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Arias-Carrión O, Caraza-Santiago X, Salgado-Licona S, Salama M, Machado S, Nardi AE, Menéndez-González M, Murillo-Rodríguez E. Orquestic regulation of neurotransmitters on reward-seeking behavior. Int Arch Med 2014; 7:29. [PMID: 25061480 PMCID: PMC4108978 DOI: 10.1186/1755-7682-7-29] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 05/31/2014] [Indexed: 01/15/2023] Open
Abstract
The ventral tegmental area is strongly associated with the reward system. Dopamine is released in areas such as the nucleus accumbens and prefrontal cortex as a result of rewarding experiences such as food, sex, and neutral stimuli that become associated with them. Electrical stimulation of the ventral tegmental area or its output pathways can itself serve as a potent reward. Different drugs that increase dopamine levels are intrinsically rewarding. Although the dopaminergic system represent the cornerstone of the reward system, other neurotransmitters such as endogenous opioids, glutamate, γ-Aminobutyric acid, acetylcholine, serotonin, adenosine, endocannabinoids, orexins, galanin and histamine all affect this mesolimbic dopaminergic system. Consequently, genetic variations of neurotransmission are thought influence reward processing that in turn may affect distinctive social behavior and susceptibility to addiction. Here, we discuss current evidence on the orquestic regulation of different neurotranmitters on reward-seeking behavior and its potential effect on drug addiction.
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Affiliation(s)
- Oscar Arias-Carrión
- Unidad de Trastornos del Movimiento y Sueño (TMS), Hospital General Dr. Manuel Gea González, Mexico City, Mexico ; Unidad de Trastornos del Movimiento y Sueño (TMS), Hospital General Ajusco Medio, Mexico City, Mexico
| | - Xanic Caraza-Santiago
- Unidad de Trastornos del Movimiento y Sueño (TMS), Hospital General Dr. Manuel Gea González, Mexico City, Mexico
| | - Sergio Salgado-Licona
- Unidad de Trastornos del Movimiento y Sueño (TMS), Hospital General Dr. Manuel Gea González, Mexico City, Mexico
| | - Mohamed Salama
- Toxicology Department and Medical Experimental Research Center (MERC), Faculty of Medicine, Mansoura University, Mansoura, Egypt
| | - Sergio Machado
- Panic and Respiration, Institute of Psychiatry of Federal University of Rio de Janeiro, Rio de Janeiro, Brazil ; Physical Activity Neuroscience Physical Activity Sciences Postgraduate Program, Salgado de Oliveira University, Niterói, Brazil
| | - Antonio Egidio Nardi
- Panic and Respiration, Institute of Psychiatry of Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | | | - Eric Murillo-Rodríguez
- Laboratorio de Neurociencias Moleculares e Integrativas, Escuela de Medicina, División Ciencias de la Salud, Universidad Anáhuac Mayab, Mérida, Yucatán, Mexico
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202
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The action of orexin B on passive avoidance learning. Involvement of neurotransmitters. Behav Brain Res 2014; 272:1-7. [PMID: 24931796 DOI: 10.1016/j.bbr.2014.06.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 06/05/2014] [Accepted: 06/08/2014] [Indexed: 11/22/2022]
Abstract
The extensive projection of orexigenic neurons and the diffuse expression of orexin receptors suggest that endogenous orexins are involved in several physiological functions of the central nervous system, including learning and memory. Our previous study demonstrated that orexin A improves learning, consolidation and retrieval processes, which involves α- and β-adrenergic, cholinergic, dopaminergic, GABA-A-ergic, opiate and nitrergic neurotransmissions. However, we have little evidence about the action of orexin B on memory processes and the underlying neuromodulation. Therefore, the aim of the present study was to investigate the action of orexin B on passive avoidance learning and the involvement of neurotransmitters in this action in rats. Accordingly, rats were pretreated with the selective orexin 2 receptor (OX2R) antagonist, EMPA; the γ-aminobutyric acid subunit A (GABA-A) receptor antagonist, the bicuculline; a D2, D3, D4 dopamine receptor antagonist, haloperidol; the nonselective opioid receptor antagonist, naloxone; the non-specific nitric oxide synthase (NOS) inhibitor, nitro-l-arginine; the nonselective α-adrenergic receptor antagonist, phenoxybenzamine and the β-adrenergic receptor antagonist, propranolol. Our results demonstrate that orexin B can improve learning, consolidation of memory and retrieval. EMPA reversed completely the action of orexin B on memory consolidation. Bicuculline blocked fully; naloxone, nitro-l-arginine, phenoxybenzamine and propranolol attenuated the orexin B-induced memory consolidation, whereas haloperidol was ineffective. These data suggest that orexin B improves memory functions through OX2R and GABA-ergic, opiate, nitrergic, α- and β-adrenergic neurotransmissions are also involved in this action.
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203
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Zarepour L, Fatahi Z, Sarihi A, Haghparast A. Blockade of orexin-1 receptors in the ventral tegmental area could attenuate the lateral hypothalamic stimulation-induced potentiation of rewarding properties of morphine. Neuropeptides 2014; 48:179-85. [PMID: 24793540 DOI: 10.1016/j.npep.2014.04.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Revised: 04/09/2014] [Accepted: 04/11/2014] [Indexed: 10/25/2022]
Abstract
The orexins (hypocretins) are lateral hypothalamic (LH) neuropeptides that have been implicated in a variety of behaviors ranging from feeding to sleep and arousal. Evidence from animal models suggests a role for orexins in reward processing and drug addiction. In the present study, we investigated the direct effect of an orexin antagonist in the ventral tegmental area (VTA) on acquisition and expression of morphine conditioned place preference (CPP) induced by concurrent stimulation of the LH. Eighty-one adult male Wistar rats weighing 220-280 g were unilaterally implanted by two separate cannulae into the LH and VTA. The CPP paradigm was done; conditioning score and locomotor activity were recorded by Ethovision software. The animals received SB334867 as a selective orexin-1 receptor antagonist (0.1, 1 and 10 nmol/0.3 μl DMSO) in the VTA, just 5 min prior to intra-LH administration of ineffective dose of carbachol as a cholinergic agonist (62.5 nmol/0.5 μl saline) that stimulates orexin neurons in the LH and ineffective dose of morphine (1 mg/kg, subcutaneously) concurrently during conditioning phase (acquisition experiments) or post-conditioning phase (expression experiments). Data showed that the blockade of orexin-1 receptors in the VTA could inhibit the acquisition (development) but not expression of LH stimulation-induced morphine CPP in the rats. Our findings suggest that the orexinergic projections from the LH to the VTA are involved in the development of the LH stimulation-induced potentiation of morphine rewarding properties and orexin-1 receptors in the VTA have a substantial role in this phenomenon.
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Affiliation(s)
- Leila Zarepour
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, P.O. Box 19615-1178, Tehran, Iran
| | - Zahra Fatahi
- Physiology-Pharmacology Research Center, Rafsanjan University of Medical Sciences, Rafsanjan, Iran
| | - Abdolrahman Sarihi
- Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran.
| | - Abbas Haghparast
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, P.O. Box 19615-1178, Tehran, Iran.
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204
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Quarta D, Smolders I. Rewarding, reinforcing and incentive salient events involve orexigenic hypothalamic neuropeptides regulating mesolimbic dopaminergic neurotransmission. Eur J Pharm Sci 2014; 57:2-10. [DOI: 10.1016/j.ejps.2014.01.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 01/19/2014] [Indexed: 12/22/2022]
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205
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Marchant NJ, Rabei R, Kaganovsky K, Caprioli D, Bossert JM, Bonci A, Shaham Y. A critical role of lateral hypothalamus in context-induced relapse to alcohol seeking after punishment-imposed abstinence. J Neurosci 2014; 34:7447-57. [PMID: 24872550 PMCID: PMC4035512 DOI: 10.1523/jneurosci.0256-14.2014] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
In human alcoholics, abstinence is often self-imposed, despite alcohol availability, because of the negative consequences of excessive use. During abstinence, relapse is often triggered by exposure to contexts associated with alcohol use. We recently developed a rat model that captures some features of this human condition: exposure to the alcohol self-administration environment (context A), after punishment-imposed suppression of alcohol self-administration in a different environment (context B), provoked renewal of alcohol seeking in alcohol-preferring P rats. The mechanisms underlying context-induced renewal of alcohol seeking after punishment-imposed abstinence are unknown. Here, we studied the role of the lateral hypothalamus (LH) and its forebrain projections in this effect. We first determined the effect of context-induced renewal of alcohol seeking on Fos (a neuronal activity marker) expression in LH. We next determined the effect of LH reversible inactivation by GABAA + GABAB receptor agonists (muscimol + baclofen) on this effect. Finally, we determined neuronal activation in brain areas projecting to LH during context-induced renewal tests by measuring double labeling of the retrograde tracer cholera toxin subunit B (CTb; injected in LH) with Fos. Context-induced renewal of alcohol seeking after punishment-imposed abstinence was associated with increased Fos expression in LH. Additionally, renewal was blocked by muscimol + baclofen injections into LH. Finally, double-labeling analysis of CTb + Fos showed that context-induced renewal of alcohol seeking after punishment-imposed abstinence was associated with selective activation of accumbens shell neurons projecting to LH. The results demonstrate an important role of LH in renewal of alcohol seeking after punishment-imposed abstinence and suggest a role of accumbens shell projections to LH in this form of relapse.
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Affiliation(s)
- Nathan J Marchant
- Behavioral Neuroscience Research Branch and Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria 3052, Australia,
| | - Rana Rabei
- Behavioral Neuroscience Research Branch and
| | | | | | | | - Antonello Bonci
- Cellular Neurobiology Research Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, Baltimore, Maryland 21224, Solomon H. Snyder Department of Neuroscience and Department of Psychiatry, Johns Hopkins University, Baltimore, Maryland 21287
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206
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Navailles S, Guillem K, Vouillac-Mendoza C, Ahmed SH. Coordinated Recruitment of Cortical–Subcortical Circuits and Ascending Dopamine and Serotonin Neurons During Inhibitory Control of Cocaine Seeking in Rats. Cereb Cortex 2014; 25:3167-81. [DOI: 10.1093/cercor/bhu112] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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207
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Castro DC, Berridge KC. Advances in the neurobiological bases for food 'liking' versus 'wanting'. Physiol Behav 2014; 136:22-30. [PMID: 24874776 DOI: 10.1016/j.physbeh.2014.05.022] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2013] [Revised: 04/29/2014] [Accepted: 05/19/2014] [Indexed: 02/04/2023]
Abstract
The neural basis of food sensory pleasure has become an increasingly studied topic in neuroscience and psychology. Progress has been aided by the discovery of localized brain subregions called hedonic hotspots in the early 2000s, which are able to causally amplify positive affective reactions to palatable tastes ('liking') in response to particular neurochemical or neurobiological stimulations. Those hedonic mechanisms are at least partly distinct from larger mesocorticolimbic circuitry that generates the incentive motivation to eat ('wanting'). In this review, we aim to describe findings on these brain hedonic hotspots, especially in the nucleus accumbens and ventral pallidum, and discuss their role in generating food pleasure and appetite.
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Affiliation(s)
- D C Castro
- Department of Psychology, University of Michigan, Ann Arbor, MI 48109, USA.
| | - K C Berridge
- Department of Psychology, University of Michigan, Ann Arbor, MI 48109, USA
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208
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Deats SP, Adidharma W, Lonstein JS, Yan L. Attenuated orexinergic signaling underlies depression-like responses induced by daytime light deficiency. Neuroscience 2014; 272:252-60. [PMID: 24813431 DOI: 10.1016/j.neuroscience.2014.04.069] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 04/24/2014] [Accepted: 04/28/2014] [Indexed: 01/01/2023]
Abstract
Light has profound effects on mood, as exemplified by seasonal affective disorder (SAD) and the beneficial effects of bright light therapy. However, the underlying neural pathways through which light regulates mood are not well understood. Our previous work has developed the diurnal grass rat, Arvicanthis niloticus, as an animal model of SAD (Leach et al., 2013a,b). By utilizing a 12:12-h dim light:dark (DLD) paradigm that simulates the lower light intensity of winter, we showed that the animals housed in DLD exhibited increased depression-like behaviors in the forced swim test (FST) and sweet solution preference (SSP) compared to animals housed in bright light during the day (BLD). The objective of the present study was to test the hypothesis that light affects mood by acting on the brain orexinergic system in the diurnal grass rat model of SAD. First, orexin A immunoreactivity (OXA-ir) was examined in DLD and BLD grass rats. Results revealed a reduction in the number of OXA-ir neurons in the hypothalamus and attenuated OXA-ir fiber density in the dorsal raphe nucleus of animals in the DLD compared to those in the BLD group. Then, the animals in BLD were treated systemically with SB-334867, a selective orexin 1 receptor (OX1R) antagonist, which led to a depressive phenotype characterized by increased immobility in the FST and a decrease in SSP compared to vehicle-treated controls. Results suggest that attenuated orexinergic signaling is associated with increased depression-like behaviors in grass rats, and support the hypothesis that the orexinergic system mediates the effects of light on mood.
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Affiliation(s)
- S P Deats
- Department of Psychology, Michigan State University, East Lansing, MI 48824, USA
| | - W Adidharma
- Department of Psychology, Michigan State University, East Lansing, MI 48824, USA
| | - J S Lonstein
- Department of Psychology, Michigan State University, East Lansing, MI 48824, USA; Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA
| | - L Yan
- Department of Psychology, Michigan State University, East Lansing, MI 48824, USA; Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA.
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209
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Rorabaugh JM, Stratford JM, Zahniser NR. A relationship between reduced nucleus accumbens shell and enhanced lateral hypothalamic orexin neuronal activation in long-term fructose bingeing behavior. PLoS One 2014; 9:e95019. [PMID: 24736531 PMCID: PMC3988143 DOI: 10.1371/journal.pone.0095019] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Accepted: 03/21/2014] [Indexed: 02/06/2023] Open
Abstract
Fructose accounts for 10% of daily calories in the American diet. Fructose, but not glucose, given intracerebroventricularly stimulates homeostatic feeding mechanisms within the hypothalamus; however, little is known about how fructose affects hedonic feeding centers. Repeated ingestion of sucrose, a disaccharide of fructose and glucose, increases neuronal activity in hedonic centers, the nucleus accumbens (NAc) shell and core, but not the hypothalamus. Rats given glucose in the intermittent access model (IAM) display signatures of hedonic feeding including bingeing and altered DA receptor (R) numbers within the NAc. Here we examined whether substituting fructose for glucose in this IAM produces bingeing behavior, alters DA Rs and activates hedonic and homeostatic feeding centers. Following long-term (21-day) exposure to the IAM, rats given 8–12% fructose solutions displayed fructose bingeing but unaltered DA D1R or D2R number. Fructose bingeing rats, as compared to chow bingeing controls, exhibited reduced NAc shell neuron activation, as determined by c-Fos-immunoreactivity (Fos-IR). This activation was negatively correlated with orexin (Orx) neuron activation in the lateral hypothalamus/perifornical area (LH/PeF), a brain region linking homeostatic to hedonic feeding centers. Following short-term (2-day) access to the IAM, rats exhibited bingeing but unchanged Fos-IR, suggesting only long-term fructose bingeing increases Orx release. In long-term fructose bingeing rats, pretreatment with the Ox1R antagonist SB-334867 (30 mg/kg; i.p.) equally reduced fructose bingeing and chow intake, resulting in a 50% reduction in calories. Similarly, in control rats, SB-334867 reduced chow/caloric intake by 60%. Thus, in the IAM, Ox1Rs appear to regulate feeding based on caloric content rather than palatability. Overall, our results, in combination with the literature, suggest individual monosaccharides activate distinct neuronal circuits to promote feeding behavior. Specifically, long-term fructose bingeing activates a hyperphagic circuit composed in part of NAc shell and LH/PeF Orx neurons.
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Affiliation(s)
- Jacki M. Rorabaugh
- Department of Pharmacology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
- * E-mail:
| | - Jennifer M. Stratford
- Rocky Mountain Taste and Smell Center, Department of Cell and Developmental Biology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Nancy R. Zahniser
- Department of Pharmacology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
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210
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Cruz HG, Hoever P, Chakraborty B, Schoedel K, Sellers EM, Dingemanse J. Assessment of the abuse liability of a dual orexin receptor antagonist: a crossover study of almorexant and zolpidem in recreational drug users. CNS Drugs 2014; 28:361-72. [PMID: 24627301 DOI: 10.1007/s40263-014-0150-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
BACKGROUND Dual orexin receptor antagonists (DORAs) enable initiation and maintenance of sleep in patients with primary insomnia. Blockade of the orexin system has shown reduction of drug-seeking behavior in animal studies, supporting the role of orexin antagonism as a novel approach for treating substance abuse. Since hypnotics are traditionally associated with misuse, a lack of abuse liability of DORAs would offer significant benefits over current therapies for sleep disorders. METHODS In this randomized, crossover, proof-of-concept study, single oral doses of the DORA almorexant (200, 400, and 1,000 mg) were administered to healthy subjects with previous non-therapeutic experience with central nervous system depressants and were compared with placebo and single oral doses of zolpidem (20 and 40 mg), a benzodiazepine-like drug. Subjective measures of abuse potential (visual analog scales [VAS], Addiction Research Center Inventory, and Subjective Drug Value) and objective measures (divided attention [DA]) were evaluated over 24 h post-dose in 33 evaluable subjects. RESULTS Drug Liking VAS peak effect (E max; primary endpoint) was significantly higher for all doses of almorexant and zolpidem compared with placebo (p<0.001). Almorexant 200 mg showed significantly less 'Drug Liking' than both zolpidem doses (p<0.01), and almorexant 400 mg had smaller effects than zolpidem 20 mg (p<0.05), while almorexant 1,000 mg was not different from either zolpidem dose. Results were similar for other subjective measures, although almorexant generally showed smaller negative and perceptual effects compared with zolpidem. Almorexant also showed less cognitive impairment compared with zolpidem on most DA endpoints. CONCLUSION This study in humans investigating single doses of almorexant is the first to explore and show abuse liability of a DORA, a class of compounds that is not only promising for the treatment of sleep disorders, but also of addiction.
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Affiliation(s)
- Hans G Cruz
- Actelion Pharmaceuticals Ltd, Clinical Pharmacology, Gewerbestrasse 16, 4123, Allschwil, Switzerland
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211
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Flores Á, Maldonado R, Berrendero F. The hypocretin/orexin receptor-1 as a novel target to modulate cannabinoid reward. Biol Psychiatry 2014; 75:499-507. [PMID: 23896204 DOI: 10.1016/j.biopsych.2013.06.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 05/22/2013] [Accepted: 06/19/2013] [Indexed: 12/29/2022]
Abstract
BACKGROUND Cannabis is the most widely used illicit drug in the world. Although there is a high prevalence of users who seek treatment for cannabis dependence, no accepted pharmacologic treatment is available to facilitate and maintain abstinence. The hypocretin/orexin system plays a critical role in drug addiction, but the potential participation of this system in the addictive properties of cannabinoids is unknown. METHODS We investigated the effects of hypocretins in the intravenous self-administration of the synthetic cannabinoid agonist WIN55,212-2 using hypocretin receptor-1 (Hcrtr-1) and hypocretin receptor-2 antagonists and Hcrtr-1 knockout mice. Additional groups of mice were trained to obtain water to rule out operant responding impairments. Activation of hypocretin neurons was analyzed by using double-label immunofluorescence of FosB/ΔFosB with hypocretin-1. Microdialysis studies were performed to evaluate dopamine extracellular levels in the nucleus accumbens after acute Δ(9)-tetrahydrocannabinol administration. RESULTS Systemic administration of the Hcrtr-1 antagonist SB334867 reduced intravenous self-administration of WIN55,212-2, as well as the maximum effort to obtain a WIN55,212-2 infusion, as revealed under a progressive ratio schedule. This role of Hcrtr-1 in the reinforcing and motivational properties of WIN55,212-2 was confirmed in Hcrtr-1 knockout mice. Contingent, but not noncontingent, WIN55,212-2 self-administration increased the percentage of hypocretin cells expressing FosB/ΔFosB in the lateral hypothalamus. The enhancement in dopamine extracellular levels in the nucleus accumbens induced by Δ(9)-tetrahydrocannabinol was blocked in mice lacking the Hcrtr-1. CONCLUSIONS These findings demonstrate that Hcrtr-1 modulates the reinforcing properties of cannabinoids, which could have a clear therapeutic interest.
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Affiliation(s)
- África Flores
- Laboratory of Neuropharmacology, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona, Spain
| | - Rafael Maldonado
- Laboratory of Neuropharmacology, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona, Spain
| | - Fernando Berrendero
- Laboratory of Neuropharmacology, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona, Spain.
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212
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Erbs E, Faget L, Scherrer G, Matifas A, Filliol D, Vonesch JL, Koch M, Kessler P, Hentsch D, Birling MC, Koutsourakis M, Vasseur L, Veinante P, Kieffer BL, Massotte D. A mu-delta opioid receptor brain atlas reveals neuronal co-occurrence in subcortical networks. Brain Struct Funct 2014; 220:677-702. [PMID: 24623156 PMCID: PMC4341027 DOI: 10.1007/s00429-014-0717-9] [Citation(s) in RCA: 205] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2013] [Accepted: 01/27/2014] [Indexed: 12/19/2022]
Abstract
Opioid receptors are G protein-coupled receptors (GPCRs) that modulate brain function at all levels of neural integration, including autonomic, sensory, emotional and cognitive processing. Mu (MOR) and delta (DOR) opioid receptors functionally interact in vivo, but whether interactions occur at circuitry, cellular or molecular levels remains unsolved. To challenge the hypothesis of MOR/DOR heteromerization in the brain, we generated redMOR/greenDOR double knock-in mice and report dual receptor mapping throughout the nervous system. Data are organized as an interactive database offering an opioid receptor atlas with concomitant MOR/DOR visualization at subcellular resolution, accessible online. We also provide co-immunoprecipitation-based evidence for receptor heteromerization in these mice. In the forebrain, MOR and DOR are mainly detected in separate neurons, suggesting system-level interactions in high-order processing. In contrast, neuronal co-localization is detected in subcortical networks essential for survival involved in eating and sexual behaviors or perception and response to aversive stimuli. In addition, potential MOR/DOR intracellular interactions within the nociceptive pathway offer novel therapeutic perspectives.
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Affiliation(s)
- Eric Erbs
- Department of Neurogenetics and Translational Medicine, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, INSERM, Université de Strasbourg, 1 rue Laurent Fries, BP10142, 67404 Illkirch cedex, France
| | - Lauren Faget
- Department of Neurogenetics and Translational Medicine, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, INSERM, Université de Strasbourg, 1 rue Laurent Fries, BP10142, 67404 Illkirch cedex, France
- Present Address: University of California, La Jolla, CA 92093 USA
| | - Gregory Scherrer
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford Institute for Neuro-Innovation and Translational Neurosciences, Stanford University, Stanford, 94305 CA USA
| | - Audrey Matifas
- Department of Neurogenetics and Translational Medicine, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, INSERM, Université de Strasbourg, 1 rue Laurent Fries, BP10142, 67404 Illkirch cedex, France
| | - Dominique Filliol
- Department of Neurogenetics and Translational Medicine, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, INSERM, Université de Strasbourg, 1 rue Laurent Fries, BP10142, 67404 Illkirch cedex, France
| | - Jean-Luc Vonesch
- Imaging Centre, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, INSERM, Université de Strasbourg, BP 10142, 1 rue Laurent Fries, 67404 Illkirch cedex, France
| | - Marc Koch
- Imaging Centre, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, INSERM, Université de Strasbourg, BP 10142, 1 rue Laurent Fries, 67404 Illkirch cedex, France
| | - Pascal Kessler
- Imaging Centre, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, INSERM, Université de Strasbourg, BP 10142, 1 rue Laurent Fries, 67404 Illkirch cedex, France
| | - Didier Hentsch
- Imaging Centre, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, INSERM, Université de Strasbourg, BP 10142, 1 rue Laurent Fries, 67404 Illkirch cedex, France
| | | | - Manoussos Koutsourakis
- Institut Clinique de la Souris, 1 rue Laurent Fries, 67404 Illkirch cedex, France
- Present Address: Sanger Institute, Hinxton, Cambridge CB 10 1SA UK
| | - Laurent Vasseur
- Institut Clinique de la Souris, 1 rue Laurent Fries, 67404 Illkirch cedex, France
| | - Pierre Veinante
- Institut des Neurosciences Cellulaires et Intégratives CNRS UPR 3212, 5 rue Blaise Pascal, 67084 Strasbourg cedex 03, France
| | - Brigitte L. Kieffer
- Department of Neurogenetics and Translational Medicine, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, INSERM, Université de Strasbourg, 1 rue Laurent Fries, BP10142, 67404 Illkirch cedex, France
| | - Dominique Massotte
- Department of Neurogenetics and Translational Medicine, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, INSERM, Université de Strasbourg, 1 rue Laurent Fries, BP10142, 67404 Illkirch cedex, France
- Institut des Neurosciences Cellulaires et Intégratives CNRS UPR 3212, 5 rue Blaise Pascal, 67084 Strasbourg cedex 03, France
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Weymann KB, Wood LJ, Zhu X, Marks DL. A role for orexin in cytotoxic chemotherapy-induced fatigue. Brain Behav Immun 2014; 37:84-94. [PMID: 24216337 PMCID: PMC3951615 DOI: 10.1016/j.bbi.2013.11.003] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 10/16/2013] [Accepted: 11/01/2013] [Indexed: 02/08/2023] Open
Abstract
Fatigue is the most common symptom related to cytotoxic chemotherapeutic treatment of cancer. Peripheral inflammation associated with cytotoxic chemotherapy is likely a causal factor of fatigue. The neural mechanisms by which cytotoxic chemotherapy associated inflammation induces fatigue behavior are not known. This lack of knowledge hinders development of interventions to reduce or prevent this disabling symptom. Infection induced fatigue/lethargy in rodents is mediated by suppression of hypothalamic orexin activity. Orexin is critical for maintaining wakefulness and motivated behavior. Though there are differences between infection and cytotoxic chemotherapy in some symptoms, both induce peripheral inflammation and fatigue. Based on these similarities we hypothesized that cytotoxic chemotherapy induces fatigue by disrupting orexin neuron activity. We found that a single dose of a cytotoxic chemotherapy cocktail (cyclophosphamide, adriamycin, 5-fluorouracil - CAF) induced fatigue/lethargy in mice and rats as evidenced by a significant decline in voluntary locomotor activity measured by telemetry. CAF induced inflammatory gene expression - IL-1R1 (p<0.001), IL-6 (p<0.01), TNFα (p<0.01), and MCP-1 (p<0.05) - in the rodent hypothalamus 6-24h after treatment during maximum fatigue/lethargy. CAF decreased orexin neuron activity as reflected by decreased nuclear cFos localization in orexin neurons 24h after treatment (p<0.05) and by decreased orexin-A in cerebrospinal fluid 16 h after treatment (p<0.001). Most importantly, we found that central administration of 1 μg orexin-A restored activity in CAF-treated rats (p<0.05). These results demonstrate that cytotoxic chemotherapy induces hypothalamic inflammation and that suppression of hypothalamic orexin neuron activity has a causal role in cytotoxic chemotherapy-induced fatigue in rodents.
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Affiliation(s)
- K B Weymann
- Oregon Health & Science University, Portland, OR 97239, United States.
| | - L J Wood
- Oregon Health & Science University, Portland, OR 97239, United States; School of Nursing, MGH Institute of Health Professions, Boston, MA 02129, United States.
| | - X Zhu
- Oregon Health & Science University, Portland, OR 97239, United States.
| | - D L Marks
- Oregon Health & Science University, Portland, OR 97239, United States.
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214
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Staples LG, Cornish JL. The orexin-1 receptor antagonist SB-334867 attenuates anxiety in rats exposed to cat odor but not the elevated plus maze: an investigation of Trial 1 and Trial 2 effects. Horm Behav 2014; 65:294-300. [PMID: 24397997 DOI: 10.1016/j.yhbeh.2013.12.014] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 12/24/2013] [Accepted: 12/26/2013] [Indexed: 01/22/2023]
Abstract
The orexins are hypothalamic neuropeptides most well known for their roles in regulating feeding and sleeping behaviors. Recent findings suggest that orexin-A may also modulate anxiety, although how and when the orexin system is involved remains unclear. To address this, we investigated the dose-dependent effects of the orexin-1 receptor antagonist SB-334867 in two rodent models of anxiety: the cat odor avoidance model and the elevated plus maze. In both models we tested the effects of SB-334867 when anxiety is novel (Trial 1) and familiar (Trial 2). In the first experiment, Wistar rats were treated with vehicle or SB-334867 (5, 10 or 20mg/kg, i.p.) prior to their first or second exposure to cat odor. During Trial 1, rats treated with 10mg/kg of SB-334867 approached the cat odor stimulus more than vehicle-treated rats. During Trial 2 the effects were more marked, with 10mg/kg of SB-334867 increasing approach times, increasing the number of times rats exited the hide box to engage in exploratory behavior, and decreasing overall hide times. In addition, the 20mg/kg dose decreased general activity during Trial 2. In the second experiment, the effects of SB-334867 (10 and 20mg/kg) were tested in the elevated plus maze. There were no significant differences produced by drug treatment during either Trial 1 or Trial 2. Results suggest that SB-334867 decreases anxiety induced by some, but not all, stressors.
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Affiliation(s)
- Lauren G Staples
- Department of Psychology C3A, Macquarie University, NSW 2109, Australia.
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215
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Yeoh JW, Campbell EJ, James MH, Graham BA, Dayas CV. Orexin antagonists for neuropsychiatric disease: progress and potential pitfalls. Front Neurosci 2014; 8:36. [PMID: 24616658 PMCID: PMC3934415 DOI: 10.3389/fnins.2014.00036] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Accepted: 02/10/2014] [Indexed: 11/20/2022] Open
Abstract
The tight regulation of sleep/wake states is critical for mental and physiological wellbeing. For example, dysregulation of sleep/wake systems predisposes individuals to metabolic disorders such as obesity and psychiatric problems, including depression. Contributing to this understanding, the last decade has seen significant advances in our appreciation of the complex interactions between brain systems that control the transition between sleep and wake states. Pivotal to our increased understanding of this pathway was the description of a group of neurons in the lateral hypothalamus (LH) that express the neuropeptides orexin A and B (hypocretin, Hcrt-1 and Hcrt-2). Orexin neurons were quickly placed at center stage with the demonstration that loss of normal orexin function is associated with the development of narcolepsy—a condition in which sufferers fail to maintain normal levels of daytime wakefulness. Since these initial seminal findings, much progress has been made in our understanding of the physiology and function of the orexin system. For example, the orexin system has been identified as a key modulator of autonomic and neuroendocrine function, arousal, reward and attention. Notably, studies in animals suggest that dysregulation of orexin function is associated with neuropsychiatric states such as addiction and mood disorders including depression and anxiety. This review discusses the progress associated with therapeutic attempts to restore orexin system function and treat neuropsychiatric conditions such as addiction, depression and anxiety. We also highlight potential pitfalls and challenges associated with targeting this system to treat these neuropsychiatric states.
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Affiliation(s)
- Jiann Wei Yeoh
- Neurobiology of Addiction Laboratory, The Centre for Translational Neuroscience and Mental Health Research, School of Biomedical Sciences and Pharmacy, University of Newcastle and the Hunter Medical Research Institute Newcastle, NSW, Australia
| | - Erin J Campbell
- Neurobiology of Addiction Laboratory, The Centre for Translational Neuroscience and Mental Health Research, School of Biomedical Sciences and Pharmacy, University of Newcastle and the Hunter Medical Research Institute Newcastle, NSW, Australia
| | - Morgan H James
- Neurobiology of Addiction Laboratory, The Centre for Translational Neuroscience and Mental Health Research, School of Biomedical Sciences and Pharmacy, University of Newcastle and the Hunter Medical Research Institute Newcastle, NSW, Australia
| | - Brett A Graham
- Neurobiology of Addiction Laboratory, The Centre for Translational Neuroscience and Mental Health Research, School of Biomedical Sciences and Pharmacy, University of Newcastle and the Hunter Medical Research Institute Newcastle, NSW, Australia
| | - Christopher V Dayas
- Neurobiology of Addiction Laboratory, The Centre for Translational Neuroscience and Mental Health Research, School of Biomedical Sciences and Pharmacy, University of Newcastle and the Hunter Medical Research Institute Newcastle, NSW, Australia
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216
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Anderson RI, Becker HC, Adams BL, Jesudason CD, Rorick-Kehn LM. Orexin-1 and orexin-2 receptor antagonists reduce ethanol self-administration in high-drinking rodent models. Front Neurosci 2014; 8:33. [PMID: 24616657 PMCID: PMC3933945 DOI: 10.3389/fnins.2014.00033] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 02/08/2014] [Indexed: 11/13/2022] Open
Abstract
To examine the role of orexin-1 and orexin-2 receptor activity on ethanol self-administration, compounds that differentially target orexin (OX) receptor subtypes were assessed in various self-administration paradigms using high-drinking rodent models. Effects of the OX1 antagonist SB334867, the OX2 antagonist LSN2424100, and the mixed OX1/2 antagonist almorexant (ACT-078573) on home cage ethanol consumption were tested in ethanol-preferring (P) rats using a 2-bottle choice procedure. In separate experiments, effects of SB334867, LSN2424100, and almorexant on operant ethanol self-administration were assessed in P rats maintained on a progressive ratio operant schedule of reinforcement. In a third series of experiments, SB334867, LSN2424100, and almorexant were administered to ethanol-preferring C57BL/6J mice to examine effects of OX receptor blockade on ethanol intake in a binge-like drinking (drinking-in-the-dark) model. In P rats with chronic home cage free-choice ethanol access, SB334867 and almorexant significantly reduced ethanol intake, but almorexant also reduced water intake, suggesting non-specific effects on consummatory behavior. In the progressive ratio operant experiments, LSN2424100 and almorexant reduced breakpoints and ethanol consumption in P rats, whereas the almorexant inactive enantiomer and SB334867 did not significantly affect the motivation to consume ethanol. As expected, vehicle-injected mice exhibited binge-like drinking patterns in the drinking-in-the-dark model. All three OX antagonists reduced both ethanol intake and resulting blood ethanol concentrations relative to vehicle-injected controls, but SB334867 and LSN2424100 also reduced sucrose consumption in a different cohort of mice, suggesting non-specific effects. Collectively, these results contribute to a growing body of evidence indicating that OX1 and OX2 receptor activity influences ethanol self-administration, although the effects may not be selective for ethanol consumption.
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Affiliation(s)
- Rachel I Anderson
- Medical University of South Carolina Charleston, SC, USA ; Charleston Alcohol Research Center Charleston, SC, USA
| | - Howard C Becker
- Medical University of South Carolina Charleston, SC, USA ; Charleston Alcohol Research Center Charleston, SC, USA ; Ralph H. Johnson VA Medical Center USA
| | - Benjamin L Adams
- Lilly Research Laboratories, Eli Lilly and Company Indianapolis, IN, USA
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217
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Obesity--a neuropsychological disease? Systematic review and neuropsychological model. Prog Neurobiol 2014; 114:84-101. [PMID: 24394671 DOI: 10.1016/j.pneurobio.2013.12.001] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 11/26/2013] [Accepted: 12/08/2013] [Indexed: 01/01/2023]
Abstract
Obesity is a global epidemic associated with a series of secondary complications and comorbid diseases such as diabetes mellitus, cardiovascular disease, sleep-breathing disorders, and certain forms of cancer. On the surface, it seems that obesity is simply the phenotypic manifestation of deliberately flawed food intake behavior with the consequence of dysbalanced energy uptake and expenditure and can easily be reversed by caloric restriction and exercise. Notwithstanding this assumption, the disappointing outcomes of long-term clinical studies based on this assumption show that the problem is much more complex. Obviously, recent studies render that specific neurocircuits involved in appetite regulation are etiologically integrated in the pathomechanism, suggesting obesity should be regarded as a neurobiological disease rather than the consequence of detrimental food intake habits. Moreover, apart from the physical manifestation of overeating, a growing body of evidence suggests a close relationship with psychological components comprising mood disturbances, altered reward perception and motivation, or addictive behavior. Given that current dietary and pharmacological strategies to overcome the burgeoning threat of the obesity problem are of limited efficacy, bear the risk of adverse side-effects, and in most cases are not curative, new concepts integratively focusing on the fundamental neurobiological and psychological mechanisms underlying overeating are urgently required. This new approach to develop preventive and therapeutic strategies would justify assigning obesity to the spectrum of neuropsychological diseases. Our objective is to give an overview on the current literature that argues for this view and, on the basis of this knowledge, to deduce an integrative model for the development of obesity originating from disturbed neuropsychological functioning.
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218
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Amphetamine acts within the lateral hypothalamic area to elicit affectively neutral arousal and reinstate drug-seeking. Int J Neuropsychopharmacol 2014; 17:63-75. [PMID: 23895988 PMCID: PMC6150758 DOI: 10.1017/s1461145713000734] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Psychostimulants, including amphetamine (AMPH), exert robust arousal-enhancing, reinforcing and locomotor-activating effects. These behavioural actions involve drug-induced elevations in extracellular norepinephrine (NE) and dopamine (DA) within a variety of cortical and subcortical regions. The lateral hypothalamic area (LHA), including the lateral hypothalamus proper, perifornical area and adjacent dorsomedial hypothalamus, is implicated in appetitive- and arousal-related processes. The LHA is innervated by both NE and DA projections and systemically administered AMPH has been demonstrated to activate LHA neurons. Combined, these and other observations suggest the LHA may be a site of action in the behavioural effects of psychostimulants. To test this hypothesis, we examined the degree to which AMPH (10 nmol, 25 nmol) acts within the LHA to exert arousing, locomotor-activating and reinforcing actions in quietly resting/sleeping rats. Although intra-LHA AMPH robustly increased time spent awake, this occurred in the absence of pronounced locomotor activation or reinforcing actions, as measured in a conditioned place preference (CPP) paradigm. Arousing and stressful conditions or drug re-exposure can elicit relapse in humans and reinstate drug-seeking in animals. Given the LHA is also implicated in the reinstatement of drug-seeking behaviour, additional studies examined whether AMPH acts within the LHA to reinstate an extinguished CPP produced with systemic AMPH administration. Our results demonstrate that AMPH action within the LHA is sufficient to reinstate drug-seeking behaviour, as measured in this paradigm. Collectively, these observations demonstrate that psychostimulants act within the LHA to elicit affectively neutral arousal and reinstate drug-seeking behaviour.
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219
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Orexinergic input to dopaminergic neurons of the human ventral tegmental area. PLoS One 2013; 8:e83029. [PMID: 24376626 PMCID: PMC3869755 DOI: 10.1371/journal.pone.0083029] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 11/08/2013] [Indexed: 11/26/2022] Open
Abstract
The mesolimbic reward pathway arising from dopaminergic (DA) neurons of the ventral tegmental area (VTA) has been strongly implicated in reward processing and drug abuse. In rodents, behaviors associated with this projection are profoundly influenced by an orexinergic input from the lateral hypothalamus to the VTA. Because the existence and significance of an analogous orexigenic regulatory mechanism acting in the human VTA have been elusive, here we addressed the possibility that orexinergic neurons provide direct input to DA neurons of the human VTA. Dual-label immunohistochemistry was used and orexinergic projections to the VTA and to DA neurons of the neighboring substantia nigra (SN) were analyzed comparatively in adult male humans and rats. Orexin B-immunoreactive (IR) axons apposed to tyrosine hydroxylase (TH)-IR DA and to non-DA neurons were scarce in the VTA and SN of both species. In the VTA, 15.0±2.8% of TH-IR perikarya in humans and 3.2±0.3% in rats received orexin B-IR afferent contacts. On average, 0.24±0.05 and 0.05±0.005 orexinergic appositions per TH-IR perikaryon were detected in humans and rats, respectively. The majority (86–88%) of randomly encountered orexinergic contacts targeted the dendritic compartment of DA neurons. Finally, DA neurons of the SN also received orexinergic innervation in both species. Based on the observation of five times heavier orexinergic input to TH-IR neurons of the human, compared with the rat, VTA, we propose that orexinergic mechanism acting in the VTA may play just as important roles in reward processing and drug abuse in humans, as already established well in rodents.
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220
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Chen YW, Morganstern I, Barson JR, Hoebel BG, Leibowitz SF. Differential role of D1 and D2 receptors in the perifornical lateral hypothalamus in controlling ethanol drinking and food intake: possible interaction with local orexin neurons. Alcohol Clin Exp Res 2013; 38:777-86. [PMID: 24236888 DOI: 10.1111/acer.12313] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Accepted: 09/24/2013] [Indexed: 01/11/2023]
Abstract
BACKGROUND The neurotransmitter dopamine (DA), acting in various mesolimbic brain regions, is well known for its role in promoting motivated behaviors, including ethanol (EtOH) drinking. Indirect evidence, however, suggests that DA in the perifornical lateral hypothalamus (PF/LH) has differential effects on EtOH consumption, depending on whether it acts on the DA 1 (D1) or DA 2 (D2) receptor subtype, and that these effects are mediated in part by local peptide systems, such as orexin/hypocretin (OX) and melanin-concentrating hormone (MCH), known to stimulate the consumption of EtOH. METHODS The present study in brain-cannulated Sprague-Dawley rats measured the effects of dopaminergic compounds in the PF/LH on drinking behavior in animals trained to consume 7% EtOH and also on local peptide mRNA expression using digoxigenin-labeled in situ hybridization in EtOH-naïve animals. RESULTS Experiments 1 and 2 showed that the D1 agonist SKF81297 (10.8 nmol/side) in the PF/LH significantly increased food intake, while tending to increase EtOH intake, and the D1 antagonist SCH23390 significantly decreased EtOH intake without affecting food intake. In contrast, the D2 agonist quinelorane (6.2 nmol/side) in the PF/LH significantly reduced EtOH consumption, while the D2 antagonist sulpiride increased it. Experiments 3 and 4 revealed differential effects of PF/LH injection of the DA agonists on local OX mRNA, which was increased by the D1 agonist and decreased by the D2 agonist. These DA agonists had no impact on MCH expression. CONCLUSIONS These results support a stimulatory role of the PF/LH D1 receptor in promoting the consumption of both EtOH and food, in contrast to a suppressive effect of the D2 receptor on EtOH drinking. They further suggest that these receptors affect consumption, in part, through local OX-expressing neurons. These findings provide new evidence for the function of PF/LH DA receptor subtypes in controlling EtOH and food intake.
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Affiliation(s)
- Yu-Wei Chen
- Department of Psychology , Princeton University, Princeton, New Jersey; Laboratory of Behavioral Neurobiology , The Rockefeller University, New York, New York
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221
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Brom M, Both S, Laan E, Everaerd W, Spinhoven P. The role of conditioning, learning and dopamine in sexual behavior: a narrative review of animal and human studies. Neurosci Biobehav Rev 2013; 38:38-59. [PMID: 24211372 DOI: 10.1016/j.neubiorev.2013.10.014] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 10/22/2013] [Accepted: 10/29/2013] [Indexed: 12/24/2022]
Abstract
Many theories of human sexual behavior assume that sexual stimuli obtain arousing properties through associative learning processes. It is widely accepted that classical conditioning contributes to the etiology of both normal and maladaptive human behaviors. Despite the hypothesized importance of basic learning processes in sexual behavior, research on classical conditioning of the sexual response in humans is scarce. In the present paper, animal studies and studies in humans on the role of pavlovian conditioning on sexual responses are reviewed. Animal research shows robust, direct effects of conditioning processes on partner- and place preference. On the contrast, the empirical research with humans in this area is limited and earlier studies within this field are plagued by methodological confounds. Although recent experimental demonstrations of human sexual conditioning are neither numerous nor robust, sexual arousal showed to be conditionable in both men and women. The present paper serves to highlight the major empirical findings and to renew the insight in how stimuli can acquire sexually arousing value. Hereby also related neurobiological processes in reward learning are discussed. Finally, the connections between animal and human research on the conditionability of sexual responses are discussed, and suggestions for future directions in human research are given.
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Affiliation(s)
- Mirte Brom
- Institute of Psychology, Clinical, Health and Neuropsychology Unit, Leiden University, The Netherlands; Department of Psychosomatic Gynaecology and Sexology, Leiden University Medical Center, Leiden, The Netherlands.
| | - Stephanie Both
- Department of Psychosomatic Gynaecology and Sexology, Leiden University Medical Center, Leiden, The Netherlands
| | - Ellen Laan
- Department of Sexology and Psychosomatic Obstetrics and Gynaecology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Walter Everaerd
- Department Clinical Psychology, University of Amsterdam, Amsterdam, The Netherlands
| | - Philip Spinhoven
- Institute of Psychology, Clinical, Health and Neuropsychology Unit, Leiden University, The Netherlands; Department of Psychiatry, Leiden University Medical Center, The Netherlands
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222
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Haghparast A, Omranifard A, Arezoomandan R, Ghalandari-Shamami M, Taslimi Z, Vafaei AA, Rashidy-Pour A. Involvement of dopaminergic receptors of the rat nucleus accumbens in decreasing the conditioned place preference induced by lateral hypothalamus stimulation. Neurosci Lett 2013; 556:10-4. [DOI: 10.1016/j.neulet.2013.09.062] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 08/29/2013] [Accepted: 09/26/2013] [Indexed: 01/26/2023]
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223
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Qi K, Wei C, Li Y, Sui N. Orexin receptors within the nucleus accumbens shell mediate the stress but not drug priming-induced reinstatement of morphine conditioned place preference. Front Behav Neurosci 2013; 7:144. [PMID: 24133421 PMCID: PMC3794194 DOI: 10.3389/fnbeh.2013.00144] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Accepted: 09/24/2013] [Indexed: 01/17/2023] Open
Abstract
Orexins are found to participate in mediating stress-induced drug relapse. However, the neuroanatomical basis that orexin transmission modulates stress-induced drug seeking remains unknown. The nucleus accumbens shell (NAcSh), best known for its role in appetitive and negative motivation via dopamine receptors, is likely to be the potential important brain area where the orexin system mediates stress-induced drug relapse since the function of dopamine system in the NAcSh can be regulated by orexin transmission. In the present study, a morphine conditioned place preference (CPP) model was used to determine whether the two types of orexin receptors would be involved into footshock-induced and/or drug priming-induced CPP reinstatement differentially. The results showed that blockade of orexin-1 or orexin-2 receptor in the NAcSh significantly attenuated stress-induced morphine CPP reinstatement, but neither of the orexin antagonists had any effect on morphine priming-induced reinstatement. These findings indicate that the NAcSh is a brain area through which orexins participate in stress but not drug priming-induced relapse of opioid seeking.
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Affiliation(s)
- Keke Qi
- 1Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences Beijing, China ; 2Institute of Psychology, University of Chinese Academy of Sciences Beijing, China
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224
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Nakamura K. The role of the dorsal raphé nucleus in reward-seeking behavior. Front Integr Neurosci 2013; 7:60. [PMID: 23986662 PMCID: PMC3753458 DOI: 10.3389/fnint.2013.00060] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2013] [Accepted: 07/30/2013] [Indexed: 12/22/2022] Open
Abstract
Pharmacological experiments have shown that the modulation of brain serotonin levels has a strong impact on value-based decision making. Anatomical and physiological evidence also revealed that the dorsal raphé nucleus (DRN), a major source of serotonin, and the dopamine system receive common inputs from brain regions associated with appetitive and aversive information processing. The serotonin and dopamine systems also have reciprocal functional influences on each other. However, the specific mechanism by which serotonin affects value-based decision making is not clear. To understand the information carried by the DRN for reward-seeking behavior, we measured single neuron activity in the primate DRN during the performance of saccade tasks to obtain different amounts of a reward. We found that DRN neuronal activity was characterized by tonic modulation that was altered by the expected and received reward value. Consistent reward-dependent modulation across different task periods suggested that DRN activity kept track of the reward value throughout a trial. The DRN was also characterized by modulation of its activity in the opposite direction by different neuronal subgroups, one firing strongly for the prediction and receipt of large rewards, with the other firing strongly for small rewards. Conversely, putative dopamine neurons showed positive phasic responses to reward-indicating cues and the receipt of an unexpected reward amount, which supports the reward prediction error signal hypothesis of dopamine. I suggest that the tonic reward monitoring signal of the DRN, possibly together with its interaction with the dopamine system, reports a continuous level of motivation throughout the performance of a task. Such a signal may provide "reward context" information to the targets of DRN projections, where it may be integrated further with incoming motivationally salient information.
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Affiliation(s)
- Kae Nakamura
- Department of Physiology, Kansai Medical University Hirakata, Japan ; Precursory Research for Embryonic Science and Technology, Japan Science and Technology Agency Kawaguchi, Japan
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225
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Perrey DA, German NA, Gilmour BP, Li JX, Harris DL, Thomas BF, Zhang Y. Substituted tetrahydroisoquinolines as selective antagonists for the orexin 1 receptor. J Med Chem 2013; 56:6901-16. [PMID: 23941044 DOI: 10.1021/jm400720h] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Increasing evidence implicates the orexin 1 (OX1) receptor in reward processes, suggesting OX1 antagonism could be therapeutic in drug addiction. In a program to develop an OX1 selective antagonist, we designed and synthesized a series of substituted tetrahydroisoquinolines and determined their potency in OX1 and OX2 calcium mobilization assays. Structure-activity relationship (SAR) studies revealed limited steric tolerance and a preference for electron deficiency at the 7-position. Pyridylmethyl groups were shown to be optimal for activity at the acetamide position. Computational studies resulted in a pharmacophore model and confirmed the SAR results. Compound 72 significantly attenuated the development of place preference for cocaine in rats.
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Affiliation(s)
- David A Perrey
- Research Triangle Institute , Research Triangle Park, North Carolina 27709, United States
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226
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Orexins (hypocretins) contribute to fear and avoidance in rats exposed to a single episode of footshocks. Brain Struct Funct 2013; 219:2103-18. [PMID: 23955372 DOI: 10.1007/s00429-013-0626-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 08/07/2013] [Indexed: 12/18/2022]
Abstract
Orexins (hypocretins) are peptides that have been shown to regulate behavioral arousal and wakefulness. Recent evidence indicates that orexin neurons are activated by stress and that orexins play a role in anxiety. The present paper describes a series of experiments that examined whether orexins are involved in the anxiety that resulted from exposing rats to an acute episode of footshocks (5 × 2 s of 1.5 mA shocks). We found that prepro-orexin (ppOX) mRNA was elevated in rats at 6 and 14 days after exposure to footshock and that ppOX mRNA levels were correlated with fear at 14 days post-shock. Systemic injections of the non-selective dual orexin receptor antagonist TCS-1102 (10 and 20 mg/kg, i.p.) were found to decrease fear and anxiety in rats 14 days after exposure to footshock. We also found that rats that exhibited a high level of immobility to a novel tone the day after the footshock episode (high responders, HR) showed significantly elevated levels of ppOX mRNA at 14 days post-shock compared to control rats. Furthermore, TCS-1102 (10 mg/kg, i.p.) was found to have anxiolytic effects that were specific for HR when tested in the elevated T-maze. This study provides evidence linking the orexin system to the anxiety produced by exposure of rats to a single episode of footshocks. It also provides preclinical evidence in support of the use of orexin antagonists for the treatment of anxiety in response to an acute episode of stress.
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227
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An orexin hotspot in ventral pallidum amplifies hedonic 'liking' for sweetness. Neuropsychopharmacology 2013; 38:1655-64. [PMID: 23463152 PMCID: PMC3717533 DOI: 10.1038/npp.2013.62] [Citation(s) in RCA: 136] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Revised: 01/12/2013] [Accepted: 01/15/2013] [Indexed: 11/08/2022]
Abstract
Orexin (hypocretin) is implicated in stimulating appetite as well as arousal, and in both food reward and drug reward. The ventral pallidum (VP) receives orexin projections from lateral hypothalamus neurons (LH), and orexin terminals are especially dense in the posterior half of VP, which is also the location of an opioid hedonic hotspot. The VP hotspot is a roughly cubic-millimeter site where mu opioid stimulation can amplify the hedonic impact of sweetness, expressed as an increase in 'liking' reactions to sucrose taste. The anatomical overlap in posterior VP between opioid hotspot and orexin inputs raises the possibility that the hedonic hotspot might allow orexin to amplify 'liking' too. We examined whether microinjections of orexin-A into the VP hotspot enhance the hedonic impact of sucrose, as assessed via affective taste reactivity measures of 'liking' reactions, and additionally compared effects at nearby sites in adjacent LH and extended amygdala. Taste reactivity results indicated that orexin stimulation specifically in the VP hotspot nearly doubled the magnitude of positive 'liking' reactions elicited by the taste of sucrose. Mapping results for localization of function, aided by Fos plume measures of the local spread of orexin impact, suggested that hedonic enhancement was generated by essentially the same cubic-millimeter of posterior VP previously identified as the opioid hotspot. By contrast, microinjection sites in the anterior half of VP, or in LH or extended amygdala, generally failed to produce any hedonic enhancement. We conclude that an orexin hedonic hotspot exists in posterior VP, with similar boundaries to the opioid hotspot. An orexin hedonic hotspot may permit regulatory hypothalamic circuitry to make foods more 'liked' during hunger by acting through VP. Dysfunction in a VP orexin hotspot in addiction or mood disorders might also contribute to some types of affective psychopathology.
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228
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A role for hypocretin/orexin receptor-1 in cue-induced reinstatement of nicotine-seeking behavior. Neuropsychopharmacology 2013; 38:1724-36. [PMID: 23518606 PMCID: PMC3717542 DOI: 10.1038/npp.2013.72] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 03/04/2013] [Accepted: 03/18/2013] [Indexed: 01/01/2023]
Abstract
Hypocretin/orexin signaling is critically involved in relapse to drug-seeking behaviors. In this study, we investigated the involvement of the hypocretin system in the reinstatement of nicotine-seeking behavior induced by nicotine-associated cues. Pretreatment with the hypocretin receptor-1 antagonist SB334867, but not with the hypocretin receptor-2 antagonist TCSOX229, attenuated cue-induced reinstatement of nicotine-seeking, which was associated with an activation of hypocretin neurons of the lateral and perifornical hypothalamic areas. In addition, relapse to nicotine-seeking increased the phosphorylation levels of GluR2-Ser880, NR1-Ser890, and p38 MAPK in the nucleus accumbens (NAc), but not in the prefrontal cortex. Notably, phosphorylation levels of NR1-Ser890 and p38 MAPK, but not GluR2-Ser880, were dependent on hypocretin receptor-1 activation. The intra-accumbens infusion of the protein kinase C (PKC) inhibitor NPC-15437 reduced nicotine-seeking behavior elicited by drug-paired cues consistent with the PKC-dependent phosphorylations of GluR2-Ser880 and NR1-Ser890. SB334867 failed to modify cue-induced reinstatement of food-seeking, which did not produce any biochemical changes in the NAc. These data identify hypocretin receptor-1 and PKC signaling as potential targets for the treatment of relapse to nicotine-seeking induced by nicotine-associated cues.
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229
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Macedo GC, Kawakami SE, Vignoli T, Sinigaglia-Coimbra R, Suchecki D. The influence of orexins on ethanol-induced behavioral sensitization in male mice. Neurosci Lett 2013; 551:84-8. [PMID: 23880022 DOI: 10.1016/j.neulet.2013.07.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 06/28/2013] [Accepted: 07/10/2013] [Indexed: 01/27/2023]
Abstract
Recent evidence indicates the involvement of orexin in reward circuitry and drug addiction. In the present study we evaluated the role of orexin in ethanol-induced behavioral sensitization. In the first experiment, Swiss male mice received seven administrations of saline or ethanol (2.2g/kg, i.p., chronic), every other day. On the last day of treatment, half of saline-treated mice received a saline injection (saline) whereas the other half received 2.2g/kg of ethanol (i.p., acute). Behavioral sensitization was assessed by locomotor activity tests and after the last one, immunoreactivity for orexin and Fos (ORX+Fos-ir) was assessed in the lateral hypothalamic area. Chronic ethanol treatment produced behavioral sensitization and a trend for greater ORX+Fos-ir. In the second experiment, mice were treated as in Experiment 1 and type 1 orexin receptor antagonist, SB334867 (20mg/kg), was administered before the ethanol challenge successfully blocking the expression of sensitization in mice chronically treated with EtOH. These results indicate that orexin plays a role in ethanol-induced behavioral sensitization.
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230
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McNally GP. Extinction of drug seeking: Neural circuits and approaches to augmentation. Neuropharmacology 2013; 76 Pt B:528-32. [PMID: 23774135 DOI: 10.1016/j.neuropharm.2013.06.007] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 06/02/2013] [Accepted: 06/03/2013] [Indexed: 12/23/2022]
Abstract
Extinction training can reduce drug seeking behavior. This article reviews the neural circuits that contribute to extinction and approaches to enhancing the efficacy of extinction. Extinction of drug seeking depends on cortical-striatal-hypothalamic and cortical-hypothalamic-thalamic pathways. These pathways interface, in the hypothalamus and thalamus respectively, with the neural circuits controlling reinstatement of drug seeking. The actions of these pathways at lateral hypothalamic orexin neurons, and of perifornical/dorsomedial hypothalamic derived opioid peptides at kappa opioid receptors in the paraventricular thalamus, are important for inhibiting drug seeking. Despite effectively reducing or inhibiting drug seeking in the short term, extinguished drug seeking is prone to relapse. Three different strategies to augment extinction learning or retrieval are reviewed: pharmacological augmentation, retrieval - extinction training, and provision of extinction memory retrieval cues. These strategies have been used in animal models and with human drug users to enhance extinction or cue exposure treatments. They hold promise as novel strategies to promote abstinence from drug seeking. This article is part of a Special Issue entitled 'NIDA 40th Anniversary Issue'.
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Affiliation(s)
- Gavan P McNally
- The University of New South Wales, School of Psychology, Sydney, NSW 2052, Australia.
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231
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Boutrel B, Steiner N, Halfon O. The hypocretins and the reward function: what have we learned so far? Front Behav Neurosci 2013; 7:59. [PMID: 23781178 PMCID: PMC3680710 DOI: 10.3389/fnbeh.2013.00059] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 05/19/2013] [Indexed: 01/15/2023] Open
Abstract
A general consensus acknowledges that drug consumption (including alcohol, tobacco, and illicit drugs) constitutes the leading cause of preventable death worldwide. But the global burden of drug abuse extends the mortality statistics. Indeed, the comorbid long-term debilitating effects of the disease also significantly deteriorate the quality of life of individuals suffering from addiction disorders. Despite the large body of evidence delineating the cellular and molecular adaptations induced by chronic drug consumption, the brain mechanisms responsible for drug craving and relapse remain insufficiently understood, and even the most recent developments in the field have not brought significant improvement in the management of drug dependence. Though, recent preclinical evidence suggests that disrupting the hypocretin (orexin) system may serve as an anticraving medication therapy. Here, we discuss how the hypocretins, which orchestrate normal wakefulness, metabolic health and the execution of goal-oriented behaviors, may be compromised and contribute to elicit compulsive drug seeking. We propose an overview on the most recent studies demonstrating an important role for the hypocretin neuropeptide system in the regulation of drug reward and the prevention of drug relapse, and we question the relevance of disrupting the hypocretin system to alleviate symptoms of drug addiction.
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Affiliation(s)
- Benjamin Boutrel
- Department of Psychiatry, Center for Psychiatric Neuroscience, Lausanne University Hospital Lausanne, Switzerland ; Department of Psychiatry, Division of Child and Adolescent Psychiatry, Lausanne University Hospital Lausanne, Switzerland
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232
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Zarepour L, Komaki A, Shahidi S, Sarihi A, Haghparast A. Potentiation of rewarding properties of morphine by concurrent chemical stimulation of lateral hypothalamus in rats. Pharmacol Biochem Behav 2013; 107:36-41. [DOI: 10.1016/j.pbb.2013.03.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 03/16/2013] [Accepted: 03/30/2013] [Indexed: 12/18/2022]
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233
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Abstract
Depression is a devastating mental disorder with an increasing impact throughout the world, whereas the efficacy of currently available pharmacological treatment is still limited. Growing evidence from preclinical and clinical studies suggests that orexins (neuropeptides that are also known as hypocretins) and their receptors are involved in the physiopathology of depression. Indeed, the orexinergic system regulates functions that are disturbed in depressive states such as sleep, reward system, feeding behavior, the stress response and monoaminergic neurotransmission. Nevertheless, the precise role of orexins in behavioral and neurophysiological impairments observed in depression is still unclear. Both hypoactivity and hyperactivity of orexin signaling pathways have been found to be associated with depression. These discrepancies in the literature prompted the necessity for additional investigations, as the orexinergic system appears to be a promising target to treat the symptoms of depression. This assumption is underlined by recent data suggesting that pharmacological blockade of orexin receptors induces a robust antidepressant-like effect in an animal model of depression. Further preclinical and clinical studies are needed to progress the overall understanding of the orexinergic alterations in depression, which will eventually translate preliminary observations into real therapeutic potential. The aim of this paper is to provide an overview of human and animal research dedicated to the study of the specific involvement of orexins in depression, and to propose a framework in which disturbances of the orexinergic system are regarded as an integral component of the etiology of depression.
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Affiliation(s)
- Mathieu Nollet
- UMR Inserm 930-Imagerie et Cerveau, Equipe 4: Troubles Affectifs, Université François-Rabelais de Tours, UFR Sciences et Techniques, Parc Grandmont, 37200 Tours, France
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234
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Jiménez A, Caba M, Escobar C. Food-entrained patterns in orexin cells reveal subregion differential activation. Brain Res 2013; 1513:41-50. [DOI: 10.1016/j.brainres.2013.03.031] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Revised: 03/19/2013] [Accepted: 03/20/2013] [Indexed: 11/29/2022]
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235
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Fadel JR, Jolivalt CG, Reagan LP. Food for thought: the role of appetitive peptides in age-related cognitive decline. Ageing Res Rev 2013; 12:764-76. [PMID: 23416469 DOI: 10.1016/j.arr.2013.01.009] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2012] [Revised: 01/22/2013] [Accepted: 01/25/2013] [Indexed: 01/25/2023]
Abstract
Through their well described actions in the hypothalamus, appetitive peptides such as insulin, orexin and leptin are recognized as important regulators of food intake, body weight and body composition. Beyond these metabolic activities, these peptides also are critically involved in a wide variety of activities ranging from modulation of immune and neuroendocrine function to addictive behaviors and reproduction. The neurological activities of insulin, orexin and leptin also include facilitation of hippocampal synaptic plasticity and enhancement of cognitive performance. While patients with metabolic disorders such as obesity and diabetes have greater risk of developing cognitive deficits, dementia and Alzheimer's disease (AD), the underlying mechanisms that are responsible for, or contribute to, age-related cognitive decline are poorly understood. In view of the importance of these peptides in metabolic disorders, it is not surprising that there is a greater focus on their potential role in cognitive deficits associated with aging. The goal of this review is to describe the evidence from clinical and pre-clinical studies implicating insulin, orexin and leptin in the etiology and progression of age-related cognitive decline. Collectively, these studies support the hypothesis that leptin and insulin resistance, concepts normally associated with the hypothalamus, are also applicable to the hippocampus.
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Affiliation(s)
- Jim R Fadel
- Department of Pharmacology, Physiology and Neuroscience, School of Medicine, University of South Carolina, 6439 Garners Ferry Road, Columbia, SC 29208, USA
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236
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Nieh EH, Kim SY, Namburi P, Tye KM. Optogenetic dissection of neural circuits underlying emotional valence and motivated behaviors. Brain Res 2013; 1511:73-92. [PMID: 23142759 PMCID: PMC4099056 DOI: 10.1016/j.brainres.2012.11.001] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2012] [Revised: 11/01/2012] [Accepted: 11/02/2012] [Indexed: 12/26/2022]
Abstract
The neural circuits underlying emotional valence and motivated behaviors are several synapses away from both defined sensory inputs and quantifiable motor outputs. Electrophysiology has provided us with a suitable means for observing neural activity during behavior, but methods for controlling activity for the purpose of studying motivated behaviors have been inadequate: electrical stimulation lacks cellular specificity and pharmacological manipulation lacks temporal resolution. The recent emergence of optogenetic tools provides a new means for establishing causal relationships between neural activity and behavior. Optogenetics, the use of genetically-encodable light-activated proteins, permits the modulation of specific neural circuit elements with millisecond precision. The ability to control individual cell types, and even projections between distal regions, allows us to investigate functional connectivity in a causal manner. The greatest consequence of controlling neural activity with finer precision has been the characterization of individual neural circuits within anatomical brain regions as defined functional units. Within the mesolimbic dopamine system, optogenetics has helped separate subsets of dopamine neurons with distinct functions for reward, aversion and salience processing, elucidated GABA neuronal effects on behavior, and characterized connectivity with forebrain and cortical structures. Within the striatum, optogenetics has confirmed the opposing relationship between direct and indirect pathway medium spiny neurons (MSNs), in addition to characterizing the inhibition of MSNs by cholinergic interneurons. Within the hypothalamus, optogenetics has helped overcome the heterogeneity in neuronal cell-type and revealed distinct circuits mediating aggression and feeding. Within the amygdala, optogenetics has allowed the study of intra-amygdala microcircuitry as well as interconnections with distal regions involved in fear and anxiety. In this review, we will present the body of optogenetic studies that has significantly enhanced our understanding of emotional valence and motivated behaviors. This article is part of a Special Issue entitled Optogenetics (7th BRES).
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Affiliation(s)
- Edward H. Nieh
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Sung-Yon Kim
- Department of Bioengineering, Neurosciences Program, Stanford University, Stanford, CA, USA
| | - Praneeth Namburi
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Kay M. Tye
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
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237
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Chiu CN, Prober DA. Regulation of zebrafish sleep and arousal states: current and prospective approaches. Front Neural Circuits 2013; 7:58. [PMID: 23576957 PMCID: PMC3620505 DOI: 10.3389/fncir.2013.00058] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Accepted: 03/14/2013] [Indexed: 01/20/2023] Open
Abstract
Every day, we shift among various states of sleep and arousal to meet the many demands of our bodies and environment. A central puzzle in neurobiology is how the brain controls these behavioral states, which are essential to an animal's well-being and survival. Mammalian models have predominated sleep and arousal research, although in the past decade, invertebrate models have made significant contributions to our understanding of the genetic underpinnings of behavioral states. More recently, the zebrafish has emerged as a promising model system for sleep and arousal research. Here we review experimental evidence that the zebrafish, a diurnal vertebrate, exhibits fundamental behavioral and neurochemical characteristics of mammalian sleep and arousal. We also propose how specific advantages of the zebrafish can be harnessed to advance the field. These include tractable genetics to identify and manipulate molecular and cellular regulators of behavioral states, optical transparency to facilitate in vivo observation of neural structure and function, and amenability to high-throughput drug screens to discover novel therapies for neurological disorders.
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Affiliation(s)
| | - David A. Prober
- Division of Biology, California Institute of TechnologyPasadena, CA, USA
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238
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Petrovich GD. Forebrain networks and the control of feeding by environmental learned cues. Physiol Behav 2013; 121:10-8. [PMID: 23562305 DOI: 10.1016/j.physbeh.2013.03.024] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Accepted: 03/06/2013] [Indexed: 01/23/2023]
Abstract
The motivation to eat is driven by a complex sum of physiological and non-physiological influences computed by the brain. Physiological signals that inform the brain about energy and nutrient needs are the primary drivers, but environmental signals unrelated to energy balance also control appetite and eating. The two components could act in concert to support the homeostatic regulation of food intake. Often, however, environmental influences rival physiological control and stimulate eating irrespective of satiety, or inhibit eating irrespective of hunger. If persistent, such maladaptive challenges to the physiological system could lead to dysregulated eating and ultimately to eating disorders. Nevertheless, the brain mechanisms underlying environmental contribution in the control of food intake are poorly understood. This paper provides an overview in recent advances in deciphering the critical brain systems using rodent models for environmental control by learned cues. These models use associative learning to compete with the physiological control, and in one preparation food cues stimulate a meal despite satiety, while in another preparation fear cues stop a meal despite hunger. Thus far, four forebrain regions have been identified as part of the essential cue induced feeding circuitry. These are telencephalic areas critical for associative learning, memory encoding, and decision making, the amygdala, hippocampus and prefrontal cortex and the lateral hypothalamus, which functions to integrate feeding, reward, and motivation. This circuitry also engages two orexigenic peptides, ghrelin and orexin. A parallel amygdalar circuitry supports fear cue cessation of feeding. These findings illuminate the brain mechanisms underlying environmental control of food intake and might be also relevant to aspects of human appetite and maladaptive overeating and undereating.
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Affiliation(s)
- Gorica D Petrovich
- Department of Psychology, Boston College, Chestnut Hill, MA, United States.
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239
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Interactions between VTA orexin and glutamate in cue-induced reinstatement of cocaine seeking in rats. Psychopharmacology (Berl) 2013; 226:687-98. [PMID: 22411428 PMCID: PMC3649073 DOI: 10.1007/s00213-012-2681-5] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Accepted: 02/24/2012] [Indexed: 02/04/2023]
Abstract
RATIONALE Glutamate and orexin/hypocretin systems are involved in Pavlovian cue-triggered drug seeking. OBJECTIVES Here, we asked whether orexin and glutamate interact within ventral tegmental area (VTA) to promote reinstatement of extinguished cocaine seeking in a rat self-administration paradigm. METHODS/RESULTS We first found that bilateral VTA microinjections of the orexin 1 receptor (OX1R) antagonist SB-334867 (SB) or a cocktail of the AMPA and NMDA glutamate receptor antagonists CNQX/AP-5 reduced reinstatement of cocaine seeking elicited by cues. In contrast, neither of these microinjections nor systemic SB reduced cocaine-primed reinstatement. Additionally, unilateral VTA OX1R blockade combined with contralateral VTA glutamate blockade attenuated cue-induced reinstatement, indicating that VTA orexin and glutamate are simultaneously necessary for cue-induced reinstatement. We further probed the receptor specificity of glutamate actions in VTA, finding that CNQX, but not AP-5, dose-dependently attenuated cue-induced reinstatement, indicating that AMPA but not NMDA receptor transmission is required for this type of cocaine seeking. Given the necessary roles of both OX1 and AMPA receptors in VTA for cue-induced cocaine seeking, we hypothesized that these signaling pathways interact during this behavior. We found that PEPA, a positive allosteric modulator of AMPA receptors, completely reversed the SB-induced attenuation of reinstatement behavior. Intra-VTA PEPA alone did not alter cue-induced reinstatement, indicating that potentiating AMPA activity with this drug specifically compensates for OX1R blockade, rather than simply inducing or enhancing reinstatement itself. CONCLUSIONS These findings show that cue-induced, but not cocaine-primed, reinstatement of cocaine seeking is dependent upon orexin and AMPA receptor interactions in VTA.
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240
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Cason AM, Aston-Jones G. Role of orexin/hypocretin in conditioned sucrose-seeking in rats. Psychopharmacology (Berl) 2013; 226:155-65. [PMID: 23096770 PMCID: PMC3572270 DOI: 10.1007/s00213-012-2902-y] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Accepted: 09/27/2012] [Indexed: 11/30/2022]
Abstract
RATIONALE The orexin/hypocretin system has recently been implicated in reward-seeking, especially for highly salient food and drug rewards. We reasoned that this system may be strongly engaged during periods of reward restriction, including food restriction. OBJECTIVES This study examined the involvement of the orexin (Orx) system in responding for sucrose, and in cue-induced reinstatement of extinguished sucrose-seeking, in ad libitum fed versus food-restricted male subjects. METHODS Sprague-Dawley rats (n = 108) were trained to self-administer sucrose, and we determined the effects of pretreatment with the OxR1 receptor antagonist SB-334867 (SB; 10-30 mg/kg) on fixed ratio (FR) or progressive ratio (PR) sucrose self-administration, as well as on cue-induced reinstatement of sucrose-seeking. Finally, expression of the immediate early gene c-fos in Orx neurons was examined after self-administration, late extinction or cue-induced reinstatement of sucrose seeking. RESULTS SB decreased lever responding (by about 1/3) and the number of reinforcers earned during FR, and less so during PR, schedules and decreased cue-induced reinstatement to sucrose-seeking to extinction levels, predominately in food-restricted rats. Additionally, Fos expression in Orx neurons in perifornical and dorsomedial hypothalamus was increased during extinction. CONCLUSIONS These results indicate that signaling at the OxR1 receptor is involved in pronounced sucrose reinforcement, and reinstatement of sucrose-seeking elicited by sucrose-paired cues, in food-restricted subjects. These findings lead us to conclude that conditioned activation of Orx neurons increases motivation for food reward during food restriction.
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Affiliation(s)
- Angie M Cason
- Department of Neurosciences, Medical University of South Carolina, Basic Science Building 406, 173 Ashley Avenue, MSC 510, Charleston, SC 29425, USA
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241
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Gong Y, Wang D, Zhang X, Qu Z, Liu P, Zou H. The potential biological mechanisms of obesity effects on depression: A systematic review of the literature and knowledge mining. Health (London) 2013. [DOI: 10.4236/health.2013.511244] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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242
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Srinivasan S, Shariff M, Bartlett SE. The role of the glucocorticoids in developing resilience to stress and addiction. Front Psychiatry 2013; 4:68. [PMID: 23914175 PMCID: PMC3730062 DOI: 10.3389/fpsyt.2013.00068] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2013] [Accepted: 06/28/2013] [Indexed: 12/12/2022] Open
Abstract
There is emerging evidence that individuals have the capacity to learn to be resilient by developing protective mechanisms that prevent them from the maladaptive effects of stress that can contribute to addiction. The emerging field of the neuroscience of resilience is beginning to uncover the circuits and molecules that protect against stress-related neuropsychiatric diseases, such as addiction. Glucocorticoids (GCs) are important regulators of basal and stress-related homeostasis in all higher organisms and influence a wide array of genes in almost every organ and tissue. GCs, therefore, are ideally situated to either promote or prevent adaptation to stress. In this review, we will focus on the role of GCs in the hypothalamic-pituitary adrenocortical axis and extra-hypothalamic regions in regulating basal and chronic stress responses. GCs interact with a large number of neurotransmitter and neuropeptide systems that are associated with the development of addiction. Additionally, the review will focus on the orexinergic and cholinergic pathways and highlight their role in stress and addiction. GCs play a key role in promoting the development of resilience or susceptibility and represent important pharmacotherapeutic targets that can reduce the impact of a maladapted stress system for the treatment of stress-induced addiction.
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Affiliation(s)
- Subhashini Srinivasan
- Ernest Gallo Clinic and Research Center at the University of California San Francisco , Emeryville, CA , USA
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243
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Erami E, Azhdari-Zarmehri H, Rahmani A, Ghasemi-Dashkhasan E, Semnanian S, Haghparast A. Blockade of orexin receptor 1 attenuates the development of morphine tolerance and physical dependence in rats. Pharmacol Biochem Behav 2012; 103:212-9. [DOI: 10.1016/j.pbb.2012.08.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Revised: 08/12/2012] [Accepted: 08/15/2012] [Indexed: 11/30/2022]
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244
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Abstract
Vital hypothalamic neurons regulating hunger, wakefulness, reward-seeking, and body weight are often defined by unique expression of hypothalamus-specific neuropeptides. Gene-ablation studies show that some of these peptides, notably orexin/hypocretin (hcrt/orx), are themselves critical for stable states of consciousness and metabolic health. However, neuron-ablation studies often reveal more severe phenotypes, suggesting key roles for co-expressed transmitters. Indeed, most hypothalamic neurons, including hcrt/orx cells, contain fast transmitters glutamate and GABA, as well as several neuropeptides. What are the roles and relations between different transmitters expressed by the same neuron? Here, we consider signaling codes for releasing different transmitters in relation to transmitter and receptor diversity in behaviorally defined, widely projecting “peptidergic” neurons, such as hcrt/orx cells. We then discuss latest optogenetic studies of endogenous transmitter release from defined sets of axons in situ, which suggest that recently characterized vital peptidergic neurons [e.g., hcrt/orx, proopiomelanocortin (POMC), and agouti-related peptide (AgRP) cells], as well as classical modulatory neurons (e.g., dopamine and acetylcholine cells), all use fast transmitters to control their postsynaptic targets. These optogenetic insights are complemented by recent observations of behavioral deficiencies caused by genetic ablation of fast transmission from specific neuropeptidergic and aminergic neurons. Powerful and fast (millisecond-scale) GABAergic and glutamatergic signaling from neurons previously considered to be primarily “modulatory” raises new questions about the roles of slower co-transmitters they co-express.
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245
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Kim AK, Brown RM, Lawrence AJ. The role of orexins/hypocretins in alcohol use and abuse: an appetitive-reward relationship. Front Behav Neurosci 2012. [PMID: 23189046 PMCID: PMC3504295 DOI: 10.3389/fnbeh.2012.00078] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Orexins (hypocretins) are neuropeptides synthesized in neurons located in the lateral (LH), perifornical, and dorsomedial (DMH) hypothalamus. These neurons innervate many regions in the brain and modulate multiple other neurotransmitter systems. As a result of these extensive projections and interactions orexins are involved in numerous functions, such as feeding behavior, neuroendocrine regulation, the sleep-wake cycle, and reward-seeking. This review will summarize the literature to date which has evaluated a role of orexins in the behavioral effects of alcohol, with a focus on understanding the importance of this peptide and its potential as a clinical therapeutic target for alcohol use disorders.
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Affiliation(s)
- Andrezza K Kim
- Addiction Neuroscience Laboratory, Behavioural Neuroscience Division, Florey Neuroscience Institutes, University of Melbourne Parkville, VIC, Australia ; Departamento de Psicobiologia, Escola Paulista de Medicina, Universidade Federal de São Paulo São Paulo, Brazil
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Bell MR, De Lorme KC, Figueira RJ, Kashy DA, Sisk CL. Adolescent gain in positive valence of a socially relevant stimulus: engagement of the mesocorticolimbic reward circuitry. Eur J Neurosci 2012; 37:457-68. [PMID: 23173754 DOI: 10.1111/ejn.12058] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Revised: 10/12/2012] [Accepted: 10/16/2012] [Indexed: 01/01/2023]
Abstract
A successful transition from childhood to adulthood requires adolescent maturation of social information processing. The neurobiological underpinnings of this maturational process remain elusive. This research employed the male Syrian hamster as a tractable animal model for investigating the neural circuitry involved in this critical transition. In this species, adult and juvenile males display different behavioral and neural responses to vaginal secretions, which contain pheromones essential for expression of sexual behavior in adulthood. These studies tested the hypothesis that vaginal secretions acquire positive valence over adolescent development via remodeling of neural circuits underlying sexual reward. Sexually naïve adult, but not juvenile, hamsters showed a conditioned place preference for vaginal secretions. Differences in behavioral response to vaginal secretions between juveniles and adults correlated with a difference in the vaginal secretion-induced neural activation pattern in mesocorticolimbic reward circuitry. Fos immunoreactivity increased in response to vaginal secretions in the medial amygdala and ventral tegmental dopaminergic cells of both juvenile and adult males. However, only in adults was there a Fos response to vaginal secretions in non-dopaminergic cells in interfascicular ventral tegmental area, nucleus accumbens core and infralimbic medial prefrontal cortex. These results demonstrate that a socially relevant chemosensory stimulus acquires the status of an unconditioned reward during adolescence, and that this adolescent gain in social reward is correlated with experience-independent engagement of specific cell groups in reward circuitry.
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Affiliation(s)
- Margaret R Bell
- Neuroscience Program, Michigan State University, East Lansing, MI, USA.
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247
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Feng XM, Mi WL, Xia F, Mao-Ying QL, Jiang JW, Xiao S, Wang ZF, Wang YQ, Wu GC. Involvement of spinal orexin A in the electroacupuncture analgesia in a rat model of post-laparotomy pain. Altern Ther Health Med 2012; 12:225. [PMID: 23173601 PMCID: PMC3577429 DOI: 10.1186/1472-6882-12-225] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Accepted: 10/25/2012] [Indexed: 11/10/2022]
Abstract
BACKGROUND Orexin A (OXA, hypocretin/hcrt 1) is a newly discovered potential analgesic substance. However, whether OXA is involved in acupuncture analgesia remains unknown. The present study was designed to investigate the involvement of spinal OXA in electroacupuncture (EA) analgesia. METHODS A modified rat model of post-laparotomy pain was adopted and evaluated. Von Frey filaments were used to measure mechanical allodynia of the hind paw and abdomen. EA at 2/15 Hz or 2/100 Hz was performed once on the bilateral ST36 and SP6 for 30 min perioperatively. SB-334867, a selective orexin 1 receptor (OX1R) antagonist with a higher affinity for OXA than OXB, was intrathecally injected to observe its effect on EA analgesia. RESULTS OXA at 0.3 nmol and EA at 2/15 Hz produced respective analgesic effects on the model (P<0.05). Pre-surgical intrathecal administered of SB-334867 30 nmol antagonized OXA analgesia and attenuated the analgesic effect of EA (P<0.05). However, SB-334867 did not block fentanyl-induced analgesia (P>0.05). In addition, naloxone, a selective opioid receptor antagonist, failed to antagonize OXA-induced analgesia (P>0.05). CONCLUSIONS The results of the present study indicate the involvement of OXA in EA analgesia via OX1R in an opioid-independent way.
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248
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Iigaya K, Horiuchi J, McDowall LM, Lam ACB, Sediqi Y, Polson JW, Carrive P, Dampney RAL. Blockade of orexin receptors with Almorexant reduces cardiorespiratory responses evoked from the hypothalamus but not baro- or chemoreceptor reflex responses. Am J Physiol Regul Integr Comp Physiol 2012; 303:R1011-22. [DOI: 10.1152/ajpregu.00263.2012] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Orexin neurons form a restricted group in the dorsal hypothalamus. The group is centered on the perifornical area within the classic hypothalamic defense area, an area which when activated produces marked cardiovascular and respiratory effects. Central administration of orexin can produce cardiorespiratory effects, but the extent to which orexin contributes to such responses evoked from the perifornical hypothalamus is not clear. To determine this, we used the dual orexin receptor antagonist Almorexant to challenge the cardiorespiratory effects evoked by disinhibition of the perifornical hypothalamus. Bicuculline (10 and 20 pmol) was microinjected in the perifornical area before and after administration of Almorexant (15 mg/kg iv) or vehicle in urethane-anesthetized rats. Almorexant significantly reduced the pressor, tachycardic, renal sympathoexcitatory, and tachypneic responses to bicuculline (10 pmol, by 55%, 53%, 28%, 77%; 20 pmol, by 54%, 27%, 51%, 72%, respectively). Reductions of similar magnitude were observed with bicuculline microinjections centered on more caudal sites just peripheral to the orexin neuron group, which would likely have activated fewer orexin neurons. In contrast, Almorexant had no effect on the cardiorespiratory response of the chemoreflex (sodium cyanide injection) or the sympathetic component of the baroreflex. Thus orexin makes a major contribution to the cardiorespiratory response evoked from the perifornical area even though orexin neurons represent only a fraction of the output of this area. Orexin neurons may also mediate cardiorespiratory responses from non-orexin neurons in the caudal hypothalamus. However, under resting conditions, blockade of orexin receptors does not affect the chemo- and baroreflexes.
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Affiliation(s)
- Kamon Iigaya
- School of Medical Sciences and Bosch Institute for Biomedical Research, University of Sydney, New South Wales, Australia; and
| | - Jouji Horiuchi
- School of Medical Sciences and Bosch Institute for Biomedical Research, University of Sydney, New South Wales, Australia; and
| | - Lachlan M. McDowall
- School of Medical Sciences and Bosch Institute for Biomedical Research, University of Sydney, New South Wales, Australia; and
| | - Alex C. B. Lam
- School of Medical Sciences and Bosch Institute for Biomedical Research, University of Sydney, New South Wales, Australia; and
| | - Yusuf Sediqi
- School of Medical Sciences and Bosch Institute for Biomedical Research, University of Sydney, New South Wales, Australia; and
| | - Jaimie W. Polson
- School of Medical Sciences and Bosch Institute for Biomedical Research, University of Sydney, New South Wales, Australia; and
| | - Pascal Carrive
- School of Medical Sciences, University of New South Wales, New South Wales, Australia
| | - Roger A. L. Dampney
- School of Medical Sciences and Bosch Institute for Biomedical Research, University of Sydney, New South Wales, Australia; and
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249
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Martin-Fardon R, Boutrel B. Orexin/hypocretin (Orx/Hcrt) transmission and drug-seeking behavior: is the paraventricular nucleus of the thalamus (PVT) part of the drug seeking circuitry? Front Behav Neurosci 2012; 6:75. [PMID: 23162448 PMCID: PMC3494007 DOI: 10.3389/fnbeh.2012.00075] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Accepted: 10/19/2012] [Indexed: 11/17/2022] Open
Abstract
The orexin/hypocretin (Orx/Hcrt) system has long been considered to regulate a wide range of physiological processes, including feeding, energy metabolism, and arousal. More recently, concordant observations have demonstrated an important role for these peptides in the reinforcing properties of most drugs of abuse. Orx/Hcrt neurons arise in the lateral hypothalamus (LH) and project to all brain structures implicated in the regulation of arousal, stress, and reward. Although Orx/Hcrt neurons have been shown to massively project to the paraventricular nucleus of the thalamus (PVT), only recent evidence suggested that the PVT may be a key relay of Orx/Hcrt-coded reward-related communication between the LH and both the ventral and dorsal striatum. While this thalamic region was not thought to be part of the “drug addiction circuitry,” an increasing amount of evidence demonstrated that the PVT—particularly PVT Orx/Hcrt transmission—was implicated in the modulation of reward function in general and several aspects of drug-directed behaviors in particular. The present review discusses recent findings that suggest that maladaptive recruitment of PVT Orx/Hcrt signaling by drugs of abuse may promote persistent compulsive drug-seeking behavior following a period of protracted abstinence and as such may represent a relevant target for understanding the long-term vulnerability to drug relapse after withdrawal.
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Affiliation(s)
- Rémi Martin-Fardon
- Molecular and Integrative Neurosciences Department, The Scripps Research Institute La Jolla, CA, USA
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250
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Sartor GC, Aston-Jones G. Regulation of the ventral tegmental area by the bed nucleus of the stria terminalis is required for expression of cocaine preference. Eur J Neurosci 2012; 36:3549-58. [PMID: 23039920 DOI: 10.1111/j.1460-9568.2012.08277.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Revised: 07/31/2012] [Accepted: 08/03/2012] [Indexed: 01/23/2023]
Abstract
Lateral hypothalamus (LH) orexin neurons are essential for the expression of a cocaine place preference. However, the afferents that regulate the activity of these orexin neurons during reward behaviors are not completely understood. Using tract tracing combined with Fos staining, we examined LH afferents for Fos induction during cocaine preference in rats. We found that the ventral bed nucleus of the stria terminalis (vBNST) was a major input to the LH orexin cell field that was significantly Fos-activated during cocaine conditioned place preference (CPP). Inactivation of the vBNST with baclofen plus muscimol blocked expression of cocaine CPP. Surprisingly, such inactivation of the vBNST also increased Fos induction in LH orexin neurons; as activity in these cells is normally associated with increased preference, this result indicates that a vBNST-orexin connection is unlikely to be responsible for CPP that is dependent on vBNST activity. Because previous studies have revealed that vBNST regulates dopamine cells in the ventral tegmental area (VTA), which is known to be involved in CPP and other reward functions, we tested whether vBNST afferents to the VTA are necessary for cocaine CPP. We found that disconnection of the vBNST and VTA (using local microinjections of baclofen plus muscimol unilaterally into the vBNST and contralateral VTA) significantly attenuated expression of cocaine preference. However, blocking ionotropic glutamatergic afferents to the VTA from the vBNST did not significantly reduce cocaine preference. These results indicate that a non-glutamatergic vBNST-VTA projection is involved in expression of cocaine preference.
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Affiliation(s)
- Gregory C Sartor
- Department of Neurosciences, Medical University of South Carolina, 171 Ashley Avenue, BSB 403, Charleston, SC 29425, USA
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