of different approaches is also discussed. Although there are many challenges in proteomic neuroscience, this field promises many rewards in the future.
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Affiliation(s)
- Willard M. Freeman
- Departments of Pharmacology and Psychiatry & Behavioral Sciences, Yerkes National Primate Research Center, Neuroscience Division, Emory University School of Medicine, Atlanta, Georgia
| | - Scott E. Hemby
- Departments of Pharmacology and Psychiatry & Behavioral Sciences, Yerkes National Primate Research Center, Neuroscience Division, Emory University School of Medicine, Atlanta, Georgia
- Address reprint requests to: Scott E. Hemby, Yerkes National Primate Research Center, 954 Gatewood Road, Atlanta, Georgia 30329.
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Tang W, Wesley M, Freeman WM, Liang B, Hemby SE. Alterations in ionotropic glutamate receptor subunits during binge cocaine self-administration and withdrawal in rats. J Neurochem 2004; 89:1021-33. [PMID: 15140200 PMCID: PMC3843358 DOI: 10.1111/j.1471-4159.2004.02392.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Chronic cocaine use in humans and animal models is known to lead to pronounced alterations in glutamatergic function in brain regions associated with reinforcement. Previous studies have examined ionotropic glutamate receptor (iGluR) subunit protein level changes following acute and chronic experimenter-administered cocaine or after withdrawal periods from experimenter-administered cocaine. To evaluate whether alterations in expression of iGluRs are associated with cocaine reinforcement, protein levels were assessed after binge (8 h/day, 15 days; 24-h access, days 16-21) cocaine self-administration and following 2 weeks of abstinence from this binge. Western blotting was used to compare levels of iGluR protein expression (NR1-3B, GluR1-7, KA2) in the ventral tegmental area (VTA), substantia nigra (SN), nucleus accumbens (NAc), striatum and prefrontal cortex (PFC) of rats. iGluR subunits were altered in a time-dependent manner in all brain regions studied; however, selective alterations in certain iGluR subtypes appeared to be associated with binge cocaine self-administration and withdrawal in a region-specific manner. In the SN and VTA, alterations in iGluR protein levels compared with controls occurred only following binge access, whereas in the striatum and PFC, iGluR alterations occurred with binge access and following withdrawal. In the NAc, GluR2/3 levels were increased following withdrawal compared with binge access, and were the only changes observed in this region. Because subunit composition determines the functional properties of iGluRs, the observed changes may indicate alterations in the excitability of dopamine transmission underlying long-term biochemical and behavioral effects of cocaine.
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Affiliation(s)
- Wenxue Tang
- Department of Pharmacology, Yerkes National Primate Research Center, Neuroscience Division, Emory University School of Medicine, Atlanta, Georgia 30329, USA
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Ginsberg SD, Elarova I, Ruben M, Tan F, Counts SE, Eberwine JH, Trojanowski JQ, Hemby SE, Mufson EJ, Che S. Single-Cell Gene Expression Analysis: Implications for Neurodegenerative and Neuropsychiatric Disorders. Neurochem Res 2004; 29:1053-64. [PMID: 15176463 DOI: 10.1023/b:nere.0000023593.77052.f7] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Technical and experimental advances in microaspiration techniques, RNA amplification, quantitative real-time polymerase chain reaction (qPCR), and cDNA microarray analysis have led to an increase in the number of studies of single-cell gene expression. In particular, the central nervous system (CNS) is an ideal structure to apply single-cell gene expression paradigms. Unlike an organ that is composed of one principal cell type, the brain contains a constellation of neuronal and noneuronal populations of cells. A goal is to sample gene expression from similar cell types within a defined region without potential contamination by expression profiles of adjacent neuronal subpopulations and noneuronal cells. The unprecedented resolution afforded by single-cell RNA analysis in combination with cDNA microarrays and qPCR-based analyses allows for relative gene expression level comparisons across cell types under different experimental conditions and disease states. The ability to analyze single cells is an important distinction from global and regional assessments of mRNA expression and can be applied to optimally prepared tissues from animal models as well as postmortem human brain tissues. This focused review illustrates the potential power of single-cell gene expression studies within the CNS in relation to neurodegenerative and neuropsychiatric disorders such as Alzheimer's disease (AD) and schizophrenia, respectively.
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Affiliation(s)
- Stephen D Ginsberg
- Center for Dementia Research, Nathan Kline Institute, New York University School of Medicine, Orangeburg, New York 10962, USA.
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Backes E, Hemby SE. Discrete cell gene profiling of ventral tegmental dopamine neurons after acute and chronic cocaine self-administration. J Pharmacol Exp Ther 2003; 307:450-9. [PMID: 12966149 PMCID: PMC4048547 DOI: 10.1124/jpet.103.054965] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Chronic cocaine administration induces a number of biochemical alterations within the mesolimbic dopamine system that may mediate various aspects of the addictive process such as sensitization, craving, withdrawal, and relapse. In the present study, rats were allowed to self-administer cocaine (0.5 mg/infusion) for 1 or 20 days. Tyrosine hydroxylase immunopositive cells were microdissected from the ventral tegmental area (VTA) using laser capture microdissection, and changes in the abundances of 95 mRNAs were assessed using cDNA macroarrays. Five GABA-A receptor subunit mRNAs (alpha4, alpha6, beta2, gamma2, and delta) were down-regulated at both 1 and 20 days of cocaine self-administration. In contrast, the catalytic subunit of protein phosphatase 2A (PP2alpha), GABA-A alpha1, and Galphai2 were significantly increased at both time points. Additionally, calcium/calmodulin-dependent protein kinase IIalpha mRNA levels were increased initially followed by a slight decrease after 20 days, whereas neuronal nitric-oxide synthase mRNA levels were initially decreased but returned to near control levels by day 20. These results indicate that alterations of specific GABA-A receptor subtypes and other signal transduction transcripts seem to be specific neuroadaptations associated with cocaine self-administration. Moreover, as subunit composition determines the functional properties of GABA-A receptors, the observed changes may indicate alterations in the excitability of dopamine transmission underlying long-term biochemical and behavioral effects of cocaine.
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Affiliation(s)
- Eric Backes
- Department of Pharmacology, Neuroscience Division, Emory University School of Medicine, Atlanta, GA, USA
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45
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Abstract
Antipsychotic drugs require a treatment regimen of several weeks before clinical efficacy is achieved in patient populations. While the biochemical mechanisms underlying the delayed temporal profile remain unclear, molecular adaptations in specific neuroanatomical loci are likely involved. Haloperidol-induced changes in gene expression in various brain regions have been observed; however, alterations in distinct neuronal populations have remained elusive. The present study examined changes in gene expression profiles of ventral tegmental area (VTA) and substantia nigra (SN) tyrosine hydroxylase immunopositive neurons following 1, 10 or 21 days of haloperidol administration (0.5 mg/kg/day). Macroarrays were used to study the expression of receptors, signaling proteins, transcription factors and pre- and post-synaptic proteins. Data were analyzed using conventional statistical procedures as well as self-organizing maps (SOM) to elucidate conserved patterns of expression changes. Results show statistically significant haloperidol-induced and time-dependent alterations in 17 genes in the VTA and 25 genes in the SN, including glutamate and GABA receptor subunits, signaling proteins and transcription factors. SOMs revealed distinct patterns of gene expression changes in response to haloperidol. Understanding how gene expression is altered over a clinically relevant time course of haloperidol administration may provide insight into the development of antipsychotic efficacy as well as the underlying pathology of schizophrenia.
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Affiliation(s)
- Wendy H Fasulo
- Department of Pharmacology, Yerkes National Primate Research Center, Neuroscience Division, Emory University School of Medicine, Atlanta, GA, USA
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46
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Abstract
Chronic cocaine use in humans and animal models is known to lead to pronounced alterations in neuronal function in brain regions associated with drug reinforcement. To evaluate whether the alterations in gene expression in cocaine overdose victims are associated with specific dopamine populations in the midbrain, cDNA arrays and western blotting were used to compare gene and protein expression patterns between cocaine overdose victims and age-matched controls in the ventral tegmental area (VTA) and lateral substantia nigra (l-SN). Array analysis revealed significant up-regulation of numerous transcripts in the VTA, but not in the l-SN, of cocaine overdose victims including NMDAR1, GluR2, GluR5 and KA2 receptor mRNA (p < 0.05). No significant alterations between overdose victims and controls were observed for GluR1, R3 or R4 mRNA levels. Correspondingly, western blot analysis revealed VTA-selective up-regulation of CREB (p < 0.01), NMDAR1 (p < 0.01), GluR2 (p < 0.05), GluR5 (p < 0.01) and KA2 (p < 0.05) protein levels of cocaine overdose victims. The present results indicate that selective alterations of CREB and certain ionotropic glutamate receptor (iGluR) subtypes appear to be associated with chronic cocaine use in humans in a region-specific manner. Moreover, as subunit composition determines the functional properties of iGluRs, the observed changes may indicate alterations in the excitability of dopamine transmission underlying long-term biochemical and behavioral effects of cocaine in humans.
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Affiliation(s)
- Wen-Xue Tang
- Department of Pharmacology and Psychiatry/Behavioral Sciences, Yerkes National Primate Research Center, Neuroscience Division, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Wendy H. Fasulo
- Department of Pharmacology and Psychiatry/Behavioral Sciences, Yerkes National Primate Research Center, Neuroscience Division, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Deborah C. Mash
- Department of Neurology and Molecular and Cellular Pharmacology, University of Miami School of Medicine, Miami, Florida, USA
| | - Scott E. Hemby
- Department of Pharmacology and Psychiatry/Behavioral Sciences, Yerkes National Primate Research Center, Neuroscience Division, Emory University School of Medicine, Atlanta, Georgia, USA
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47
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Abstract
Age-related decline in dopamine receptor levels has been observed in regional studies of animal and human brains; however, identifying specific cellular substrates and/or alterations in distinct neuronal populations remains elusive. To evaluate whether age-related decreases in dopamine receptor subtypes are associated with specific cell populations in the hippocampus and entorhinal cortex, antisense RNA amplification was combined with cDNA array analysis to examine effects of aging on D1-D5 dopamine receptor mRNA expression levels in hippocampal CA1 pyramidal neurons and entorhinal cortex layer II stellate cells from post-mortem human brains (19-92 years). In CA1 pyramidal neurons, significant age-related decline was observed for dopamine receptor mRNAs (D1-D4, P < 0.001; D5, P < 0.05) but not for the cytoskeletal elements beta-actin, three-repeat (3R) tau, and four-repeat (4R) tau. In contrast, no significant changes were observed in stellate cells across the same cohort. Thus, senescence may be a factor responsible for cell-specific decrements in dopamine receptor gene expression in one population of neurons within a circuit that is critical for learning and memory. Furthermore, these results support the hypothesis that alterations in dopaminergic function may also be related to behavioral abnormalities, such as psychosis, that occur with aging.
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Affiliation(s)
- Scott E Hemby
- Department of Pharmacology and Psychiatry/Behavioral Sciences, Yerkes National Primate Research Center, Neuroscience Division, Emory University School of Medicine, Atlanta, Georgia 30329, USA.
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48
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Hemby SE, Ginsberg SD, Brunk B, Arnold SE, Trojanowski JQ, Eberwine JH. Gene expression profile for schizophrenia: discrete neuron transcription patterns in the entorhinal cortex. Arch Gen Psychiatry 2002; 59:631-40. [PMID: 12090816 DOI: 10.1001/archpsyc.59.7.631] [Citation(s) in RCA: 203] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
BACKGROUND Several lines of evidence indicate the altered function of the temporal lobe, including the hippocampus and entorhinal cortex (EC), is associated with schizophrenia. We used single-cell gene expression technologies to assess coordinate changes in the expression of multiple genes, including neuronal signaling and synaptic-related markers in EC layer II stellate neurons. METHODS We used a single-neuron microdissection technique coupled with linear antisense RNA amplification and high density/candidate gene arrays to assess coordinate changes in gene expression. The expression and relative abundance of more than 18,000 messenger RNAs were assessed from EC layer II stellate neurons from postmortem samples of schizophrenic and age-matched control brains. Results of this initial screen were used to perform a more specific secondary messenger RNA screen for each subject. RESULTS Data disclosed marked differences in expression of various G-protein-coupled receptor-signaling transcripts, glutamate receptor subunits, synaptic proteins, and other transcripts. Results of secondary screening showed significant decreases in levels of G-protein subunit i(alpha)1, glutamate receptor 3, N-methyl-D-aspartate receptor 1, synaptophysin, and sensory nerve action potentials 23 and 25 in the stellate neurons of schizophrenic patients. We observed down-regulation of phospholemman (a phosphoprotein associated with anion channel formation) messenger RNA and protein levels in layer II/III stellate neurons in the population with schizophrenia. CONCLUSIONS These results provide a preliminary expression profile of schizophrenia in defined neuronal populations. Understanding the coordinated involvement of multiple genes in human disease provides insight into the molecular basis of the disease and offers new targets for pharmacotherapeutic intervention.
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Affiliation(s)
- Scott E Hemby
- Department of Pharmacology, Yerkes Regional Primate Research Center, Neuroscience Division, Emory University School of Medicine, Atlanta, GA, USA
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Affiliation(s)
| | - Scott E. Hemby
- Corresponding author: Yerkes Regional Primate Center 954 Gatewood Road, NE Atlanta, GA 30329 Telephone: (404) 727-5988 Fax: (404) 727-8756
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Abstract
Several studies indicate a primary dysfunction of the temporal lobe in autism, specifically the hippocampal formation and entorhinal cortex (EC). Assessment of gene expression in the EC and hippocampus will provide insight into the subtle alterations in neuronal function associated with autism. To this end, evaluations in a primate model of social attachment, which produces behaviors associated with autism, in addition to the use of human post-mortem tissue from individuals diagnosed with autism will provide heretofore unattainable information of how the complex neural circuitry of this region is altered in autism. Identification of altered expression of multiple genes should provide a molecular "fingerprint" of autism and may provide new targets for pharmacotherapeutic intervention.
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Affiliation(s)
- S E Hemby
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia 30329, USA.
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