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Borzou A, Miller SN, Hommel JD, Schwarz JM. Cocaine diminishes functional network robustness and destabilizes the energy landscape of neuronal activity in the medial prefrontal cortex. PNAS NEXUS 2024; 3:pgae092. [PMID: 38476665 PMCID: PMC10929585 DOI: 10.1093/pnasnexus/pgae092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 02/13/2024] [Indexed: 03/14/2024]
Abstract
We present analysis of neuronal activity recordings from a subset of neurons in the medial prefrontal cortex of rats before and after the administration of cocaine. Using an underlying modern Hopfield model as a description for the neuronal network, combined with a machine learning approach, we compute the underlying functional connectivity of the neuronal network. We find that the functional connectivity changes after the administration of cocaine with both functional-excitatory and functional-inhibitory neurons being affected. Using conventional network analysis, we find that the diameter of the graph, or the shortest length between the two most distant nodes, increases with cocaine, suggesting that the neuronal network is less robust. We also find that the betweenness centrality scores for several of the functional-excitatory and functional-inhibitory neurons decrease significantly, while other scores remain essentially unchanged, to also suggest that the neuronal network is less robust. Finally, we study the distribution of neuronal activity and relate it to energy to find that cocaine drives the neuronal network towards destabilization in the energy landscape of neuronal activation. While this destabilization is presumably temporary given one administration of cocaine, perhaps this initial destabilization indicates a transition towards a new stable state with repeated cocaine administration. However, such analyses are useful more generally to understand how neuronal networks respond to perturbations.
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Affiliation(s)
- Ahmad Borzou
- Department of Physics and BioInspired Institute, Syracuse University, Syracuse, NY 13244, USA
- CompuFlair, Houston, TX 77064, USA
| | - Sierra N Miller
- Department of Pharmacology and Toxicology, Center for Addiction Sciences and Therapeutics, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Jonathan D Hommel
- Department of Pharmacology and Toxicology, Center for Addiction Sciences and Therapeutics, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - J M Schwarz
- Department of Physics and BioInspired Institute, Syracuse University, Syracuse, NY 13244, USA
- Indian Creek Farm, Ithaca, NY 14850, USA
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2
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Hsu LM, Cerri DH, Lee SH, Shnitko TA, Carelli RM, Shih YYI. Intrinsic Functional Connectivity between the Anterior Insular and Retrosplenial Cortex as a Moderator and Consequence of Cocaine Self-Administration in Rats. J Neurosci 2024; 44:e1452232023. [PMID: 38233216 PMCID: PMC10869158 DOI: 10.1523/jneurosci.1452-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 12/21/2023] [Accepted: 12/22/2023] [Indexed: 01/19/2024] Open
Abstract
While functional brain imaging studies in humans suggest that chronic cocaine use alters functional connectivity (FC) within and between key large-scale brain networks, including the default mode network (DMN), the salience network (SN), and the central executive network (CEN), cross-sectional studies in humans are challenging to obtain brain FC prior to cocaine use. Such information is critical to reveal the relationship between individual's brain FC and the subsequent development of cocaine dependence and brain changes during abstinence. Here, we performed a longitudinal study examining functional magnetic resonance imaging (fMRI) data in male rats (n = 7), acquired before cocaine self-administration (baseline), on 1 d of abstinence following 10 d of cocaine self-administration, and again after 30 d of experimenter-imposed abstinence. Using repeated-measures analysis of variance (ANOVA) with network-based statistics (NBS), significant connectivity changes were found between anterior insular cortex (AI) of the SN, retrosplenial cortex (RSC) of the DMN, somatosensory cortex, and caudate-putamen (CPu), with AI-RSC FC showing the most robust changes between baseline and 1 d of abstinence. Additionally, the level of escalated cocaine intake is associated with AI-RSC and AI-CPu FC changes between 1 d and 30 d of abstinence; further, the subjects' AI-RSC FC prior to cocaine intake is a significant moderator for the AI-RSC changes during abstinence. These results provide novel insights into the roles of AI-RSC FC before and after cocaine intake and suggest this circuit to be a potential target to modulate large-scale network and associated behavioral changes in cocaine use disorders.
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Affiliation(s)
- Li-Ming Hsu
- Center for Animal Magnetic Resonance Imaging, The University of North Carolina at Chapel Hill, Chapel Hill 27599, North Carolina
- Biomedical Research Imaging Center, The University of North Carolina at Chapel Hill, Chapel Hill 27599, North Carolina
- Departments of Neurology, The University of North Carolina at Chapel Hill, Chapel Hill 27599, North Carolina
| | - Domenic H Cerri
- Center for Animal Magnetic Resonance Imaging, The University of North Carolina at Chapel Hill, Chapel Hill 27599, North Carolina
- Biomedical Research Imaging Center, The University of North Carolina at Chapel Hill, Chapel Hill 27599, North Carolina
- Departments of Neurology, The University of North Carolina at Chapel Hill, Chapel Hill 27599, North Carolina
| | - Sung-Ho Lee
- Center for Animal Magnetic Resonance Imaging, The University of North Carolina at Chapel Hill, Chapel Hill 27599, North Carolina
- Biomedical Research Imaging Center, The University of North Carolina at Chapel Hill, Chapel Hill 27599, North Carolina
- Departments of Neurology, The University of North Carolina at Chapel Hill, Chapel Hill 27599, North Carolina
| | - Tatiana A Shnitko
- Center for Animal Magnetic Resonance Imaging, The University of North Carolina at Chapel Hill, Chapel Hill 27599, North Carolina
- Biomedical Research Imaging Center, The University of North Carolina at Chapel Hill, Chapel Hill 27599, North Carolina
- Departments of Neurology, The University of North Carolina at Chapel Hill, Chapel Hill 27599, North Carolina
| | - Regina M Carelli
- Psychology and Neuroscience, The University of North Carolina at Chapel Hill, Chapel Hill 27599, North Carolina
| | - Yen-Yu Ian Shih
- Center for Animal Magnetic Resonance Imaging, The University of North Carolina at Chapel Hill, Chapel Hill 27599, North Carolina
- Biomedical Research Imaging Center, The University of North Carolina at Chapel Hill, Chapel Hill 27599, North Carolina
- Departments of Neurology, The University of North Carolina at Chapel Hill, Chapel Hill 27599, North Carolina
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3
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Nett KE, LaLumiere RT. Infralimbic cortex functioning across motivated behaviors: Can the differences be reconciled? Neurosci Biobehav Rev 2021; 131:704-721. [PMID: 34624366 PMCID: PMC8642304 DOI: 10.1016/j.neubiorev.2021.10.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Revised: 09/10/2021] [Accepted: 10/02/2021] [Indexed: 10/20/2022]
Abstract
The rodent infralimbic cortex (IL) is implicated in higher order executive functions such as reward seeking and flexible decision making. However, the precise nature of its role in these processes is unclear. Early evidence indicated that the IL promotes the extinction and ongoing inhibition of fear conditioning and cocaine seeking. However, evidence spanning other behavioral domains, such as natural reward seeking and habit-based learning, suggests a more nuanced understanding of IL function. As techniques have advanced and more studies have examined IL function, identifying a unifying explanation for its behavioral function has become increasingly difficult. Here, we discuss evidence of IL function across motivated behaviors, including associative learning, drug seeking, natural reward seeking, and goal-directed versus habit-based behaviors, and emphasize how context-specific encoding and heterogeneous IL neuronal populations may underlie seemingly conflicting findings in the literature. Together, the evidence suggests that a major IL function is to facilitate the encoding and updating of contingencies between cues and behaviors to guide subsequent behaviors.
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Affiliation(s)
- Kelle E Nett
- Interdisciplinary Neuroscience Program, University of Iowa, Iowa City, IA 52242, United States.
| | - Ryan T LaLumiere
- Interdisciplinary Neuroscience Program, University of Iowa, Iowa City, IA 52242, United States; Department of Psychological and Brain Sciences, University of Iowa, Iowa City, IA 52242, United States; Iowa Neuroscience Institute, University of Iowa, Iowa City, IA 52242, United States
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Saad L, Kalsbeek A, Zwiller J, Anglard P. Rhythmic Regulation of DNA Methylation Factors and Core-Clock Genes in Brain Structures Activated by Cocaine or Sucrose: Potential Role of Chromatin Remodeling. Genes (Basel) 2021; 12:genes12081195. [PMID: 34440369 PMCID: PMC8392220 DOI: 10.3390/genes12081195] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 07/28/2021] [Accepted: 07/29/2021] [Indexed: 12/25/2022] Open
Abstract
The circadian system interacts with the mesocorticolimbic reward system to modulate reward and memory in a time-of-day dependent manner. The circadian discrimination of reward, however, remains difficult to address between natural reinforcers and drugs of abuse. Circadian rhythms control cocaine sensitization and conversely cocaine causes long-term alteration in circadian periodicity in part through the serotonergic neurotransmission. Since neural circuits activated by cocaine and natural reinforcers do not completely overlap, we compared the effect of cocaine with that of sucrose, a strong reinforcer in rodents, by using passive chronic administration. The expression of fifteen genes playing a major role in DNA methylation (Dnmts, Tets), circadian rhythms (Clock, Bmal1, Per1/2, Cry1/2, Rev-Erbβ, Dbp1), appetite, and satiety (Orexin, Npy) was analyzed in dopamine projection areas like the prefrontal cortex, the caudate putamen, and the hypothalamus interconnected with the reward system. The corresponding proteins of two genes (Orexin, Per2) were examined by IHC. For many factors controlling biological and cognitive functions, striking opposite responses were found between the two reinforcers, notably for genes controlling DNA methylation/demethylation processes and in global DNA methylation involved in chromatin remodeling. The data are consistent with a repression of critical core-clock genes by cocaine, suggesting that, consequently, both agents differentially modulate day/night cycles. Whether observed cocaine and sucrose-induced changes in DNA methylation in a time dependent manner are long lasting or contribute to the establishment of addiction requires further neuroepigenetic investigation. Understanding the mechanisms dissociating drugs of abuse from natural reinforcers remains a prerequisite for the design of selective therapeutic tools for compulsive behaviors.
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Affiliation(s)
- Lamis Saad
- Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), UMR 7364 CNRS, Université de Strasbourg, Neuropôle de Strasbourg, 67000 Strasbourg, France; (L.S.); (J.Z.)
- The Netherlands Institute for Neuroscience (NIN), Royal Netherlands Academy of Arts and Sciences (KNAW), 1105 BA Amsterdam, The Netherlands
- Department of Endocrinology and Metabolism, Amsterdam UMC, University of Amsterdam, 1066 EA Amsterdam, The Netherlands
| | - Andries Kalsbeek
- The Netherlands Institute for Neuroscience (NIN), Royal Netherlands Academy of Arts and Sciences (KNAW), 1105 BA Amsterdam, The Netherlands
- Department of Endocrinology and Metabolism, Amsterdam UMC, University of Amsterdam, 1066 EA Amsterdam, The Netherlands
- Correspondence: (A.K.); or (P.A.)
| | - Jean Zwiller
- Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), UMR 7364 CNRS, Université de Strasbourg, Neuropôle de Strasbourg, 67000 Strasbourg, France; (L.S.); (J.Z.)
- CNRS, Centre National de la Recherche Scientifique, 75016 Paris, France
| | - Patrick Anglard
- Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), UMR 7364 CNRS, Université de Strasbourg, Neuropôle de Strasbourg, 67000 Strasbourg, France; (L.S.); (J.Z.)
- INSERM, Institut National de la Santé et de la Recherche Médicale, 75013 Paris, France
- Correspondence: (A.K.); or (P.A.)
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Saad L, Sartori M, Pol Bodetto S, Romieu P, Kalsbeek A, Zwiller J, Anglard P. Regulation of Brain DNA Methylation Factors and of the Orexinergic System by Cocaine and Food Self-Administration. Mol Neurobiol 2019; 56:5315-5331. [PMID: 30603957 DOI: 10.1007/s12035-018-1453-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 12/07/2018] [Indexed: 12/22/2022]
Abstract
Inhibitors of DNA methylation and orexin type-1 receptor antagonists modulate the neurobiological effects driving drugs of abuse and natural reinforcers by activating common brain structures of the mesolimbic reward system. In this study, we applied a self-administration paradigm to assess the involvement of factors regulating DNA methylation processes and satiety or appetite signals. These factors include Dnmts and Tets, miR-212/132, orexins, and orx-R1 genes. The study focused on dopamine projection areas such as the prefrontal cortex (PFCx) and caudate putamen (CPu) and in the hypothalamus (HP) that is interconnected with the reward system. Striking changes were observed in response to both reinforcers, but differed depending on contingent and non-contingent delivery. Expression also differed in the PFCx and the CPu. Cocaine and food induced opposite effects on Dnmt3a expression in both brain structures, whereas they repressed both miRs to a different extent, without affecting their primary transcript in the CPu. Unexpectedly, orexin mRNAs were found in the CPu, suggesting a transport from their transcription site in the HP. The orexin receptor1 gene was found to be induced by cocaine in the PFCx, consistent with a regulation by DNA methylation. Global levels of 5-methylcytosines in the PFCx were not significantly altered by cocaine, suggesting that it is rather their distribution that contributes to long-lasting behaviors. Together, our data demonstrate that DNA methylation regulating factors are differentially altered by cocaine and food. At the molecular level, they support the idea that neural circuits activated by both reinforcers do not completely overlap.
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Affiliation(s)
- Lamis Saad
- Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), UMR 7364 CNRS, Neuropôle de Strasbourg, Université de Strasbourg, Strasbourg, France
- The Netherlands Institute for Neuroscience (NIN), Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, The Netherlands
| | - Maxime Sartori
- Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), UMR 7364 CNRS, Neuropôle de Strasbourg, Université de Strasbourg, Strasbourg, France
- IGBMC, Inserm U 964, CNRS UMR 7104, University of Strasbourg, Illkirch, France
| | - Sarah Pol Bodetto
- Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), UMR 7364 CNRS, Neuropôle de Strasbourg, Université de Strasbourg, Strasbourg, France
| | - Pascal Romieu
- Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), UMR 7364 CNRS, Neuropôle de Strasbourg, Université de Strasbourg, Strasbourg, France
| | - Andries Kalsbeek
- The Netherlands Institute for Neuroscience (NIN), Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, The Netherlands
- Department of Endocrinology and Metabolism, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Jean Zwiller
- Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), UMR 7364 CNRS, Neuropôle de Strasbourg, Université de Strasbourg, Strasbourg, France
| | - Patrick Anglard
- Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), UMR 7364 CNRS, Neuropôle de Strasbourg, Université de Strasbourg, Strasbourg, France.
- INSERM, Institut National de la Santé et de la Recherche Médicale, Paris, France.
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Physiological Considerations of Functional Magnetic Resonance Imaging in Animal Models. BIOLOGICAL PSYCHIATRY: COGNITIVE NEUROSCIENCE AND NEUROIMAGING 2019; 4:522-532. [DOI: 10.1016/j.bpsc.2018.08.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 07/31/2018] [Accepted: 08/02/2018] [Indexed: 02/06/2023]
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7
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Allen CP, Park K, Li A, Volkow ND, Koob GF, Pan Y, Hu X, Du C. Enhanced neuronal and blunted hemodynamic reactivity to cocaine in the prefrontal cortex following extended cocaine access: optical imaging study in anesthetized rats. Addict Biol 2019; 24:485-497. [PMID: 29504647 DOI: 10.1111/adb.12615] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 01/22/2018] [Accepted: 01/26/2018] [Indexed: 12/24/2022]
Abstract
Cocaine addiction is associated with dysfunction of the prefrontal cortex (PFC), which facilitates relapse and compulsive drug taking. To assess if cocaine's effects on both neuronal and vascular activity contribute to PFC dysfunction, we used optical coherence tomography and multi-wavelength laser speckle to measure vascularization and hemodynamics and used GCaMP6f to monitor intracellular Ca2+ levels ([Ca2+ ]in ) as a marker of neuronal activity. Rats were given short (1 hour; ShA) or long (6 hours; LgA) access cocaine self-administration. As expected, LgA but not ShA rats escalated cocaine intake. In naïve rats, acute cocaine decreased oxygenated hemoglobin, increased deoxygenated hemoglobin and reduced cerebral blood flow in PFC, likely due to cocaine-induced vasoconstriction. ShA rats showed enhanced hemodynamic response and slower recovery after cocaine, versus naïve. LgA rats showed a blunted hemodynamic response, but an enhanced PFC neuronal [Ca2+ ]in increase after cocaine challenge associated with drug intake. Both ShA and LgA groups had higher vessel density, indicative of angiogenesis, presumably to compensate for cocaine's vasoconstricting effects. Cocaine self-administration modified the PFC cerebrovascular responses enhancing it in ShA and attenuating it in LgA animals. In contrast, LgA but not ShA animals showed sensitized neuronal reactivity to acute cocaine in the PFC. The opposite changes in hemodynamics (decreased) and neuronal responses (enhanced) in LgA rats indicate that these constitute distinct effects and suggest that the neuronal and not the vascular effects are associated with escalation of cocaine intake in addiction whereas its vascular effect in PFC might contribute to cognitive deficits that increase vulnerability to relapse.
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Affiliation(s)
- Craig P. Allen
- Department of Biomedical EngineeringStony Brook University Stony Brook NY USA
| | - Kicheon Park
- Department of Biomedical EngineeringStony Brook University Stony Brook NY USA
| | - Ang Li
- Department of Biomedical EngineeringStony Brook University Stony Brook NY USA
| | - Nora D. Volkow
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health Bethesda MD USA
| | - George F. Koob
- National Institute on Drug Abuse, National Institutes of Health Bethesda MD USA
| | - Yingtian Pan
- Department of Biomedical EngineeringStony Brook University Stony Brook NY USA
| | - Xiu‐Ti Hu
- Department of Immunology and MicrobiologyRush University Medical Center Chicago Il USA
| | - Congwu Du
- Department of Biomedical EngineeringStony Brook University Stony Brook NY USA
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Perez PD, Hall G, Zubcevic J, Febo M. Cocaine differentially affects synaptic activity in memory and midbrain areas of female and male rats: an in vivo MEMRI study. Brain Imaging Behav 2018; 12:201-216. [PMID: 28236167 DOI: 10.1007/s11682-017-9691-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Manganese enhanced magnetic resonance imaging (MEMRI) has been previously used to determine the effect of acute cocaine on calcium-dependent synaptic activity in male rats. However, there have been no MEMRI studies examining sex differences in the functional neural circuits affected by repeated cocaine. In the present study, we used MEMRI to investigate the effects of repeated cocaine on brain activation in female and male rats. Adult female and male rats were scanned at 4.7 Tesla three days after final treatment with saline, a single cocaine injection (15 mg kg-1, i.p. × 1 day) or repeated cocaine injections (15 mg kg-1, i.p. × 10 days). A day before imaging rats were provided with an i.p. injection of manganese chloride (70 mg kg-1). Cocaine produced effects on MEMRI activity that were dependent on sex. In females, we observed that a single cocaine injection reduced MEMRI activity in hippocampal CA3, ventral tegmental area (VTA), and median Raphé, whereas repeated cocaine increased MEMRI activity in dentate gyrus and interpeduncular nucleus. In males, repeated cocaine reduced MEMRI activity in VTA. Overall, it appeared that female rats showed a general trend towards increase MEMRI activity with single cocaine and reduced activity with repeated exposure, while male rats showed a trend towards opposite effects. Our results provide evidence for sex differences in the in vivo neural response to cocaine, which involves primarily hippocampal, amygdala and midbrain areas.
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Affiliation(s)
- Pablo D Perez
- Department of Psychiatry, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - Gabrielle Hall
- Department of Psychiatry, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - Jasenka Zubcevic
- Department of Physiological Sciences, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Marcelo Febo
- Department of Psychiatry, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL, 32610, USA.
- Center for Addiction Research and Education (CARE), University of Florida, Gainesville, FL, USA.
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9
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Non-imaged based method for matching brains in a common anatomical space for cellular imagery. J Neurosci Methods 2018; 304:136-145. [DOI: 10.1016/j.jneumeth.2018.04.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 04/06/2018] [Accepted: 04/07/2018] [Indexed: 11/18/2022]
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10
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Broadwater MA, Lee SH, Yu Y, Zhu H, Crews FT, Robinson DL, Shih YYI. Adolescent alcohol exposure decreases frontostriatal resting-state functional connectivity in adulthood. Addict Biol 2018; 23:810-823. [PMID: 28691248 PMCID: PMC5760482 DOI: 10.1111/adb.12530] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 05/18/2017] [Accepted: 05/23/2017] [Indexed: 12/11/2022]
Abstract
Connectivity of the prefrontal cortex (PFC) matures through adolescence, coinciding with emergence of adult executive function and top-down inhibitory control over behavior. Alcohol exposure during this critical period of brain maturation may affect development of PFC and frontolimbic connectivity. Adult rats exposed to adolescent intermittent ethanol (AIE; 5 g/kg ethanol, 25 percent v/v in water, intragastrically, 2-day-on, 2-day-off, postnatal day 25-54) or water control underwent resting-state functional MRI to test the hypothesis that AIE induces persistent changes in frontolimbic functional connectivity under baseline and acute alcohol conditions (2 g/kg ethanol or saline, intraperitoneally administered during scanning). Data were acquired on a Bruker 9.4-T MR scanner with rats under dexmedetomidine sedation in combination with isoflurane. Frontolimbic network regions-of-interest for data analysis included PFC [prelimbic (PrL), infralimbic (IL), and orbitofrontal cortex (OFC) portions], nucleus accumbens (NAc), caudate putamen (CPu), dorsal hippocampus, ventral tegmental area, amygdala, and somatosensory forelimb used as a control region. AIE decreased baseline resting-state connectivity between PFC subregions (PrL-IL and IL-OFC) and between PFC-striatal regions (PrL-NAc, IL-CPu, IL-NAc, OFC-CPu, and OFC-NAc). Acute ethanol induced negative blood-oxygen-level-dependent changes within all regions of interest examined, along with significant increases in functional connectivity in control, but not AIE animals. Together, these data support the hypothesis that binge-like adolescent alcohol exposure causes persistent decreases in baseline frontolimbic (particularly frontostriatal) connectivity and alters sensitivity to acute ethanol-induced increases in functional connectivity in adulthood.
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Affiliation(s)
| | - Sung-Ho Lee
- Department of Neurology, University of North Carolina, Chapel Hill, NC, USA
- Departments of Biomedical Research Imaging Center and Biomedical Engineering, University of North Carolina, Chapel Hill, NC, USA
| | - Yang Yu
- Department of Statistics and Operations, University of North Carolina, Chapel Hill, NC, USA
- Departments of Biomedical Research Imaging Center and Biomedical Engineering, University of North Carolina, Chapel Hill, NC, USA
| | - Hongtu Zhu
- Department of Biostatistics, University of North Carolina, Chapel Hill, NC, USA
- Departments of Biomedical Research Imaging Center and Biomedical Engineering, University of North Carolina, Chapel Hill, NC, USA
| | - Fulton T. Crews
- Bowles Center for Alcohol Studies, University of North Carolina, Chapel Hill, NC, USA
- Department of Pharmacology, School of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Donita L. Robinson
- Bowles Center for Alcohol Studies, University of North Carolina, Chapel Hill, NC, USA
- Department of Psychiatry, University of North Carolina, Chapel Hill, NC, USA
| | - Yen-Yu Ian Shih
- Department of Neurology, University of North Carolina, Chapel Hill, NC, USA
- Departments of Biomedical Research Imaging Center and Biomedical Engineering, University of North Carolina, Chapel Hill, NC, USA
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Brynildsen JK, Hsu LM, Ross TJ, Stein EA, Yang Y, Lu H. Physiological characterization of a robust survival rodent fMRI method. Magn Reson Imaging 2016; 35:54-60. [PMID: 27580522 DOI: 10.1016/j.mri.2016.08.010] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 08/13/2016] [Accepted: 08/20/2016] [Indexed: 10/21/2022]
Abstract
Anesthetics are commonly used in preclinical functional MRI studies. It is well-appreciated that proper choice of anesthetics is of critical importance for maintaining a physiologically normal range of autonomic functioning. A recent study, using a low dose of dexmedetomidine (active isomer of medetomidine) in combination with a low dose of isoflurane, suggested stable measurements across repeated fMRI experiments in individual animals with each session lasting up to several hours. The rat default mode network has been successfully identified using this preparation, indicating that this protocol minimally disturbs brain network functions. However, medetomidine is known to cause peripheral vasoconstriction, respiratory suppression, and bradycardia, each of which could independently confound the BOLD signal. The goal of this study was to systematically characterize physiological conditions for fMRI experiments under this anesthetic regimen. To this end, we acquired somatosensory stimulation "task-evoked" and resting-state fMRI to evaluate the integrity of neurovascular coupling and brain network function during three time windows (0-30min, 30-90min, and 90-150min) following dexmedetomidine initiation. Results demonstrate that both evoked BOLD response and resting-state fMRI signal remained stable during the 90-150min time window, while autonomic physiological parameters maintained near-normal conditions during this period. Our data suggest that using a spontaneously-inhaled, low dose of isoflurane in combination with a continuous low dose of dexmedetomidine is a viable option for longitudinal imaging studies in rats.
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Affiliation(s)
- Julia K Brynildsen
- Neuroimaging Research Branch, National Institute on Drug Abuse, Intramural Research Program, 251 Bayview Blvd, Suite 200, Baltimore, MD, USA
| | - Li-Ming Hsu
- Neuroimaging Research Branch, National Institute on Drug Abuse, Intramural Research Program, 251 Bayview Blvd, Suite 200, Baltimore, MD, USA
| | - Thomas J Ross
- Neuroimaging Research Branch, National Institute on Drug Abuse, Intramural Research Program, 251 Bayview Blvd, Suite 200, Baltimore, MD, USA
| | - Elliot A Stein
- Neuroimaging Research Branch, National Institute on Drug Abuse, Intramural Research Program, 251 Bayview Blvd, Suite 200, Baltimore, MD, USA
| | - Yihong Yang
- Neuroimaging Research Branch, National Institute on Drug Abuse, Intramural Research Program, 251 Bayview Blvd, Suite 200, Baltimore, MD, USA
| | - Hanbing Lu
- Neuroimaging Research Branch, National Institute on Drug Abuse, Intramural Research Program, 251 Bayview Blvd, Suite 200, Baltimore, MD, USA.
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12
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Colon-Perez LM, Tran K, Thompson K, Pace MC, Blum K, Goldberger BA, Gold MS, Bruijnzeel AW, Setlow B, Febo M. The Psychoactive Designer Drug and Bath Salt Constituent MDPV Causes Widespread Disruption of Brain Functional Connectivity. Neuropsychopharmacology 2016; 41:2352-65. [PMID: 26997298 PMCID: PMC4946066 DOI: 10.1038/npp.2016.40] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 03/11/2016] [Accepted: 03/16/2016] [Indexed: 01/16/2023]
Abstract
The abuse of 'bath salts' has raised concerns because of their adverse effects, which include delirium, violent behavior, and suicide ideation in severe cases. The bath salt constituent 3,4-methylenedioxypyrovalerone (MDPV) has been closely linked to these and other adverse effects. The abnormal behavioral pattern produced by acute high-dose MDPV intake suggests possible disruptions of neural communication between brain regions. Therefore, we determined if MDPV exerts disruptive effects on brain functional connectivity, particularly in areas of the prefrontal cortex. Male rats were imaged following administration of a single dose of MDPV (0.3, 1.0, or 3.0 mg/kg) or saline. Resting state brain blood oxygenation level-dependent (BOLD) images were acquired at 4.7 T. To determine the role of dopamine transmission in MDPV-induced changes in functional connectivity, a group of rats received the dopamine D1/D2 receptor antagonist cis-flupenthixol (0.5 mg/kg) 30 min before MDPV. MDPV dose-dependently reduced functional connectivity. Detailed analysis of its effects revealed that connectivity between frontal cortical and striatal areas was reduced. This included connectivity between the prelimbic prefrontal cortex and other areas of the frontal cortex and the insular cortex with hypothalamic, ventral, and dorsal striatal areas. Although the reduced connectivity appeared widespread, connectivity between these regions and somatosensory cortex was not as severely affected. Dopamine receptor blockade did not prevent the MDPV-induced decrease in functional connectivity. The results provide a novel signature of MDPV's in vivo mechanism of action. Reduced brain functional connectivity has been reported in patients suffering from psychosis and has been linked to cognitive dysfunction, audiovisual hallucinations, and negative affective states akin to those reported for MDPV-induced intoxication. The present results suggest that disruption of functional connectivity networks involving frontal cortical and striatal regions could contribute to the adverse effects of MDPV.
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Affiliation(s)
- Luis M Colon-Perez
- Department of Psychiatry, McKnight Brain Institute, University of Florida, Gainesville, FL, USA,Center for Addiction Research and Education, University of Florida, Gainesville, FL, USA
| | - Kelvin Tran
- Department of Psychiatry, McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Khalil Thompson
- Department of Psychiatry, McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Michael C Pace
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Kenneth Blum
- Department of Psychiatry, McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Bruce A Goldberger
- Department of Psychiatry, McKnight Brain Institute, University of Florida, Gainesville, FL, USA,Departments of Pathology, Immunology, and Laboratory Medicine, University of Florida, Gainesville, FL, USA,William R Maples Center for Forensic Medicine, University of Florida, Gainesville, FL, USA
| | - Mark S Gold
- Department of Psychiatry, McKnight Brain Institute, University of Florida, Gainesville, FL, USA,Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Adriaan W Bruijnzeel
- Department of Psychiatry, McKnight Brain Institute, University of Florida, Gainesville, FL, USA,Center for Addiction Research and Education, University of Florida, Gainesville, FL, USA,Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Barry Setlow
- Department of Psychiatry, McKnight Brain Institute, University of Florida, Gainesville, FL, USA,Center for Addiction Research and Education, University of Florida, Gainesville, FL, USA,Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Marcelo Febo
- Department of Psychiatry, McKnight Brain Institute, University of Florida, Gainesville, FL, USA,Center for Addiction Research and Education, University of Florida, Gainesville, FL, USA,Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, USA,Department of Psychiatry, University of Florida Brain Institute, PO Box 100256, Gainesville, FL 32610, USA, Tel: +1 352 294 4911, Fax: +1 352 392 8217, E-mail:
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13
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Lu H, Zou Q, Chefer S, Ross TJ, Vaupel DB, Guillem K, Rea WP, Yang Y, Peoples LL, Stein EA. Abstinence from cocaine and sucrose self-administration reveals altered mesocorticolimbic circuit connectivity by resting state MRI. Brain Connect 2015; 4:499-510. [PMID: 24999822 DOI: 10.1089/brain.2014.0264] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Previous preclinical studies have emphasized that drugs of abuse, through actions within and between mesocorticolimbic (MCL) regions, usurp learning and memory processes normally involved in the pursuit of natural rewards. To distinguish MCL circuit pathobiological neuroadaptations that accompany addiction from general learning processes associated with natural reward, we trained two groups of rats to self-administer either cocaine (IV) or sucrose (orally) followed by an identically enforced 30 day abstinence period. These procedures are known to induce behavioral changes and neuroadaptations. A third group of sedentary animals served as a negative control group for general handling effects. We examined low-frequency spontaneous fluctuations in the functional magnetic resonance imaging (fMRI) signal, known as resting-state functional connectivity (rsFC), as a measure of intrinsic neurobiological interactions between brain regions. Decreased rsFC was seen in the cocaine-SA compared with both sucrose-SA and housing control groups between prelimbic (PrL) cortex and entopeduncular nucleus and between nucleus accumbens core (AcbC) and dorsomedial prefrontal cortex (dmPFC). Moreover, individual differences in cocaine SA escalation predicted connectivity strength only in the Acb-dmPFC circuit. These data provide evidence of fronto-striatal plasticity across the addiction trajectory, which are consistent with Acb-PFC hypoactivity seen in abstinent human drug addicts, indicating potential circuit level biomarkers that may inform therapeutic interventions. They further suggest that available data from cross-sectional human studies may reflect the consequence of rather a predispositional predecessor to their dependence.
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Affiliation(s)
- Hanbing Lu
- 1 Neuroimaging Research Branch, National Institute on Drug Abuse, National Institutes of Health , Baltimore, Maryland
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14
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Buchta WC, Riegel AC. Chronic cocaine disrupts mesocortical learning mechanisms. Brain Res 2015; 1628:88-103. [PMID: 25704202 DOI: 10.1016/j.brainres.2015.02.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 01/28/2015] [Accepted: 02/01/2015] [Indexed: 01/06/2023]
Abstract
The addictive power of drugs of abuse such as cocaine comes from their ability to hijack natural reward and plasticity mechanisms mediated by dopamine signaling in the brain. Reward learning involves burst firing of midbrain dopamine neurons in response to rewards and cues predictive of reward. The resulting release of dopamine in terminal regions is thought to act as a teaching signaling to areas such as the prefrontal cortex and striatum. In this review, we posit that a pool of extrasynaptic dopaminergic D1-like receptors activated in response to dopamine neuron burst firing serve to enable synaptic plasticity in the prefrontal cortex in response to rewards and their cues. We propose that disruptions in these mechanisms following chronic cocaine use contribute to addiction pathology, in part due to the unique architecture of the mesocortical pathway. By blocking dopamine reuptake in the cortex, cocaine elevates dopamine signaling at these extrasynaptic receptors, prolonging D1-receptor activation and the subsequent activation of intracellular signaling cascades, and thus inducing long-lasting maladaptive plasticity. These cellular adaptations may account for many of the changes in cortical function observed in drug addicts, including an enduring vulnerability to relapse. Therefore, understanding and targeting these neuroadaptations may provide cognitive benefits and help prevent relapse in human drug addicts.
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Affiliation(s)
- William C Buchta
- Neurobiology of Addiction Research Center (NARC), Medical University of South Carolina, Charleston, SC 29425, USA
| | - Arthur C Riegel
- Neurobiology of Addiction Research Center (NARC), Medical University of South Carolina, Charleston, SC 29425, USA.
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15
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Synapse Density and Dendritic Complexity Are Reduced in the Prefrontal Cortex following Seven Days of Forced Abstinence from Cocaine Self-Administration. PLoS One 2014; 9:e102524. [PMID: 25072653 PMCID: PMC4114454 DOI: 10.1371/journal.pone.0102524] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 06/19/2014] [Indexed: 12/03/2022] Open
Abstract
Chronic cocaine exposure in both human addicts and in rodent models of addiction reduces prefrontal cortical activity, which subsequently dysregulates reward processing and higher order executive function. The net effect of this impaired gating of behavior is enhanced vulnerability to relapse. Previously we have shown that cocaine-induced increases in brain-derived neurotrophic factor (BDNF) expression in the medial prefrontal cortex (PFC) is a neuroadaptive mechanism that blunts the reinforcing efficacy of cocaine. As BDNF is known to affect neuronal survival and synaptic plasticity, we tested the hypothesis that abstinence from cocaine self-administration would lead to alterations in neuronal morphology and synaptic density in the PFC. Using a novel technique, array tomography and Golgi staining, morphological changes in the rat PFC were analyzed following 14 days of cocaine self-administration and 7 days of forced abstinence. Our results indicate that overall dendritic branching and total synaptic density are significantly reduced in the rat PFC. In contrast, the density of thin dendritic spines are significantly increased on layer V pyramidal neurons of the PFC. These findings indicate that dynamic structural changes occur during cocaine abstinence that may contribute to the observed hypo-activity of the PFC in cocaine-addicted individuals.
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16
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Lai HY, Albaugh DL, Kao YCJ, Younce JR, Shih YYI. Robust deep brain stimulation functional MRI procedures in rats and mice using an MR-compatible tungsten microwire electrode. Magn Reson Med 2014; 73:1246-51. [DOI: 10.1002/mrm.25239] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 02/14/2014] [Accepted: 03/11/2014] [Indexed: 11/08/2022]
Affiliation(s)
- Hsin-Yi Lai
- Department of Neurology; University of North Carolina; Chapel Hill North Carolina USA
- Biomedical Research Imaging Center; University of North Carolina; Chapel Hill North Carolina USA
| | - Daniel L. Albaugh
- Department of Neurology; University of North Carolina; Chapel Hill North Carolina USA
- Biomedical Research Imaging Center; University of North Carolina; Chapel Hill North Carolina USA
- Curriculum in Neurobiology; University of North Carolina; Chapel Hill North Carolina USA
| | - Yu-Chieh Jill Kao
- Department of Neurology; University of North Carolina; Chapel Hill North Carolina USA
- Biomedical Research Imaging Center; University of North Carolina; Chapel Hill North Carolina USA
| | - John R. Younce
- Department of Neurology; University of North Carolina; Chapel Hill North Carolina USA
- Biomedical Research Imaging Center; University of North Carolina; Chapel Hill North Carolina USA
- School of Medicine; University of North Carolina; Chapel Hill North Carolina USA
| | - Yen-Yu Ian Shih
- Department of Neurology; University of North Carolina; Chapel Hill North Carolina USA
- Biomedical Research Imaging Center; University of North Carolina; Chapel Hill North Carolina USA
- Curriculum in Neurobiology; University of North Carolina; Chapel Hill North Carolina USA
- Department of Biomedical Engineering; University of North Carolina; Chapel Hill North Carolina USA
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17
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Lemos IL, Diniz PRB, Peres JFP, Sougey EB. Neuroimagem na dependência de jogos eletrônicos: uma revisão sistemática. JORNAL BRASILEIRO DE PSIQUIATRIA 2014. [DOI: 10.1590/0047-2085000000008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Objetivo: Realizar revisão sistemática de manuscritos que utilizaram a neuroimagem no estudo da dependência de jogos eletrônicos, a fim de identificar as principais regiões cerebrais alteradas. Métodos: Foram realizadas buscas nos seguintes bancos de dados: ScieELO, BVS, Lilacs, Science Direct On Line e PubMed. Não houve data mínima para a pesquisa, sendo considerados os artigos encontrados até julho de 2013. Os descritores utilizados para a presente revisão sistemática da literatura foram: “PET”, “SPECT”, “MRI”, “DTI”, “EEG”, “imaging”, “neuroimaging”, “spectroscopy”, “functional magnetic ressonance”, “structural magnetic ressonance”, “tractography”, “voxel” e “brain”, individualmente cruzados com os descritores “gaming” e “video game addiction”. Resultados: Dos 52 artigos encontrados, 16 foram selecionados: nove usaram fMRI, quatro usaram sRMI, um usou PET e dois usaram EEG. Em relação às alterações funcionais e estruturais, elas foram mais observadas no lobo frontal (córtex pré-frontal dorsolateral, córtex orbitofrontal, giro pré-frontal, giro frontal médio), parietal, temporal (giro para-hipocampal), núcleos da base, tálamo, ínsula e cerebelo. Conclusão: A despeito dos métodos utilizados, os estudos apontaram convergências quanto às reciprocidades cerebrais. Essas alterações neurais são semelhantes às observadas em pacientes dependentes de substâncias e de internet, especialmente durante o estado de fissura. Apesar de apenas recentemente pesquisas de neuroimagem em dependentes de jogos eletrônicos terem sido realizadas, contamos no momento com achados significativos alinhados à compreensão dos mecanismos neurais associados à dependência de jogos eletrônicos e respectiva inserção como categoria nosológica no âmbito psiquiátrico.
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18
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Anastasio NC, Liu S, Maili L, Swinford SE, Lane SD, Fox RG, Hamon SC, Nielsen DA, Cunningham KA, Moeller FG. Variation within the serotonin (5-HT) 5-HT₂C receptor system aligns with vulnerability to cocaine cue reactivity. Transl Psychiatry 2014; 4:e369. [PMID: 24618688 PMCID: PMC3966037 DOI: 10.1038/tp.2013.131] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 10/10/2013] [Accepted: 11/10/2013] [Indexed: 12/15/2022] Open
Abstract
Cocaine dependence remains a challenging public health problem with relapse cited as a major determinant in its chronicity and severity. Environmental contexts and stimuli become reliably associated with its use leading to durable conditioned responses ('cue reactivity') that can predict relapse as well as treatment success. Individual variation in the magnitude and influence of cue reactivity over behavior in humans and animals suggest that cue-reactive individuals may be at greater risk for the progression to addiction and/or relapse. In the present translational study, we investigated the contribution of variation in the serotonin (5-HT) 5-HT2C receptor (5-HT2CR) system in individual differences in cocaine cue reactivity in humans and rodents. We found that cocaine-dependent subjects carrying a single nucleotide polymorphism (SNP) in the HTR2C gene that encodes for the conversion of cysteine to serine at codon 23 (Ser23 variant) exhibited significantly higher attentional bias to cocaine cues in the cocaine-word Stroop task than those carrying the Cys23 variant. In a model of individual differences in cocaine cue reactivity in rats, we identified that high cocaine cue reactivity measured as appetitive approach behavior (lever presses reinforced by the discrete cue complex) correlated with lower 5-HT2CR protein expression in the medial prefrontal cortex and blunted sensitivity to the suppressive effects of the selective 5-HT2CR agonist WAY163909. Our translational findings suggest that the functional status of the 5-HT2CR system is a mechanistic factor in the generation of vulnerability to cocaine-associated cues, an observation that opens new avenues for future development of biomarker and therapeutic approaches to suppress relapse in cocaine dependence.
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Affiliation(s)
- N C Anastasio
- Center for Addiction Research and Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, USA
| | - S Liu
- Center for Neurobehavioral Research on Addictions, Department of Psychiatry and Behavioral Sciences, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - L Maili
- Center for Neurobehavioral Research on Addictions, Department of Psychiatry and Behavioral Sciences, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - S E Swinford
- Center for Addiction Research and Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, USA
| | - S D Lane
- Center for Neurobehavioral Research on Addictions, Department of Psychiatry and Behavioral Sciences, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - R G Fox
- Center for Addiction Research and Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, USA
| | - S C Hamon
- Statistical & Genetic Consulting, LLC, New York, NY, USA
| | - D A Nielsen
- Michael E DeBakey VA Medical Center, Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, TX, USA
| | - K A Cunningham
- Center for Addiction Research and Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, USA,UTMB Center for Addiction Research, University of Texas Medical Branch, Galveston, TX 77555-0615, USA. E-mail:
| | - F G Moeller
- Department of Psychiatry, Virginia Commonwealth University School of Medicine, Richmond, VA, USA
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Kohut SJ, Fivel PA, Mello NK. Differential effects of acute and chronic treatment with the α2-adrenergic agonist, lofexidine, on cocaine self-administration in rhesus monkeys. Drug Alcohol Depend 2013; 133:593-9. [PMID: 23998378 PMCID: PMC3818349 DOI: 10.1016/j.drugalcdep.2013.07.032] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 07/25/2013] [Accepted: 07/30/2013] [Indexed: 10/26/2022]
Abstract
BACKGROUND Lofexidine, an α2-adrenergic agonist, is being investigated as a treatment for reducing opioid withdrawal symptoms and blocking stress-induced relapse to cocaine taking. Opioid abusers are often polydrug abusers and cocaine is one frequent drug of choice. However, relatively little is known about lofexidine interactions with cocaine. The present study investigated the effects of acute and chronic treatment with lofexidine in a pre-clinical model of cocaine self-administration. METHODS Male rhesus monkeys were trained to respond for food (1g) and cocaine (0.01 mg/kg/injection) under a fixed ratio 30 (FR30) or a second order FR2 (VR16:S) schedule of reinforcement. Systematic observations of behavior were conducted during and after chronic treatment with lofexidine. RESULTS Acute treatment with lofexidine (0.1 or 0.32 mg/kg, IM) significantly reduced cocaine self-administration but responding for food was less effected. In contrast, chronic treatment (7-10 days) with lofexidine (0.1-0.32 mg/kg/h, IV) produced a leftward shift in the cocaine self-administration dose-effect curve, but had no effect on food-maintained responding. Lofexidine did not produce any observable side effects during or after treatment. CONCLUSIONS Lofexidine potentiated cocaine's reinforcing effects during chronic treatment. These data suggest that it is unlikely to be effective as a cocaine abuse medication and could enhance risk for cocaine abuse in polydrug abusers.
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Affiliation(s)
- Stephen J. Kohut
- To whom correspondence should be addressed: Stephen J. Kohut, Alcohol and Drug Abuse Research Center, McLean Hospital/Harvard Medical School, 115 Mill Street, Belmont, MA 02478, Phone: 617-855-2167, Fax: 617-855-2195,
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20
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Johnson TR, Smerkers B, Moulder JK, Stellar JR, Febo M. Neural processing of a cocaine-associated odor cue revealed by functional MRI in awake rats. Neurosci Lett 2012; 534:160-5. [PMID: 23262077 DOI: 10.1016/j.neulet.2012.11.054] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Revised: 11/08/2012] [Accepted: 11/19/2012] [Indexed: 02/08/2023]
Abstract
Using an olfactory conditioning procedure, brain stimulation reward threshold measurements, and functional magnetic resonance imaging (fMRI), we investigated brain stimulation reward threshold change and fMRI neural activation in response to a cocaine-associated odor cue. In the first brain stimulation experiment, over 10 days of rate-frequency curve-shift testing, rats were administered intravenous cocaine (1.0mg/kg) paired with a contextual cue of peppermint odor previously placed in the operant chamber or they were given vehicle treatment (no cocaine) in the presence of no olfactory cue. Following a 14-day drug-free rest period, rats were again given the rate-frequency curve-shift threshold test with or without the odor cue. In a second experiment, rats were similarly conditioned with a peppermint odor but with intraperitoneally delivered cocaine (10mg/kg). After a 14 day rest period, rats were imaged on a 7-T MRI for their blood oxygen level dependent (BOLD) in response to the cocaine-paired peppermint odor versus an unpaired neutral lemon odor. In the brain stimulation experiment, expected significant reward threshold shifts were produced by cocaine and, importantly, about half that level of shift was produced by the paired contextual olfactory cue. In the fMRI experiment, the insular cortex showed a significantly greater BOLD activation in cocaine-treated versus saline-treated animals to the olfactory cue, but not with the unpaired lemon scent. These data are in agreement with previous studies suggesting a role of the insular cortex in attributing reward value (positive or negative) to conditioned odor stimuli.
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Affiliation(s)
- Tehya R Johnson
- Behavioral Neuroscience Program, Northeastern University, Boston, MA 02115, USA
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