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Salguero A, Marengo L, Cendán CM, Morón I, Ruiz-Leyva L, Pautassi RM. Ethanol drinking at adulthood is sensitive to S1-R antagonism and is promoted by binge ethanol self-administration at adolescence. Drug Alcohol Depend 2024; 260:111338. [PMID: 38838478 DOI: 10.1016/j.drugalcdep.2024.111338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2024] [Revised: 04/25/2024] [Accepted: 05/08/2024] [Indexed: 06/07/2024]
Abstract
BACKGROUND Binge drinking at adolescence is a risk factor for problematic alcohol (ethanol) consumption later in life, yet the murine studies that modelled this phenomenon via ethanol self-administration have provided mixed findings. Antagonism of the sigma-1 receptor (S1-R) system at adolescence modulates ethanol's motivational effects and intake. It is still unknown, however, whether this antagonism would protect against enhanced ethanol intake at adulthood after adolescent binge ethanol exposure. METHODS Exp. 1 and 2 tested adults male or female Wistar rats -exposed or not to ethanol self-administration at adolescence (postnatal days 31-49; nine 2-hour sessions of access to 8-10% ethanol)- for ethanol intake using 24-h two-bottle choice test (Exp. 1) or time restricted, single-bottle, tests (Exp. 2). Experiments 2-5 evaluated, in adolescent or adult rats, the effects of the S1-R antagonist S1RA on ethanol intake and on ethanol-induced conditioned taste or place aversion. Ancillary tests (e.g., novel object recognition, ethanol-induced locomotor activity) were also conducted. RESULTS Adolescent ethanol exposure promoted ethanol consumption at both the restricted, single-bottle, and at the two-bottle choice tests conducted at adulthood. S1RA administration reduced ethanol intake at adulthood and facilitated the development of ethanol-induced taste (but not place) aversion. CONCLUSIONS S1RA holds promise for lessening ethanol intake after chronic and substantial ethanol exposure in adolescence that results in heightened ethanol exposure at adulthood. This putative protective effect of S1-R antagonism may relate to S1RA exacerbating the aversive effects of this drug.
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Affiliation(s)
- Agustín Salguero
- Instituto de Investigación Médica M. y M. Ferreyra, INIMEC-CONICET, Universidad Nacional de Córdoba, Córdoba C.P. 5000, Argentina
| | - Leonardo Marengo
- Instituto de Investigación Médica M. y M. Ferreyra, INIMEC-CONICET, Universidad Nacional de Córdoba, Córdoba C.P. 5000, Argentina
| | - Cruz Miguel Cendán
- Department of Pharmacology, Institute of Neuroscience, Biomedical Research Center (CIBM) Faculty of Medicine, University of Granada and Biosanitary Research Institute ibs.GRANADA, Granada, Spain.
| | - Ignacio Morón
- Deparment of Psychobiology. Center of Research, Mind, Brain and Behabior (CIMCYC). University of Granada, Granada, Spain
| | - Leandro Ruiz-Leyva
- Department of Pharmacology, Institute of Neuroscience, Biomedical Research Center (CIBM) Faculty of Medicine, University of Granada and Biosanitary Research Institute ibs.GRANADA, Granada, Spain; Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Ricardo Marcos Pautassi
- Instituto de Investigación Médica M. y M. Ferreyra, INIMEC-CONICET, Universidad Nacional de Córdoba, Córdoba C.P. 5000, Argentina; Facultad de Psicología, Universidad Nacional de Córdoba, Córdoba C.P. 5000, Argentina.
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Knowles LG, Armanious AJ, Peng Y, Welsh WJ, James MH. Recent advances in drug discovery efforts targeting the sigma 1 receptor system: Implications for novel medications designed to reduce excessive drug and food seeking. ADDICTION NEUROSCIENCE 2023; 8:100126. [PMID: 37753198 PMCID: PMC10519676 DOI: 10.1016/j.addicn.2023.100126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/28/2023]
Abstract
Psychiatric disorders characterized by uncontrolled reward seeking, such as substance use disorders (SUDs), alcohol use disorder (AUD) and some eating disorders, impose a significant burden on individuals and society. Despite their high prevalence and substantial morbidity and mortality rates, treatment options for these disorders remain limited. Over the past two decades, there has been a gradual accumulation of evidence pointing to the sigma-1 receptor (S1R) system as a promising target for therapeutic interventions designed to treat these disorders. S1R is a chaperone protein that resides in the endoplasmic reticulum, but under certain conditions translocates to the plasma membrane. In the brain, S1Rs are expressed in several regions important for reward, and following translocation, they physically associate with several reward-related GPCRs, including dopamine receptors 1 and 2 (D1R and D2R). Psychostimulants, alcohol, as well as palatable foods, all alter expression of S1R in regions important for motivated behavior, and S1R antagonists generally decrease behavioral responses to these rewards. Recent advances in structural modeling have permitted the development of highly-selective S1R antagonists with favorable pharmacokinetic profiles, thus providing a therapeutic avenue for S1R-based medications. Here, we provide an up-to-date overview of work linking S1R with motivated behavior for drugs of abuse and food, as well as evidence supporting the clinical utility of S1R antagonists to reduce their excessive consumption. We also highlight potential challenges associated with targeting the S1R system, including the need for a more comprehensive understanding of the underlying neurobiology and careful consideration of the pharmacological properties of S1R-based drugs.
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Affiliation(s)
- Liam G. Knowles
- Harpur School of Arts and Sciences, Binghamton University, Vestal, NY, USA
| | - Abanoub J. Armanious
- Department of Psychiatry, Robert Wood Johnson Medical School, Rutgers University and Rutgers Biomedical Health Sciences, Piscataway, NJ, USA
- Brain Health Institute, Rutgers University and Rutgers Biomedical and Health Sciences, Piscataway, NJ, USA
| | - Youyi Peng
- Cancer Institute of New Jersey, Rutgers University, New Brunswick, NJ, USA
| | - William J. Welsh
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers University and Rutgers Biomedical Health Sciences, Piscataway, NJ, USA
| | - Morgan H. James
- Department of Psychiatry, Robert Wood Johnson Medical School, Rutgers University and Rutgers Biomedical Health Sciences, Piscataway, NJ, USA
- Brain Health Institute, Rutgers University and Rutgers Biomedical and Health Sciences, Piscataway, NJ, USA
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The Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) System of the Central Amygdala Mediates the Detrimental Effects of Chronic Social Defeat Stress in Rats. eNeuro 2022; 9:ENEURO.0260-22.2022. [PMID: 36566434 PMCID: PMC9506682 DOI: 10.1523/eneuro.0260-22.2022] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 07/28/2022] [Accepted: 08/12/2022] [Indexed: 01/21/2023] Open
Abstract
Many psychiatric diseases stem from an inability to cope with stressful events, as chronic stressors can precipitate or exacerbate psychopathologies. The neurobiological mechanisms underlying the response to chronic stress and the resulting anxiety states remain poorly understood. Stress neuropeptides in the extended amygdala circuitry mediate the behavioral response to stress, and hyperactivity of these systems has been hypothesized to be responsible for the emergence of persistent negative outcomes and for the pathogenesis of anxiety-related and trauma-related disorders. Pituitary adenylate cyclase-activating polypeptide (PACAP) and its receptor PAC1R are highly expressed within the central amygdala (CeA) and play a key role in stress regulation. Here, we used chronic social defeat stress (CSDS), a clinically relevant model of psychosocial stress that produces robust maladaptive behaviors in rodents. We found that 10 days of CSDS cause a significant increase in PACAP levels selectively in the CeA of rats, as well as an increase in PAC1R mRNA. Using a viral vector strategy, we found that PAC1R knock-down in the CeA attenuates the CSDS-induced body weight loss and prevents the CSDS-induced increase in anxiety-like behavior. Notably, CSDS animals display reduced basal corticosterone (CORT) levels and PAC1R knock-down in CeA further reduce them. Finally, the CeA PAC1R knock-down blocks the increase in corticotropin-releasing factor (CRF) immunoreactivity induced by CSDS in CeA. Our findings support the notion that the persistent activation of the PACAP-PAC1R system in the CeA mediates the behavioral outcomes of chronic psychosocial stress independently of the hypothalamic-pituitary-adrenal axis, perhaps via the recruitment of the CRF system.
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Salguero A, Marengo L, Portillo-Salido E, Ruiz-Leyva L, Cendán CM, Morón I, Marcos Pautassi R. Administration of the sigma-1 receptor agonist PRE-084 at emerging adulthood, but not at early adolescence, attenuated ethanol-induced conditioned taste aversion in female rats. Neurosci Lett 2022; 778:136585. [PMID: 35318075 DOI: 10.1016/j.neulet.2022.136585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Revised: 03/07/2022] [Accepted: 03/18/2022] [Indexed: 11/17/2022]
Abstract
Ethanol-induced conditioned taste aversion (CTA) is greater in late adolescence or young adulthood than in early adolescence. The role of the sigma receptor system in this age-related difference has not been extensively explored, particularly in female rats. This study assessed the effects of the activation of sigma-1 receptors (S1-R), via the selective S1-R agonist PRE-084, on ethanol-induced CTA at early or at terminal adolescence/emerging adulthood (28 or 56 days-old at the beginning of the procedures, respectively) in female Wistar rats. The modulation of binge-like ethanol intake by PRE-084 was assessed at terminal adolescence. S1-R activation at the acquisition of ethanol-induced CTA attenuated such learning at terminal but not at early adolescence. PRE-084 did not significantly affect ethanol binge drinking in the terminal adolescents. These results highlight the role of S1-R in ethanol-induced CTA and suggest that differential functionality of this transmitter system may underlie age-specific sensitivities to the aversive effects of ethanol.
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Affiliation(s)
- Agustín Salguero
- Instituto de Investigación Médica M. y M. Ferreyra (INIMEC-CONICET-Universidad Nacional de Córdoba), Córdoba C.P. 5000, Argentina
| | - Leonardo Marengo
- Instituto de Investigación Médica M. y M. Ferreyra (INIMEC-CONICET-Universidad Nacional de Córdoba), Córdoba C.P. 5000, Argentina
| | | | - Leandro Ruiz-Leyva
- Department of Pharmacology, Institute of Neuroscience, Biomedical Research Center (CIBM) Faculty of Medicine, University of Granada and Biosanitary Research Institute ibs.GRANADA, Granada, Spain
| | - Cruz Miguel Cendán
- Department of Pharmacology, Institute of Neuroscience, Biomedical Research Center (CIBM) Faculty of Medicine, University of Granada and Biosanitary Research Institute ibs.GRANADA, Granada, Spain
| | - Ignacio Morón
- Department of Psychobiology and Centre of Investigation of Mind, Brain, and Behaviour (CIMCYC), University of Granada, Spain.
| | - Ricardo Marcos Pautassi
- Instituto de Investigación Médica M. y M. Ferreyra (INIMEC-CONICET-Universidad Nacional de Córdoba), Córdoba C.P. 5000, Argentina; Facultad de Psicología, Universidad Nacional de Córdoba, Córdoba, C.P. 5000, Argentina.
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5
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Pituitary adenylate cyclase-activating polypeptide type 1 receptor within the nucleus accumbens core mediates excessive alcohol drinking in alcohol-preferring rats. Neuropharmacology 2022; 212:109063. [PMID: 35460713 DOI: 10.1016/j.neuropharm.2022.109063] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 03/19/2022] [Accepted: 04/12/2022] [Indexed: 12/15/2022]
Abstract
Alcohol use disorders (AUD) have a strong component of heritability; however, the neurobiological mechanisms mediating the propensity to consume excessive amounts of alcohol are still not well understood. Pituitary adenylate cyclase-activating polypeptide (PACAP), a highly conserved neuropeptide which exerts its effects mainly through the PAC1 receptor (PAC1R), has been suggested to be one of the mediators of the effects of drugs of abuse and alcohol. Here, we investigated the role of the PACAP/PAC1R system in excessive alcohol drinking in alcohol-preferring rats, an established animal model of AUD. Intracerebroventricular (i.c.v.) administration of the PAC1R antagonist PACAP(6-38) blocked excessive alcohol drinking and motivation to drink in Sardinian alcohol-preferring (Scr:sP) rats, without affecting water, saccharin, or sucrose intake. Notably, PACAP(6-38) did not affect ethanol responding in outbred Wistar rats. PACAP(6-38) also significantly reduced alcohol-seeking behavior under a second-order schedule of reinforcement. Using immunohistochemistry, a significant increase in the number of PAC1R positive cells was observed selectively in the nucleus accumbens (NAcc) Core of Scr:sP rats, compared to Wistar rats following alcohol drinking. Finally, excessive drinking in Scr:sP rats was suppressed by intra-NAcc Core, but not intra-NAcc Shell, PACAP(6-38), as well as by virally-mediated PAC1R knockdown in the NAcc Core. The present study shows that hyperactivity of the PACAP/PAC1R system specifically in the NAcc Core mediates excessive drinking of alcohol-preferring rats, and indicates that this system may represent a novel target for the treatment of AUD.
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Minnig MA, Park T, Echeveste Sanchez M, Cottone P, Sabino V. Viral-Mediated Knockdown of Nucleus Accumbens Shell PAC1 Receptor Promotes Excessive Alcohol Drinking in Alcohol-Preferring Rats. Front Behav Neurosci 2021; 15:787362. [PMID: 34924973 PMCID: PMC8678417 DOI: 10.3389/fnbeh.2021.787362] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 11/08/2021] [Indexed: 01/04/2023] Open
Abstract
Alcohol use disorder (AUD) is a chronic, relapsing disorder whose genetic and environmental susceptibility components are not fully understood. Neuropeptidergic signaling has been repeatedly implicated in modulating excessive alcohol drinking, especially within sub-regions of the striatum. Here, we investigated the potential involvement of the selective receptor for pituitary adenylate cyclase-activating polypeptide (PACAP), PAC1R, in the nucleus accumbens shell (NAcc Shell) in excessive alcohol drinking in alcohol-preferring rats, an established animal model of the genetic propensity for alcoholism. Scr:sP alcohol-preferring rats were trained to operantly self-administer alcohol and then either an AAV virus short-hairpin RNA (shRNA) targeted to knockdown PAC1R, or an AAV control virus were microinfused into the NAcc Shell. NAcc Shell PAC1R shRNA knockdown virus was confirmed to significantly decrease PAC1R levels in the NAcc Shell. The effects of NAcc Shell PAC1R shRNA knockdown on ethanol self-administration were investigated using a Fixed Ratio (FR) 1 and a Progressive Ratio (PR) schedule of reinforcement. The effect of PAC1R knockdown on self-administration of an alternative reinforcer, saccharin, was also assessed. The results showed that the reduction in PAC1R in the NAcc Shell led to excessive ethanol drinking, increased preference for ethanol, and higher motivation to drink. NAcc Shell PAC1R shRNA knockdown did not comparably increase saccharin self-administration, suggesting selectivity of action. These data suggest that NAcc Shell PAC1R may serves as a "brake" on alcohol drinking, and thereby the loss of function of PAC1R leads to excessive alcohol consumption. Therefore, the PACAP/PAC1R system may represent a novel target for the treatment of AUD.
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Affiliation(s)
| | | | | | | | - Valentina Sabino
- Laboratory of Addictive Disorders, Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, United States
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Valentina S, Blasio A, Ferragud A, Quadir SG, Iyer MR, Rice KC, Cottone P. Characterization of a differential reinforcement of low rates of responding task in non-deprived male and female rats: Role of Sigma-1 receptors. Neuropharmacology 2021; 200:108786. [PMID: 34516984 PMCID: PMC9869339 DOI: 10.1016/j.neuropharm.2021.108786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 08/25/2021] [Accepted: 09/06/2021] [Indexed: 01/26/2023]
Abstract
Impulsive action can be defined as the inability to withhold a response and represents one of the dimensions of the broad construct impulsivity. Here, we characterized a modified differential reinforcement of low rates of responding (DRL) task developed in our laboratory, in which impulsive action is measured in ad libitum fed/watered subjects. Specifically, we first determined the effects of both sex and estrous cycle on impulsive action by systematically comparing male and estrous-synchronized female subjects. In addition, we evaluated the convergent validity of this modified DRL task by testing the effects of the D2R/5HT2AR antagonist, aripiprazole, and the noncompetitive NMDAR antagonist, MK-801. Finally, we tested the effects of the selective antagonist BD-1063 and agonist PRE-084 of Sigma-1 receptor (Sig-1R) on impulsive action using this modified DRL task. We found that female rats showed and increased inability to withhold a response when compared to males, and this effect was driven by the metestrus/diestrus phase of the estrous cycle. In addition, aripiprazole and MK-801 fully retained their capability to reduce and increase impulsive action, respectively. Finally, the selective Sig-1R antagonist, BD-1063 dose-dependently reduced the inability to withhold a response in both sexes, though more potently in female rats. In summary, we show that impulsive action, as measured in a modified DRL task which minimizes energy-homeostatic influences, is a function of both sex and estrous cycle. Furthermore, we validate the convergent validity of the task and provide evidence that Sig-1R antagonism may represent a novel pharmacological strategy to reduce impulsive action.
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Affiliation(s)
- Sabino Valentina
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, Boston, MA, USA.
| | - Angelo Blasio
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, Boston, MA, USA
| | - Antonio Ferragud
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, Boston, MA, USA
| | - Sema G Quadir
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, Boston, MA, USA
| | - Malliga R Iyer
- Section on Medicinal Chemistry, National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD, USA
| | - Kenner C Rice
- Drug Design and Synthesis, National Institute on Drug Abuse and National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD, USA
| | - Pietro Cottone
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, Boston, MA, USA.
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Quadir SG, Tanino SM, Sami YN, Minnig MA, Iyer MR, Rice KC, Cottone P, Sabino V. Antagonism of Sigma-1 receptor blocks heavy alcohol drinking and associated hyperalgesia in male mice. Alcohol Clin Exp Res 2021; 45:1398-1407. [PMID: 34060104 PMCID: PMC8295198 DOI: 10.1111/acer.14635] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 04/16/2021] [Accepted: 05/10/2021] [Indexed: 11/26/2022]
Abstract
BACKGROUND Alcohol use disorder (AUD) is a complex psychiatric disease characterized by high alcohol intake as well as hyperkatifeia and hyperalgesia during withdrawal. A role for Sigma-1 receptors (Sig-1Rs) in the rewarding and reinforcing effects of alcohol has started to emerge in recent years, as rat studies have indicated that Sig-1R hyperactivity may result in excessive alcohol drinking. Sig-1R studies in mice are very scarce, and its potential role in alcohol-induced hyperalgesia is also unknown. METHODS In this study, we investigated the role of Sig-1R in alcohol drinking and associated hyperalgesia in male mice, using an intermittent access 2-bottle choice model of heavy drinking. RESULTS The Sig-1R antagonist BD-1063 was found dose dependently to reduce both alcohol intake and preference, without affecting either water or sucrose intake, suggesting that the effects are specific for alcohol. Notably, the ability of BD-1063 to suppress ethanol intake correlated with the individual baseline levels of alcohol drinking, suggesting that the treatment was more efficacious in heavy drinking animals. In addition, BD-1063 reversed alcohol-induced hyperalgesia during withdrawal, assessed using an automatic Hargreaves test, without affecting thermal sensitivity in alcohol-naïve animals or locomotor activity in either group. CONCLUSIONS These data show that Sig-1R antagonism dose-dependently reduced ethanol consumption in heavy drinking mice as well as its efficacy in reducing alcohol-induced hyperalgesia. These findings provide a foundation for the development of novel treatments for AUD and associated pain states.
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Affiliation(s)
- Sema G. Quadir
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, 72 E. Concord St., Boston, MA, USA
| | - Sean M. Tanino
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, 72 E. Concord St., Boston, MA, USA
| | - Yasmine N. Sami
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, 72 E. Concord St., Boston, MA, USA
| | - Margaret A. Minnig
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, 72 E. Concord St., Boston, MA, USA
| | - Malliga R. Iyer
- Section on Medicinal Chemistry, National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD, USA
| | - Kenner C. Rice
- Drug Design and Synthesis, National Institute on Drug Abuse and National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD, USA
| | - Pietro Cottone
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, 72 E. Concord St., Boston, MA, USA
| | - Valentina Sabino
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, 72 E. Concord St., Boston, MA, USA
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Pituitary adenylate cyclase-activating polypeptide (PACAP) modulates dependence-induced alcohol drinking and anxiety-like behavior in male rats. Neuropsychopharmacology 2021; 46:509-518. [PMID: 33191400 PMCID: PMC8027820 DOI: 10.1038/s41386-020-00904-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 10/23/2020] [Indexed: 02/07/2023]
Abstract
Alcohol use disorder (AUD) is a devastating illness defined by periods of heavy drinking and withdrawal, often leading to a chronic relapsing course. Initially, alcohol is consumed for its positive reinforcing effects, but later stages of AUD are characterized by drinking to alleviate withdrawal-induced negative emotional states. Brain stress response systems in the extended amygdala are recruited by excessive alcohol intake, sensitized by repeated withdrawal, and contribute to the development of addiction. In this study, we investigated one such brain stress response system, pituitary adenylate cyclase-activating polypeptide (PACAP), and its cognate receptor, PAC1R, in alcohol withdrawal-induced behaviors. During acute withdrawal, rats exposed to chronic intermittent ethanol vapor (ethanol-dependent) displayed a significant increase in PACAP levels in the bed nucleus of the stria terminalis (BNST), a brain area within the extended amygdala critically involved in both stress and withdrawal. No changes in PACAP levels were observed in the central nucleus of the amygdala. Site-specific microinfusion of the PAC1R antagonist PACAP(6-38) into the BNST dose-dependently blocked excessive alcohol intake in ethanol-dependent rats without affecting water intake overall or basal ethanol intake in control, nondependent rats. Intra-BNST PACAP(6-38) also reversed ethanol withdrawal-induced anxiety-like behavior in ethanol-dependent rats, but did not affect this measure in control rats. Our findings show that chronic intermittent exposure to ethanol recruits the PACAP/PAC1R system of the BNST and that these neuroadaptations mediate the heightened alcohol drinking and anxiety-like behavior observed during withdrawal, suggesting that this system represents a major brain stress element responsible for the negative reinforcement associated with the "dark side" of alcohol addiction.
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Szczepańska K, Kuder KJ, Kieć-Kononowicz K. Dual-targeting Approach on Histamine H 3 and Sigma-1 Receptor Ligands as Promising Pharmacological Tools in the Treatment of CNS-linked Disorders. Curr Med Chem 2021; 28:2974-2995. [PMID: 32767910 DOI: 10.2174/0929867327666200806103144] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 07/16/2020] [Accepted: 07/16/2020] [Indexed: 11/22/2022]
Abstract
With the recent market approval of Pitolisant (Wakix®), the interest in clinical application for novel multifunctional histamine H3 receptor antagonists has clearly increased. Several combinations of different H3R pharmacophores with pharmacophoric elements of other G-protein coupled receptors, transporters, or enzymes have been synthesized by numerous pharmaceutical companies and academic institutions. Since central nervous system disorders are characterized by diverse physiological dysfunctions and deregulations of a complex network of signaling pathways, optimal multipotent drugs should simultaneously and peculiarly modulate selected groups of biological targets. Interestingly, very recent studies have shown that some clinically evaluated histamine H3 receptor antagonists possess a nanomolar affinity for sigma-1 receptor binding sites, suggesting that this property might play a role in their overall efficacy. The sigma-1 receptor, unusual and yet obscure protein, is supposed to be involved in numerous CNS pathologies through neuroprotection and neuroplasticity. These two different biological structures, histamine H3 and sigma-1 receptors, combined, can represent a potential fruitful target for therapeutic developments in tackling numerous human diseases.
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Affiliation(s)
- Katarzyna Szczepańska
- Department of Technology and Biotechnology of Drugs, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, Krakow 30-688, Poland
| | - Kamil J Kuder
- Department of Technology and Biotechnology of Drugs, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, Krakow 30-688, Poland
| | - Katarzyna Kieć-Kononowicz
- Department of Technology and Biotechnology of Drugs, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, Krakow 30-688, Poland
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Quadir SG, Tanino SM, Rohl CD, Sahn JJ, Yao EJ, Cruz LDR, Cottone P, Martin SF, Sabino V. The Sigma-2 receptor / transmembrane protein 97 (σ2R/TMEM97) modulator JVW-1034 reduces heavy alcohol drinking and associated pain states in male mice. Neuropharmacology 2020; 184:108409. [PMID: 33221481 DOI: 10.1016/j.neuropharm.2020.108409] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 10/27/2020] [Accepted: 11/17/2020] [Indexed: 12/15/2022]
Abstract
Alcohol Use Disorder (AUD) is a chronic relapsing disorder characterized by compulsive alcohol intake, loss of control over alcohol intake, and a negative emotional state when access to alcohol is prevented. AUD is also closely tied to pain, as repeated alcohol drinking leads to increased pain sensitivity during withdrawal. The sigma-2 receptor, recently identified as transmembrane protein 97 (σ2R/TMEM97), is an integral membrane protein involved in cholesterol homeostasis and lipid metabolism. Selective σ2R/Tmem97 modulators have been recently shown to relieve mechanical hypersensitivity in animal models of neuropathic pain as well as to attenuate alcohol withdrawal signs in C. elegans and to reduce alcohol drinking in rats, suggesting a potential key role for this protein in alcohol-related behaviors. In this study, we tested the effects of a potent and selective σ2R/TMEM97 ligand, JVW-1034, on heavy alcohol drinking and alcohol-induced heightened pain states in mice using an intermittent access model. Administration of JVW-1034 decreased both ethanol intake and preference for ethanol, without affecting water intake, total fluid intake, or food intake. Notably, this effect was specific for alcohol, as JVW-1034 had no effect on sucrose intake. Furthermore, JVW-1034 reduced both thermal hyperalgesia and mechanical hypersensitivity in ethanol withdrawn mice. Our data provide important evidence that modulation of σ2R/TMEM97 with small molecules can mediate heavy alcohol drinking as well as chronic alcohol-induced heightened pain sensitivity, thereby identifying a promising novel pharmacological target for AUD and associated pain states.
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Affiliation(s)
- Sema G Quadir
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, 72 E. Concord St, Boston, MA, USA
| | - Sean M Tanino
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, 72 E. Concord St, Boston, MA, USA
| | - Christian D Rohl
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, 72 E. Concord St, Boston, MA, USA
| | - James J Sahn
- Department of Chemistry and Waggoner Center for Alcohol and Addiction Research, University of Texas at Austin, Austin, TX, USA
| | - Emily J Yao
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, 72 E. Concord St, Boston, MA, USA
| | - Luíza Dos Reis Cruz
- Department of Chemistry and Waggoner Center for Alcohol and Addiction Research, University of Texas at Austin, Austin, TX, USA
| | - Pietro Cottone
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, 72 E. Concord St, Boston, MA, USA
| | - Stephen F Martin
- Department of Chemistry and Waggoner Center for Alcohol and Addiction Research, University of Texas at Austin, Austin, TX, USA.
| | - Valentina Sabino
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, 72 E. Concord St, Boston, MA, USA.
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12
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Ruiz-Leyva L, Salguero A, Morón I, Portillo-Salido E, Cendán CM, Pautassi RM. Sigma-1 antagonism inhibits binge ethanol drinking at adolescence. Drug Alcohol Depend 2020; 215:108214. [PMID: 32791285 DOI: 10.1016/j.drugalcdep.2020.108214] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 07/14/2020] [Accepted: 07/23/2020] [Indexed: 12/26/2022]
Abstract
BACKGROUND Ethanol use during adolescence is a significant health problem, yet the pharmacological treatments to reduce adolescent binge drinking are scarce. The present study assessed, in male and female adolescent Wistar rats, if the sigma-1 receptor (S1-R) antagonists S1RA or BD-1063 disrupted ethanol drinking. METHODS Three times a week, for two weeks, the rats received the S1-R antagonists. Thirty min later they were exposed, for 2 h, to a bottle of 8% or 10 % v/v ethanol. A 24 h, two-bottle, ethanol intake test was conducted after termination of these procedures. A subset of these rats was tested for recognition memory via the novel object recognition test. RESULTS The rats given 64 mg/kg S1RA drank, in each binge session, significantly less than vehicle counterparts. Male rats given 4 or 16 mg/kg S1RA drank significantly less than those given 0 mg/kg in session 3 or in session 1 and 2, respectively; whereas female rats given 4 or 16 mg/kg drank significantly less than females given 0 mg/kg in session 2-5 or in sessions 2-6, respectively. Administration of 32 mg/kg, but not of 2 or 8 mg/kg, BD-1063 suppressed, across sessions, ethanol drinking. S1-R antagonism reduced absolute ethanol drinking at the two-bottle choice post-test. Recognition memory was not affected by the ethanol exposure. CONCLUSIONS The results indicate that S1-R antagonists may be promising targets to prevent increases in ethanol intake at adolescence. The persistent effect of S1-R antagonism in free-choice drinking suggests that modulation of the S1-R is altering plastic effects associated with ethanol exposure.
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Affiliation(s)
- Leandro Ruiz-Leyva
- Department of Pharmacology, Faculty of Medicine, University of Granada, Spain; Institute of Neuroscience, Biomedical Research Center (CIBM), University of Granada, Spain; Instituto de Investigación Biosanitaria (IBS), Granada, Spain
| | - Agustín Salguero
- Instituto de Investigación Médica M. y M. Ferreyra (INIMEC-CONICET-Universidad Nacional de Córdoba), Córdoba, C.P. 5000, Argentina; Facultad de Psicología, Universidad Nacional de Córdoba, Córdoba, C.P. 5000, Argentina
| | - Ignacio Morón
- Department of Psychobiology and Centre of Investigation of Mind, Brain, and Behaviour (CIMCYC), University of Granada, Spain
| | - Enrique Portillo-Salido
- Drug Discovery and Preclinical Development, Esteve Pharmaceuticals, Parc Científic de Barcelona, Barcelona, Spain
| | - Cruz Miguel Cendán
- Department of Pharmacology, Faculty of Medicine, University of Granada, Spain; Institute of Neuroscience, Biomedical Research Center (CIBM), University of Granada, Spain; Instituto de Investigación Biosanitaria (IBS), Granada, Spain.
| | - Ricardo Marcos Pautassi
- Instituto de Investigación Médica M. y M. Ferreyra (INIMEC-CONICET-Universidad Nacional de Córdoba), Córdoba, C.P. 5000, Argentina; Facultad de Psicología, Universidad Nacional de Córdoba, Córdoba, C.P. 5000, Argentina.
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13
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Hicks C, Sabino V, Cottone P. The Alpha-1 Adrenergic Receptor Antagonist Prazosin Reduces Binge-Like Eating in Rats. Nutrients 2020; 12:nu12061569. [PMID: 32481494 PMCID: PMC7352795 DOI: 10.3390/nu12061569] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 05/18/2020] [Accepted: 05/26/2020] [Indexed: 01/19/2023] Open
Abstract
Background: Binge-eating disorder is a pervasive addiction-like disorder that is defined by excessive and uncontrollable consumption of food within brief periods of time. The aim of the current study was to examine the role of the brain noradrenergic system in binge-like eating through the use of the alpha-1 adrenergic receptor antagonist prazosin. Methods: For this purpose, we employed a limited access model whereby male Wistar rats were allowed to nosepoke for either chow (Chow rats) or a sugary, highly palatable food (Palatable rats) for 1 h/day. The effects of prazosin (0, 0.5, 1 and 2 mg/kg, i.p.) were tested in a fixed ratio 1 (FR1) and progressive ratio (PR) schedule of reinforcement. Results: The results show that prazosin preferentially reduced the responses for palatable food in a FR1 reinforcement schedule; when tested in a PR schedule of reinforcement, prazosin increased breakpoint in both Chow and Palatable rats, but more potently and more efficaciously in the latter. Our results suggest that prazosin treatment preferentially increased the motivational properties of the palatable diet. Conclusions: The current findings provide the characterization of the effects of prazosin on binge-like eating and offer support to the existing literature showing the important role of the noradrenergic system in addiction-like behavior.
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14
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Sigma receptor-induced heavy drinking in rats: Modulation by the opioid receptor system. Pharmacol Biochem Behav 2020; 192:172914. [PMID: 32205151 DOI: 10.1016/j.pbb.2020.172914] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 03/18/2020] [Accepted: 03/19/2020] [Indexed: 02/04/2023]
Abstract
Alcohol use disorder (AUD) is a major cause of morbidity and mortality worldwide, for which new efficacious treatments are necessary. The opioid receptor system is a mediator of the rewarding effects of alcohol; in particular, while activation of μ opioid receptors enhances ethanol intake in rodents, opioid-receptor antagonists, such as naloxone and naltrexone, reduce its pleasurable and reinforcing effects, thereby decreasing alcohol. Sigma receptors (Sig-Rs) have been proposed as modulators of the effects of alcohol and, therefore, as a potential new pharmacological target for AUD. Somewhat analogously to μ opioid ligands, SigR agonists increase, while SigR antagonists decrease alcohol intake in animal models of excessive alcohol drinking. However, a potential cross-talk between these two receptor systems in relation to alcohol consumption has so far not been investigated. Here, we addressed this question pharmacologically, by testing the effects of either activating or inhibiting opioid receptors on the heavy alcohol drinking induced by chronic stimulation of SigR in alcohol-preferring rats. We found that the opioid receptor agonist morphine, which per se increases ethanol intake, at a sub-threshold dose reduces the binge-like drinking induced by the repeated treatment with the SigR agonist 1,3-di-o-tolylguanidine (DTG); conversely, the opioid receptor antagonist naltrexone, which per se reduces ethanol intake, at a sub-threshold dose potentiates the DTG-induced binge-like drinking. Our data show a cross-talk between the opioid and SigR systems relevant to the modulation of alcohol drinking, which provides important insights into the neurobiology of AUD and may lead to the development of novel therapies, either standalone or in combination.
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15
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Tapia MA, Lever JR, Lever SZ, Will MJ, Park ES, Miller DK. Sigma-1 receptor ligand PD144418 and sigma-2 receptor ligand YUN-252 attenuate the stimulant effects of methamphetamine in mice. Psychopharmacology (Berl) 2019; 236:3147-3158. [PMID: 31139878 DOI: 10.1007/s00213-019-05268-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 05/01/2019] [Indexed: 12/12/2022]
Abstract
RATIONALE Previous research indicates that the selective sigma-1 receptor ligand PD144418 and the selective sigma-2 ligands YUN-252 can inhibit cocaine-induced hyperactivity. The effects of these ligands on other stimulants, such as methamphetamine, have not been reported. OBJECTIVES The present study examined the effects of PD144418 and YUN-252 pretreatment on methamphetamine-induced hyperactivity after acute treatment. METHODS Mice (n = 8-14/group) were injected with PD144418 (3.16, 10, or 31.6 μmol/kg), YUN-252 (0.316, 3.16, 31.6 μmol/kg), or saline. After 15 min, mice injected with 2.69 μmol/kg methamphetamine or saline vehicle, where distance traveled during a 60-min period was recorded. Additionally, the effect of PD144418 on the initiation and expression of methamphetamine sensitization was determined by treating mice (n = 8-14/group) with PD144418, methamphetamine or saline repeatedly over a 5-day period, and testing said mice with a challenge dose after a 7-day withdrawal period. RESULTS Results indicate that both PD144418 and YUN-252, in a dose-dependent manner, attenuated hyperactivity induced by an acute methamphetamine injection. Specifically, 10 μmol/kg or 31.6 μmol/kg of PD144418 and 31 μmol/kg of YUN-252 suppressed methamphetamine-induced hyperactivity. In regard to methamphetamine sensitization, while 10 μmol/kg PD144418 prevented the initiation of methamphetamine sensitization, it did not have an effect on the expression. CONCLUSIONS Overall, the current results suggest an intriguing potential for this novel sigma receptor ligand as a treatment for the addictive properties of methamphetamine. Future analysis of this novel sigma receptor ligand in assays directly measuring reinforcement properties will be critical.
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Affiliation(s)
- Melissa A Tapia
- Department of Psychological Sciences, University of Missouri, 210 McAlester Hall, Columbia, MO, 65211, USA.
| | - John R Lever
- Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, and Department of Radiology and Radiopharmaceutical Sciences Institute, University of Missouri, Columbia, MO, 65211, USA
| | - Susan Z Lever
- Department of Chemistry and MU Research Reactor Center, University of Missouri, Columbia, MO, 65211, USA
| | - Matthew J Will
- Department of Psychological Sciences, University of Missouri, 210 McAlester Hall, Columbia, MO, 65211, USA
| | - Eric S Park
- Department of Psychological Sciences, University of Missouri, 210 McAlester Hall, Columbia, MO, 65211, USA
| | - Dennis K Miller
- Department of Psychological Sciences, University of Missouri, 210 McAlester Hall, Columbia, MO, 65211, USA
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16
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Quadir SG, Cottone P, Sabino V. Role of Sigma Receptors in Alcohol Addiction. Front Pharmacol 2019; 10:687. [PMID: 31258483 PMCID: PMC6586921 DOI: 10.3389/fphar.2019.00687] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 05/27/2019] [Indexed: 12/13/2022] Open
Abstract
Pharmacological treatments for alcohol use disorder (AUD) are few in number and often ineffective, despite the significant research carried out so far to better comprehend the neurochemical underpinnings of the disease. Hence, research has been directed towards the discovery of novel therapeutic targets for the treatment of AUD. In the last decade, the sigma receptor system has been proposed as a potential mediator of alcohol reward and reinforcement. Preclinical studies have shown that the motivational effects of alcohol and excessive ethanol consumption involve the recruitment of the sigma receptor system. Furthermore, sigma receptor antagonism has been shown to be sufficient to inhibit many behaviors related to AUDs. This paper will review the most current evidence in support of this receptor system as a potential target for the development of pharmacological agents for the treatment of alcohol addiction.
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Affiliation(s)
- Sema G Quadir
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, Boston, MA, United States
| | - Pietro Cottone
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, Boston, MA, United States
| | - Valentina Sabino
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, Boston, MA, United States
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17
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Tapia MA, Lee JR, Gereau GB, Moore JM, Weise VN, Mason KL, Cessac ME, Bodeen JL, Miller DK, Will MJ. Sigma-1 receptor antagonist PD144418 suppresses food reinforced operant responding in rats. Behav Brain Res 2019; 362:71-76. [PMID: 30639509 DOI: 10.1016/j.bbr.2019.01.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 01/08/2019] [Accepted: 01/08/2019] [Indexed: 01/20/2023]
Abstract
Sigma-1 (σ1) receptors have been investigated for their involvement in learning, rewarding and motivational processes, particularly as it relates to substances of abuse. Few studies have examined the effects of σ1 receptor agonists and antagonists on the rewarding and motivational properties of natural reinforcers, such as food. Studies that have investigated σ1 receptor agonists and antagonists has produced conflicting results. σ1 receptor antagonist PD144418 has been found to produce a dose-dependent attenuation of locomotor activity induced by cocaine, and by itself, does not suppress basal locomotor activity in mice. However, its effects on reward and motivation as it relates to food are unknown. The present study examined the involvement of σ1 receptors in mediating the rewarding and motivational properties of food using an operant task. The results indicated that at the highest dose (10 μmol/kg), PD144418 significantly attenuated the number of active lever responses for chow pellets but did not decrease the number of active lever responses for sucrose pellets under a fixed ratio (FR2) schedule of reinforcement. However, under a progressive ratio (PR) reinforcement schedule, 10 μmol/kg of PD14418 significantly reduced the breakpoint, a measure indicative of effort or motivation, for both chow and sucrose pellets. When ad libitum chow or sucrose pellets were made freely available (i.e. no lever press required) inside the operant chamber, 10 μmol/kg, PD144418 did not have an effect on number of pellets consumed. These findings indicate that PD144418 reduces the motivational effort of a food reinforced behavior.
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Affiliation(s)
- Melissa A Tapia
- Department of Psychological Sciences, University of Missouri, Columbia, MO 65211, USA.
| | - Jenna R Lee
- Interdisciplinary Neuroscience Program, University of Missouri, Columbia, MO 65211, USA
| | - Graydon B Gereau
- Department of Biological Sciences, University of Missouri, Columbia, MO 65211, USA
| | - Justin M Moore
- Department of Psychological Sciences, University of Missouri, Columbia, MO 65211, USA
| | - Valerie N Weise
- Department of Psychological Sciences, University of Missouri, Columbia, MO 65211, USA
| | - Kelsey L Mason
- Department of Psychological Sciences, University of Missouri, Columbia, MO 65211, USA; Department of Biological Sciences, University of Missouri, Columbia, MO 65211, USA
| | - Mikala E Cessac
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO 65211, USA
| | - Jeffrey L Bodeen
- Department of Psychological Sciences, University of Missouri, Columbia, MO 65211, USA; Department of Biological Sciences, University of Missouri, Columbia, MO 65211, USA
| | - Dennis K Miller
- Department of Psychological Sciences, University of Missouri, Columbia, MO 65211, USA
| | - Matthew J Will
- Department of Psychological Sciences, University of Missouri, Columbia, MO 65211, USA
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18
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Moore CF, Panciera JI, Sabino V, Cottone P. Neuropharmacology of compulsive eating. Philos Trans R Soc Lond B Biol Sci 2019; 373:rstb.2017.0024. [PMID: 29352024 DOI: 10.1098/rstb.2017.0024] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/04/2017] [Indexed: 12/22/2022] Open
Abstract
Compulsive eating behaviour is a transdiagnostic construct observed in certain forms of obesity and eating disorders, as well as in the proposed construct of 'food addiction'. Compulsive eating can be conceptualized as comprising three elements: (i) habitual overeating, (ii) overeating to relieve a negative emotional state, and (iii) overeating despite adverse consequences. Neurobiological processes that include maladaptive habit formation, the emergence of a negative affect, and dysfunctions in inhibitory control are thought to drive the development and persistence of compulsive eating behaviour. These complex psychobehavioural processes are under the control of various neuropharmacological systems. Here, we describe the current evidence implicating these systems in compulsive eating behaviour, and contextualize them within the three elements. A better understanding of the neuropharmacological substrates of compulsive eating behaviour has the potential to significantly advance the pharmacotherapy for feeding-related pathologies.This article is part of a discussion meeting issue 'Of mice and mental health: facilitating dialogue between basic and clinical neuroscientists'.
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Affiliation(s)
- Catherine F Moore
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, 72 E. Concord Street, R-618, Boston, MA 02118, USA.,Graduate Program for Neuroscience, Boston University School of Medicine, 72 E. Concord Street, R-618, Boston, MA 02118, USA
| | - Julia I Panciera
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, 72 E. Concord Street, R-618, Boston, MA 02118, USA.,MS in Medical Sciences Program, Graduate Medical Sciences, Boston University School of Medicine, 72 E. Concord Street, R-618, Boston, MA 02118, USA.,Master of Public Health Program, Department of Health Policy and Management, Boston University School of Public Health, 715 Albany Street, Boston, MA, USA
| | - Valentina Sabino
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, 72 E. Concord Street, R-618, Boston, MA 02118, USA
| | - Pietro Cottone
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, 72 E. Concord Street, R-618, Boston, MA 02118, USA
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19
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Small molecule modulators of σ2R/Tmem97 reduce alcohol withdrawal-induced behaviors. Neuropsychopharmacology 2018; 43:1867-1875. [PMID: 29728649 PMCID: PMC6046036 DOI: 10.1038/s41386-018-0067-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 03/09/2018] [Accepted: 04/05/2018] [Indexed: 12/29/2022]
Abstract
Repeated cycles of intoxication and withdrawal enhance the negative reinforcing properties of alcohol and lead to neuroadaptations that underlie withdrawal symptoms driving alcohol dependence. Pharmacotherapies that target these neuroadaptations may help break the cycle of dependence. The sigma-1 receptor (σ1R) subtype has attracted interest as a possible modulator of the rewarding and reinforcing effects of alcohol. However, whether the sigma-2 receptor, recently cloned and identified as transmembrane protein 97 (σ2R/TMEM97), plays a role in alcohol-related behaviors is currently unknown. Using a Caenorhabditis elegans model, we identified two novel, selective σ2R/Tmem97 modulators that reduce alcohol withdrawal behavior via an ortholog of σ2R/TMEM97. We then show that one of these compounds blunted withdrawal-induced excessive alcohol drinking in a well-established rodent model of alcohol dependence. These discoveries provide the first evidence that σ2R/TMEM97 is involved in alcohol withdrawal behaviors and that this receptor is a potential new target for treating alcohol use disorder.
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20
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Optimisation of cognitive performance in rodent operant (touchscreen) testing: Evaluation and effects of reinforcer strength. Learn Behav 2018; 45:252-262. [PMID: 28205186 PMCID: PMC5565648 DOI: 10.3758/s13420-017-0260-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Operant testing is a widely used and highly effective method of studying cognition in rodents. Performance on such tasks is sensitive to reinforcer strength. It is therefore advantageous to select effective reinforcers to minimize training times and maximize experimental throughput. To quantitatively investigate the control of behavior by different reinforcers, performance of mice was tested with either strawberry milkshake or a known powerful reinforcer, super saccharin (1.5% or 2% (w/v) saccharin/1.5% (w/v) glucose/water mixture). Mice were tested on fixed (FR)- and progressive-ratio (PR) schedules in the touchscreen-operant testing system. Under an FR schedule, both the rate of responding and number of trials completed were higher in animals responding for strawberry milkshake versus super saccharin. Under a PR schedule, mice were willing to emit similar numbers of responses for strawberry milkshake and super saccharin; however, analysis of the rate of responding revealed a significantly higher rate of responding by animals reinforced with milkshake versus super saccharin. To determine the impact of reinforcer strength on cognitive performance, strawberry milkshake and super saccharin-reinforced animals were compared on a touchscreen visual discrimination task. Animals reinforced by strawberry milkshake were significantly faster to acquire the discrimination than animals reinforced by super saccharin. Taken together, these results suggest that strawberry milkshake is superior to super saccharin for operant behavioral testing and further confirms that the application of response rate analysis to multiple ratio tasks is a highly sensitive method for the detection of behavioral differences relevant to learning and motivation.
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21
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Logrip ML, Walker JR, Ayanwuyi LO, Sabino V, Ciccocioppo R, Koob GF, Zorrilla EP. Evaluation of Alcohol Preference and Drinking in msP Rats Bearing a Crhr1 Promoter Polymorphism. Front Psychiatry 2018; 9:28. [PMID: 29497387 PMCID: PMC5818434 DOI: 10.3389/fpsyt.2018.00028] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2017] [Accepted: 01/23/2018] [Indexed: 12/22/2022] Open
Abstract
Alcoholism is a pervasive societal problem, yet available pharmacotherapies fail to treat most sufferers. The type 1 corticotropin-releasing factor (CRF1) receptor has received much attention for its putative role in the progression to alcohol dependence, although at present its success in clinical trials has been limited. Two single-nucleotide polymorphisms in the rat Crhr1 promoter have been identified in the Marchigian substrain of Sardinian alcohol-preferring (msP) rats. Unlike other Wistar-derived alcohol-preferring lines, nondependent msP rats reduce their alcohol self-administration in response to CRF1 antagonists and show increased brain CRF1 expression. The current study tested the hypotheses that the A alleles in the Crhr1 promoter polymorphisms are: (1) unique to msP (vs. CRF1 antagonist-insensitive) alcohol-preferring lines and (2) associate with greater alcohol preference or intake. Two related polymorphisms were observed in which both loci on a given chromosome were either mutant variant (A) or wild-type (G) alleles within the distal Crhr1 promoter of 17/25 msP rats (68%), as compared to 0/23 Indiana P rats, 0/20 Sardinian alcohol-preferring rats bred at Scripps (Scr:sP) and 0/21 outbred Wistar rats. Alcohol consumption in msP rats did not differ according to the presence of Crhr1 A alleles, but greater alcohol preference (98%) was observed in A allele homozygous msP rats (AA) compared to msP rats with wild-type (GG, 91%) or heterozygous (GA, 91%) genotypes. The greater alcohol preference reflected decreased water intake, accompanied by reduced total calories consumed by AA rats. The data show that msP rats differentially possess mutant A variant alleles in the polymorphic promoter region of the Crhr1 gene that may differentially regulate consumption.
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Affiliation(s)
- Marian L Logrip
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, CA, United States.,Department of Psychology, Indiana University - Purdue University Indianapolis, Indianapolis, IN, United States
| | - John R Walker
- Genomics Institute of the Novartis Research Foundation, San Diego, CA, United States
| | - Lydia O Ayanwuyi
- Pharmacology Unit, School of Pharmacy, University of Camerino, Camerino, Italy
| | - Valentina Sabino
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, CA, United States.,Laboratory of Addictive Disorders, Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, United States
| | - Roberto Ciccocioppo
- Pharmacology Unit, School of Pharmacy, University of Camerino, Camerino, Italy
| | - George F Koob
- Neurobiology of Addiction Section, Integrative Neuroscience Research Branch, National Institute on Drug Abuse, Baltimore, MD, United States
| | - Eric P Zorrilla
- Department of Neuroscience, The Scripps Research Institute, La Jolla, CA, United States
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22
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Arena E, Dichiara M, Floresta G, Parenti C, Marrazzo A, Pittalà V, Amata E, Prezzavento O. Novel Sigma-1 receptor antagonists: from opioids to small molecules: what is new? Future Med Chem 2018; 10:231-256. [PMID: 29185346 DOI: 10.4155/fmc-2017-0164] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2023] Open
Abstract
Sigma-1 (σ1) receptor has been identified as a chaperone protein that interacts with other proteins, such as N-methyl-D-aspartate (NMDA) and opioid receptors, modulating their activity. σ1 receptor antagonists have been developed to obtain useful compounds for the treatment of psychoses, pain, drug abuse and cancer. Some interesting compounds such as E-5842 (5) and MS-377 (24), haloperidol and piperazine derivatives, respectively, were endowed with high affinity for σ1 receptors (Ki σ1 = 4 and 73 nM; Ki σ2 = 220 and 6900, respectively). They were developed for the treatment of psychotic disorders and 5 also underwent Phase II clinical trials suggesting interesting potential therapeutic applications. Here, σ1 receptor antagonists have been grouped based on chemical structure and reviewed according to structure-activity relationship and potential therapeutic role.
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Affiliation(s)
- Emanuela Arena
- Department of Drug Sciences, Medicinal Chemistry Section, University of Catania, Viale A Doria 6, 95125 Catania, Italy
| | - Maria Dichiara
- Department of Drug Sciences, Medicinal Chemistry Section, University of Catania, Viale A Doria 6, 95125 Catania, Italy
| | - Giuseppe Floresta
- Department of Drug Sciences, Medicinal Chemistry Section, University of Catania, Viale A Doria 6, 95125 Catania, Italy
- Department of Chemical Sciences, University of Catania, Viale A Doria 6, 95125 Catania, Italy
| | - Carmela Parenti
- Department of Drug Sciences, Pharmacology Section, University of Catania, Viale A Doria 6, 95125 Catania, Italy
| | - Agostino Marrazzo
- Department of Drug Sciences, Medicinal Chemistry Section, University of Catania, Viale A Doria 6, 95125 Catania, Italy
| | - Valeria Pittalà
- Department of Drug Sciences, Medicinal Chemistry Section, University of Catania, Viale A Doria 6, 95125 Catania, Italy
| | - Emanuele Amata
- Department of Drug Sciences, Medicinal Chemistry Section, University of Catania, Viale A Doria 6, 95125 Catania, Italy
| | - Orazio Prezzavento
- Department of Drug Sciences, Medicinal Chemistry Section, University of Catania, Viale A Doria 6, 95125 Catania, Italy
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23
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Moore CF, Schlain GS, Mancino S, Sabino V, Cottone P. A behavioral and pharmacological characterization of palatable diet alternation in mice. Pharmacol Biochem Behav 2017; 163:1-8. [PMID: 29097161 PMCID: PMC5911178 DOI: 10.1016/j.pbb.2017.10.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 10/09/2017] [Accepted: 10/29/2017] [Indexed: 12/28/2022]
Abstract
Obesity and eating disorders are widespread in Western societies. Both the increased availability of highly palatable foods and dieting are major risk factors contributing to the epidemic of disorders of feeding. The purpose of this study was to characterize an animal model of maladaptive feeding induced by intermittent access to a palatable diet alternation in mice. In this study, mice were either continuously provided with standard chow food (Chow/Chow), or provided with standard chow for 2days and a high-sucrose, palatable food for 1day (Chow/Palatable). Following stability of intake within the cycling paradigm, we then investigated the effects of several pharmacological treatments on excessive eating of palatable food: naltrexone, an opioid receptor antagonist, SR141716A, a cannabinoid-1 receptor antagonist/inverse agonist, and BD-1063, a sigma-1 receptor antagonist. Over successive cycles, Chow/Palatable mice showed an escalation of palatable food intake within the first hour of renewed access to palatable diet and displayed hypophagia upon its removal. Naltrexone, SR141716A, and BD-1063 all reduced overconsumption of palatable food during this first hour. Here we provide evidence of strong face and convergent validity in a palatable diet alternation model in mice, confirming multiple shared underlying mechanisms of pathological eating across species, and thus making it a useful therapeutic development tool.
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Affiliation(s)
- Catherine F Moore
- Laboratory of Addictive Disorders, Departments of Pharmacology and Experimental Therapeutics and Psychiatry, Boston University School of Medicine, Boston, MA, USA; Graduate Program for Neuroscience, Boston University School of Medicine, Boston, MA, USA
| | - Gabrielle S Schlain
- Laboratory of Addictive Disorders, Departments of Pharmacology and Experimental Therapeutics and Psychiatry, Boston University School of Medicine, Boston, MA, USA
| | - Samantha Mancino
- Laboratory of Addictive Disorders, Departments of Pharmacology and Experimental Therapeutics and Psychiatry, Boston University School of Medicine, Boston, MA, USA
| | - Valentina Sabino
- Laboratory of Addictive Disorders, Departments of Pharmacology and Experimental Therapeutics and Psychiatry, Boston University School of Medicine, Boston, MA, USA
| | - Pietro Cottone
- Laboratory of Addictive Disorders, Departments of Pharmacology and Experimental Therapeutics and Psychiatry, Boston University School of Medicine, Boston, MA, USA.
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Bell RL, Hauser SR, Liang T, Sari Y, Maldonado-Devincci A, Rodd ZA. Rat animal models for screening medications to treat alcohol use disorders. Neuropharmacology 2017; 122:201-243. [PMID: 28215999 PMCID: PMC5659204 DOI: 10.1016/j.neuropharm.2017.02.004] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2017] [Revised: 02/02/2017] [Accepted: 02/05/2017] [Indexed: 01/21/2023]
Abstract
The purpose of this review is to present animal research models that can be used to screen and/or repurpose medications for the treatment of alcohol abuse and dependence. The focus will be on rats and in particular selectively bred rats. Brief introductions discuss various aspects of the clinical picture, which provide characteristics of individuals with alcohol use disorders (AUDs) to model in animals. Following this, multiple selectively bred rat lines will be described and evaluated in the context of animal models used to screen medications to treat AUDs. Next, common behavioral tests for drug efficacy will be discussed particularly as they relate to stages in the addiction cycle. Tables highlighting studies that have tested the effects of compounds using the respective techniques are included. Wherever possible the Tables are organized chronologically in ascending order to describe changes in the focus of research on AUDs over time. In general, high ethanol-consuming selectively bred rats have been used to test a wide range of compounds. Older studies usually followed neurobiological findings in the selected lines that supported an association with a propensity for high ethanol intake. Most of these tests evaluated the compound's effects on the maintenance of ethanol drinking. Very few compounds have been tested during ethanol-seeking and/or relapse and fewer still have assessed their effects during the acquisition of AUDs. Overall, while a substantial number of neurotransmitter and neuromodulatory system targets have been assessed; the roles of sex- and age-of-animal, as well as the acquisition of AUDs, ethanol-seeking and relapse continue to be factors and behaviors needing further study. This article is part of the Special Issue entitled "Alcoholism".
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Affiliation(s)
- Richard L Bell
- Indiana University School of Medicine, Department of Psychiatry, Indianapolis, IN 46202, USA.
| | - Sheketha R Hauser
- Indiana University School of Medicine, Department of Psychiatry, Indianapolis, IN 46202, USA
| | - Tiebing Liang
- Indiana University School of Medicine, Department of Gastroenterology, Indianapolis, IN 46202, USA
| | - Youssef Sari
- University of Toledo, Department of Pharmacology, Toledo, OH 43614, USA
| | | | - Zachary A Rodd
- Indiana University School of Medicine, Department of Psychiatry, Indianapolis, IN 46202, USA
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Pathological Overeating: Emerging Evidence for a Compulsivity Construct. Neuropsychopharmacology 2017; 42:1375-1389. [PMID: 27922596 PMCID: PMC5436113 DOI: 10.1038/npp.2016.269] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 11/18/2016] [Accepted: 11/22/2016] [Indexed: 12/11/2022]
Abstract
Compulsive eating behavior is a transdiagnostic construct that is characteristic of medical and psychiatric conditions such as forms of obesity and eating disorders. Although feeding research is moving toward a better understanding of the proposed addictive properties of food, the components and the mechanisms contributing to compulsive eating are not yet clearly defined or understood. Current understanding highlights three elements of compulsive behavior as it applies to pathological overeating: (1) habitual overeating; (2) overeating to relieve a negative emotional state; and (3) overeating despite aversive consequences. These elements emerge through mechanisms involving pathological habit formation through an aberrant learning process, the emergence of a negative emotional state, and dysfunctions in behavioral control. Dysfunctions in systems within neurocircuitries that comprise the basal ganglia, the extended amygdala, and the prefrontal cortex result in compulsive eating behaviors. Here, we present evidence to relate compulsive eating behavior and addiction and to characterize their underlying neurobiological mechanisms. A major need to improve understanding of compulsive eating through the integration of complex motivational, emotional, and cognitive constructs is warranted.
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Lipids in psychiatric disorders and preventive medicine. Neurosci Biobehav Rev 2017; 76:336-362. [DOI: 10.1016/j.neubiorev.2016.06.002] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 05/06/2016] [Accepted: 06/06/2016] [Indexed: 01/12/2023]
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Abstract
Thanks to advances in neuroscience, addiction is now recognized as a chronic brain disease with genetic, developmental, and cultural components. Drugs of abuse, including alcohol, are able to produce significant neuroplastic changes responsible for the profound disturbances shown by drug addicted individuals. The current lack of efficacious pharmacological treatments for substance use disorders has encouraged the search for novel and more effective pharmacotherapies. Growing evidence strongly suggests that Sigma Receptors are involved in the addictive and neurotoxic properties of abused drugs, including cocaine , methamphetamine , and alcohol. The present chapter will review the current scientific knowledge on the role of the Sigma Receptor system in the effects of drugs and alcohol, and proposes that this receptor system may represent a novel therapeutic target for the treatment of substance use disorders and associated neurotoxicity.
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Weber F, Brust P, Laurini E, Pricl S, Wünsch B. Fluorinated PET Tracers for Molecular Imaging of σ 1 Receptors in the Central Nervous System. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 964:31-48. [PMID: 28315263 DOI: 10.1007/978-3-319-50174-1_4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
At first the role of σ1 receptors in various neurological, psychiatric and neurodegenerative disorders is discussed. In the second part, the principle of positron emission tomography (PET ) is described and the known fluorinated PET tracers for labeling of σ1 receptors are presented. The third part focuses on fluoroalkyl substituted spirocyclic PET tracers, which represent the most promising class of fluorinated PET tracers reported so far. The homologous fluoroalkyl derivatives 12-15 show high σ1 affinity (K i = 0.59-1.4 nM) and high selectivity over the σ2 subtype (408-1331-fold). The enantiomers of the fluoroethyl derivative fluspidine 13 were prepared and pharmacologically characterized. Whereas the (S)-configured enantiomer (S)-13 (K i = 2.3 nM) is 4-fold less active than the (R)-enantiomer (R)-13 (K i = 0.57 nM), (S)-13 is metabolically more stable. The interactions of (S)-13 and (R)-13 with the σ1 receptor were analyzed at the molecular level using the 3D homology model. In an automated radiosynthesis [18F](S)-13 and [18F](R)-13 were prepared by nucleophilic substitution of the tosylates (S)-17 and (R)-17 with K[18F]F in high radiochemical yield, high radiochemical purity and short reaction time. Application of both enantiomers [18F](S)-13 and [18F](R)-13 to mice and piglets led to fast uptake into the brain, but [18F](R)-13 did not show washout from the brain indicating a quasi-irreversible binding. Both radiotracers [18F](S)-13 and [18F](R)-13 were able to label regions in the mouse and piglet brain with high σ1 receptor density. The specific binding of the enantiomeric tracers [18F](S)-13 and [18F](R)-13 could be replaced by the selective σ1 ligand SA4503.
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Affiliation(s)
- Frauke Weber
- Institute of Pharmaceutical and Medicinal Chemistry, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, D-48149, Münster, Germany
| | - Peter Brust
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Permoserstraße 15, D-04318, Leipzig, Germany
| | - Erik Laurini
- Molecular Simulations Engineering (MOSE) Laboratory, Department of Engineering and Architecture (DEA), University of Trieste, Via Valerio 6, 34127, Trieste, Italy
| | - Sabrina Pricl
- Molecular Simulations Engineering (MOSE) Laboratory, Department of Engineering and Architecture (DEA), University of Trieste, Via Valerio 6, 34127, Trieste, Italy
- National Interuniversity Consortium for Material Science and Technology (INSTM), Research Unit MOSE-DEA, University of Trieste, Via Valerio 6, 32127, Trieste, Italy
| | - Bernhard Wünsch
- Institute of Pharmaceutical and Medicinal Chemistry, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, D-48149, Münster, Germany.
- Cells-in-Motion Cluster of Excellence (EXC 1003 - CiM), University Münster, Münster, Germany.
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Abstract
Although extensive research has focused on understanding the neurobiological mechanisms underlying alcohol addiction, pharmacological treatments for alcohol use disorders are very limited and not always effective. This constraint has encouraged the search for novel pharmacological targets for alcoholism therapy. Sigma receptors were shown to mediate some of the properties of cocaine and amphetamine, which was attributed to the direct binding of psychostimulants to these receptors. More recently, the role of sigma receptors in the rewarding and reinforcing effects of alcohol was also proposed, and it was suggested that their hyperactivity may result in excessive alcohol drinking. This chapter reviews current knowledge on the topic, and suggests that the sigma receptor system may represent a new therapeutic target for the treatment of alcohol use disorders.
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Affiliation(s)
- Valentina Sabino
- Laboratory of Addictive Disorders, Department of Pharmacology and Experimental Therapeutics and Department of Psychiatry, Boston University School of Medicine, Boston, MA, 02118, USA.
- Laboratory of Addictive Disorders, Boston University School of Medicine, 72 E Concord St, R-612, Boston, MA, 02118, USA.
| | - Pietro Cottone
- Laboratory of Addictive Disorders, Department of Pharmacology and Experimental Therapeutics and Department of Psychiatry, Boston University School of Medicine, Boston, MA, 02118, USA
- Laboratory of Addictive Disorders, Boston University School of Medicine, 72 E Concord St, R-612, Boston, MA, 02118, USA
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Valenza M, DiLeo A, Steardo L, Cottone P, Sabino V. Ethanol-related behaviors in mice lacking the sigma-1 receptor. Behav Brain Res 2016; 297:196-203. [PMID: 26462569 PMCID: PMC4679530 DOI: 10.1016/j.bbr.2015.10.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 10/01/2015] [Accepted: 10/05/2015] [Indexed: 01/01/2023]
Abstract
RATIONALE The Sigma-1 receptor (Sig-1R) is a chaperone protein that has been implicated in drug abuse and addiction. Multiple studies have characterized the role the Sig-1R plays in psychostimulant addiction; however, fewer studies have specifically investigated its role in alcohol addiction. We have previously shown that antagonism of the Sig-1R reduces excessive drinking and motivation to drink, whereas agonism induces binge-like drinking in rodents. OBJECTIVES The objectives of these studies were to investigate the impact of Sig-1R gene deletion in C57Bl/6J mice on ethanol drinking and other ethanol-related behaviors. METHODS We used an extensive panel of behavioral tests to examine ethanol actions in male, adult mice lacking Oprs1, the gene encoding the Sig-1R. To compare ethanol drinking behavior, Sig-1 knockout (KO) and wild type (WT) mice were subject to a two-bottle choice, continuous access paradigm with different concentrations of ethanol (3-20% v/v) vs. water. Consumption of sweet and bitter solutions was also assessed in Sig-1R KO and WT mice. Finally, motor stimulant sensitivity, taste aversion and ataxic effects of ethanol were assessed. RESULTS Sig-1R KO mice displayed higher ethanol intake compared to WT mice; the two genotypes did not differ in their sweet or bitter taste perception. Sig-1R KO mice showed lower sensitivity to ethanol stimulant effects, but greater sensitivity to its taste aversive effects. Ethanol-induced sedation was instead unaltered in the mutants. CONCLUSIONS Our results prove that the deletion of the Sig-1R increases ethanol consumption, likely by decreasing its rewarding effects, and therefore indicating that the Sig-1R is involved in modulation of the reinforcing effects of alcohol.
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Affiliation(s)
- Marta Valenza
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, Boston, MA, United States; Department of Biomedical Sciences and Human Oncology, University of Bari "Aldo Moro", Bari, Italy
| | - Alyssa DiLeo
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, Boston, MA, United States
| | - Luca Steardo
- Department of Physiology and Pharmacology "V. Erspamer", Sapienza University, Rome, Italy
| | - Pietro Cottone
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, Boston, MA, United States
| | - Valentina Sabino
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, Boston, MA, United States.
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Abstract
This review compares the biological and physiological function of Sigma receptors [σRs] and their potential therapeutic roles. Sigma receptors are widespread in the central nervous system and across multiple peripheral tissues. σRs consist of sigma receptor one (σ1R) and sigma receptor two (σ2R) and are expressed in numerous regions of the brain. The sigma receptor was originally proposed as a subtype of opioid receptors and was suggested to contribute to the delusions and psychoses induced by benzomorphans such as SKF-10047 and pentazocine. Later studies confirmed that σRs are non-opioid receptors (not an µ opioid receptor) and play a more diverse role in intracellular signaling, apoptosis and metabolic regulation. σ1Rs are intracellular receptors acting as chaperone proteins that modulate Ca2+ signaling through the IP3 receptor. They dynamically translocate inside cells, hence are transmembrane proteins. The σ1R receptor, at the mitochondrial-associated endoplasmic reticulum membrane, is responsible for mitochondrial metabolic regulation and promotes mitochondrial energy depletion and apoptosis. Studies have demonstrated that they play a role as a modulator of ion channels (K+ channels; N-methyl-d-aspartate receptors [NMDAR]; inositol 1,3,5 triphosphate receptors) and regulate lipid transport and metabolism, neuritogenesis, cellular differentiation and myelination in the brain. σ1R modulation of Ca2+ release, modulation of cardiac myocyte contractility and may have links to G-proteins. It has been proposed that σ1Rs are intracellular signal transduction amplifiers. This review of the literature examines the mechanism of action of the σRs, their interaction with neurotransmitters, pharmacology, location and adverse effects mediated through them.
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Affiliation(s)
- Colin G Rousseaux
- a Department of Pathology and Laboratory Medicine , University of Ottawa , Ottawa , ON , Canada and
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Blasio A, Valenza M, Iyer MR, Rice KC, Steardo L, Hayashi T, Cottone P, Sabino V. Sigma-1 receptor mediates acquisition of alcohol drinking and seeking behavior in alcohol-preferring rats. Behav Brain Res 2015; 287:315-22. [PMID: 25848705 PMCID: PMC4424067 DOI: 10.1016/j.bbr.2015.03.065] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 03/25/2015] [Accepted: 03/30/2015] [Indexed: 01/19/2023]
Abstract
Sigma-1 receptor (Sig-1R) has been proposed as a novel therapeutic target for drug and alcohol addiction. We have shown previously that Sig-1R agonists facilitate the reinforcing effects of ethanol and induce binge-like drinking, while Sig-1R antagonists on the other hand block excessive drinking in genetic and environmental models of alcoholism, without affecting intake in outbred non-dependent rats. Even though significant progress has been made in understanding the function of Sig-1R in alcohol reinforcement, its role in the early and late stage of alcohol addiction remains unclear. Administration of the selective Sig-1R antagonist BD-1063 dramatically reduced the acquisition of alcohol drinking behavior as well as the preference for alcohol in genetically selected TSRI Sardinian alcohol preferring (Scr:sP) rats; the treatment had instead no effect on total fluid intake, food intake or body weight gain, proving selectivity of action. Furthermore, BD-1063 dose-dependently decreased alcohol-seeking behavior in rats trained under a second-order schedule of reinforcement, in which responding is maintained by contingent presentation of a conditioned reinforcer. Finally, an innate elevation in Sig-1R protein levels was found in the nucleus accumbens of alcohol-preferring Scr:sP rats, compared to outbred Wistar rats, alteration which was normalized by chronic, voluntary alcohol drinking. Taken together these findings demonstrate that Sig-1R blockade reduces the propensity to both acquire alcohol drinking and to seek alcohol, and point to the nucleus accumbens as a potential key region for the effects observed. Our data suggest that Sig-1R antagonists may have therapeutic potential in multiple stages of alcohol addiction.
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Affiliation(s)
- Angelo Blasio
- Laboratory of Addictive Disorders, Departments of Pharmacology and Experimental Therapeutics and Department of Psychiatry, Boston University School of Medicine, Boston, MA, USA
| | - Marta Valenza
- Laboratory of Addictive Disorders, Departments of Pharmacology and Experimental Therapeutics and Department of Psychiatry, Boston University School of Medicine, Boston, MA, USA
| | - Malliga R Iyer
- Drug Design and Synthesis Section, Chemical Biology Research Branch, National Institute on Drug Abuse and National Institute on Alcohol Abuse and Alcoholism, National Institute of Health, Department of Health and Human Services, Bethesda, MD, USA
| | - Kenner C Rice
- Drug Design and Synthesis Section, Chemical Biology Research Branch, National Institute on Drug Abuse and National Institute on Alcohol Abuse and Alcoholism, National Institute of Health, Department of Health and Human Services, Bethesda, MD, USA
| | - Luca Steardo
- Department of Physiology and Pharmacology Vittorio Erspamer, Sapienza University of Rome, Rome, Italy
| | - T Hayashi
- Department of Medicine, Nishikawa Hospital, Hamada, Shimane, Japan
| | - Pietro Cottone
- Laboratory of Addictive Disorders, Departments of Pharmacology and Experimental Therapeutics and Department of Psychiatry, Boston University School of Medicine, Boston, MA, USA
| | - Valentina Sabino
- Laboratory of Addictive Disorders, Departments of Pharmacology and Experimental Therapeutics and Department of Psychiatry, Boston University School of Medicine, Boston, MA, USA.
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Yang L, Yao H, Chen X, Cai Y, Callen S, Buch S. Role of Sigma Receptor in Cocaine-Mediated Induction of Glial Fibrillary Acidic Protein: Implications for HAND. Mol Neurobiol 2015; 53:1329-1342. [PMID: 25631712 DOI: 10.1007/s12035-015-9094-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 01/12/2015] [Indexed: 12/01/2022]
Abstract
Cocaine abuse has been shown to accelerate the progression of human immunodeficiency virus (HIV)-1-associated neurological disorders (HANDs) partially through increasing neuroinflammatory response mediated by activated astrocytes; however, the detailed molecular mechanism of cocaine-mediated astrocyte activation is unclear. In the current study, we demonstrated increased astrogliosis in the cortical regions of brains from HIV(+) cocaine abusers compared with the HIV(+) group without cocaine abuse. We next sought to explore whether cocaine exposure could result in increased expression of glial fibrillary acidic protein (GFAP), a filament protein critical for astrocyte activation. Exposure of cocaine to astrocytes resulted in rapid translocation of sigma receptor to the plasma membrane with subsequent activation of downstream signaling pathways. Using a pharmacological approach, we provide evidence that cocaine-mediated upregulation of GFAP expression involved activation of mitogen-activated protein kinase (MAPK) signaling with subsequent downstream activation of the early growth response gene 1 (Egr-1). Egr-1 activation, in turn, caused transcriptional regulation of GFAP. Corroboration of these findings in vivo demonstrated increased expression of GFAP in the cortical region of mice treated with cocaine compared with the saline injected controls. A thorough understanding of how cocaine mediates astrogliosis could have implications for the development of therapeutic interventions aimed at HIV-infected cocaine abusers.
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Affiliation(s)
- Lu Yang
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Honghong Yao
- Department of Pharmacology, Medical School of Southeast University, Nanjing, 210009, Jiangsu, China
| | - Xufeng Chen
- The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, China
| | - Yu Cai
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Shannon Callen
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Shilpa Buch
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, 68198, USA.
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Tsai SYA, Pokrass MJ, Klauer NR, De Credico NE, Su TP. Sigma-1 receptor chaperones in neurodegenerative and psychiatric disorders. Expert Opin Ther Targets 2014; 18:1461-76. [PMID: 25331742 PMCID: PMC5518923 DOI: 10.1517/14728222.2014.972939] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
INTRODUCTION Sigma-1 receptors (Sig-1Rs) are molecular chaperones that reside mainly in the endoplasmic reticulum (ER) but exist also in the proximity of the plasma membrane. Sig-1Rs are highly expressed in the CNS and are involved in many cellular processes including cell differentiation, neuritogenesis, microglia activation, protein quality control, calcium-mediated ER stress and ion channel modulation. Disturbance in any of the above cellular processes can accelerate the progression of many neurological disorders; therefore, the Sig-1R has been implicated in several neurological diseases. AREAS COVERED This review broadly covers the functions of Sig-1Rs including several neurodegenerative disorders in humans and drug addiction-associated neurological disturbance in the case of HIV infection. We discuss how several Sig-1R ligands could be utilized in therapeutic approaches to treat those disorders. EXPERT OPINION Emerging understanding of the cellular functions of this unique transmembrane chaperone may lead to the use of new agents or broaden the use of certain available ligands as therapeutic targets in those neurological disorders.
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Affiliation(s)
- Shang-Yi A Tsai
- National Institute on Drug Abuse, National Institutes of Health, Cellular Pathobiology Section, Integral Neuroscience Branch , Baltimore, MD 21224 , USA ;
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Dore R, Valenza M, Wang X, Rice KC, Sabino V, Cottone P. The inverse agonist of CB1 receptor SR141716 blocks compulsive eating of palatable food. Addict Biol 2014; 19:849-61. [PMID: 23587012 DOI: 10.1111/adb.12056] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Dieting and the increased availability of highly palatable food are considered major contributing factors to the large incidence of eating disorders and obesity. This study was aimed at investigating the role of the cannabinoid (CB) system in a novel animal model of compulsive eating, based on a rapid palatable diet cycling protocol. Male Wistar rats were fed either continuously a regular chow diet (Chow/Chow, control group) or intermittently a regular chow diet for 2 days and a palatable, high-sucrose diet for 1 day (Chow/Palatable). Chow/Palatable rats showed spontaneous and progressively increasing hypophagia and body weight loss when fed the regular chow diet, and excessive food intake and body weight gain when fed the palatable diet. Diet-cycled rats dramatically escalated the intake of the palatable diet during the first hour of renewed access (7.5-fold compared to controls), and after withdrawal, they showed compulsive eating and heightened risk-taking behavior. The inverse agonist of the CB1 receptor, SR141716 reduced the excessive intake of palatable food with higher potency and the body weight with greater efficacy in Chow/Palatable rats, compared to controls. Moreover, SR141716 reduced compulsive eating and risk-taking behavior in Chow/Palatable rats. Finally, consistent with the behavioral and pharmacological observations, withdrawal from the palatable diet decreased the gene expression of the enzyme fatty acid amide hydrolase in the ventromedial hypothalamus while increasing that of CB1 receptors in the dorsal striatum in Chow/Palatable rats, compared to controls. These findings will help understand the role of the CB system in compulsive eating.
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Affiliation(s)
- Riccardo Dore
- Laboratory of Addictive Disorders; Departments of Pharmacology and Psychiatry; Boston University School of Medicine; Boston MA USA
| | - Marta Valenza
- Laboratory of Addictive Disorders; Departments of Pharmacology and Psychiatry; Boston University School of Medicine; Boston MA USA
- Department of Biomedical Sciences and Human Oncology; University of Bari Aldo Moro; Bari Italy
| | - Xiaofan Wang
- Laboratory of Addictive Disorders; Departments of Pharmacology and Psychiatry; Boston University School of Medicine; Boston MA USA
| | - Kenner C. Rice
- Chemical Biology Research Branch; National Institute on Drug Abuse and National Institute on Alcohol and Alcoholism; Rockville MD USA
| | - Valentina Sabino
- Laboratory of Addictive Disorders; Departments of Pharmacology and Psychiatry; Boston University School of Medicine; Boston MA USA
| | - Pietro Cottone
- Laboratory of Addictive Disorders; Departments of Pharmacology and Psychiatry; Boston University School of Medicine; Boston MA USA
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Blasio A, Steardo L, Sabino V, Cottone P. Opioid system in the medial prefrontal cortex mediates binge-like eating. Addict Biol 2014; 19:652-62. [PMID: 23346966 DOI: 10.1111/adb.12033] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Binge eating disorder is an addiction-like disorder characterized by excessive food consumption within discrete periods of time. This study was aimed at understanding the role of the opioid system within the medial prefrontal cortex (mPFC) in the consummatory and motivational aspects of binge-like eating. For this purpose, we trained male rats to obtain either a sugary, highly palatable diet (Palatable rats) or a chow diet (Chow rats) for 1 hour/day. We then evaluated the effects of the opioid receptor antagonist, naltrexone, given either systemically or site-specifically into the nucleus accumbens (NAcc) or the mPFC on a fixed ratio 1 (FR1) and a progressive ratio schedule of reinforcement for food. Finally, we assessed the expression of the genes proopiomelanocortin (POMC), pro-dynorphin (PDyn) and pro-enkephalin (PEnk), coding for the opioids peptides in the NAcc and the mPFC in both groups. Palatable rats rapidly escalated their intake by four times. Naltrexone, when administered systemically and into the NAcc, reduced FR1 responding for food and motivation to eat under a progressive ratio in both Chow and Palatable rats; conversely, when administered into the mPFC, the effects were highly selective for binge eating rats. Furthermore, we found a twofold increase in POMC and a ∼50% reduction in PDyn gene expression in the mPFC of Palatable rats, when compared to control rats; however, no changes were observed in the NAcc. Our data suggest that neuroadaptations of the opioid system in the mPFC occur following intermittent access to highly palatable food, which may be responsible for the development of binge-like eating.
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Affiliation(s)
- Angelo Blasio
- Laboratory of Addictive Disorders; Departments of Pharmacology and Psychiatry; Boston University School of Medicine; Boston MA USA
| | - Luca Steardo
- Department of Physiology and Pharmacology; University of Rome ‘Sapienza’; Italy
| | - Valentina Sabino
- Laboratory of Addictive Disorders; Departments of Pharmacology and Psychiatry; Boston University School of Medicine; Boston MA USA
| | - Pietro Cottone
- Laboratory of Addictive Disorders; Departments of Pharmacology and Psychiatry; Boston University School of Medicine; Boston MA USA
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Matsumoto RR, Nguyen L, Kaushal N, Robson MJ. Sigma (σ) receptors as potential therapeutic targets to mitigate psychostimulant effects. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2014; 69:323-86. [PMID: 24484982 DOI: 10.1016/b978-0-12-420118-7.00009-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Many psychostimulants, including cocaine and methamphetamine, interact with sigma (σ) receptors at physiologically relevant concentrations. The potential therapeutic relevance of this interaction is underscored by the ability to selectively target σ receptors to mitigate many behavioral and physiological effects of psychostimulants in animal and cell-based model systems. This chapter begins with an overview of these enigmatic proteins. Provocative preclinical data showing that σ ligands modulate an array of cocaine and methamphetamine effects are summarized, along with emerging areas of research. Together, the literature suggests targeting of σ receptors as an innovative option for combating undesired actions of psychostimulants through both neuronal and glial mechanisms.
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Affiliation(s)
- Rae R Matsumoto
- West Virginia University, One Medical Center Drive, Morgantown, West Virginia, USA.
| | - Linda Nguyen
- West Virginia University, One Medical Center Drive, Morgantown, West Virginia, USA
| | - Nidhi Kaushal
- West Virginia University, One Medical Center Drive, Morgantown, West Virginia, USA
| | - Matthew J Robson
- West Virginia University, One Medical Center Drive, Morgantown, West Virginia, USA
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Butler TR, Chappell AM, Weiner JL. Effect of β3 adrenoceptor activation in the basolateral amygdala on ethanol seeking behaviors. Psychopharmacology (Berl) 2014; 231:293-303. [PMID: 23955701 PMCID: PMC3877711 DOI: 10.1007/s00213-013-3238-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Accepted: 07/31/2013] [Indexed: 01/15/2023]
Abstract
RATIONALE The interaction between ethanol (EtOH) and anxiety plays an integral role in the development and maintenance of alcoholism. Many medications in pre-clinical or clinical trials for the treatment of alcoholism share anxiolytic properties. However, these drugs typically have untoward side effects, such as sedation or impairment of motor function that may limit their clinical use. We have recently demonstrated that BRL 37344 (BRL), a selective β3-adrenoceptor (AR) agonist, enhances a discrete population of GABAergic synapses in the basolateral amygdala (BLA) that mediates feed-forward inhibition from lateral paracapsular (LPC) GABAergic interneurons onto BLA pyramidal cells. Behavioral studies revealed that intra-BLA infusion of BRL significantly reduced measures of unconditioned anxiety-like behavior without locomotor depressant effects. OBJECTIVES The present studies tested the effect of BRL (0.1, 0.5, or 1.0 μg/side) on EtOH self-administration using an intermittent access home cage two-bottle choice procedure and limited access operant responding for EtOH or sucrose. RESULTS Intra-BLA infusion of BRL did not reduce home cage, intermittent EtOH self-administration. However, using an operant procedure that permits the discrete assessment of appetitive (seeking) and consummatory measures of EtOH self-administration, BRL reduced measures of EtOH and sucrose seeking, but selectively reduced operant responding for EtOH during extinction probe trials. BRL had no effect on consummatory behaviors for EtOH or sucrose. CONCLUSIONS Together, these data suggest that intra-BLA infusion of BRL significantly reduces motivation to seek EtOH and provide initial evidence that β3-ARs and LPC GABAergic synapses may represent promising targets for the development of novel pharmacotherapies for the treatment of alcoholism.
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Affiliation(s)
- T R Butler
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC, 27157, USA
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Dissociable effects of kappa-opioid receptor activation on impulsive phenotypes in wistar rats. Neuropsychopharmacology 2013; 38:2278-85. [PMID: 23689673 PMCID: PMC3773679 DOI: 10.1038/npp.2013.129] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Revised: 05/07/2013] [Accepted: 05/08/2013] [Indexed: 02/06/2023]
Abstract
The kappa-opioid receptor (KOR) is the primary target for the endogenous opioid peptide dynorphin (DYN), and KORs reside within brain circuitry underlying the complex integration of information related to different behavioral domains such as motivation, negative affect, and decision-making. Alterations in extended amygdala DYNs and KOR function following chronic alcohol exposure have been shown to mediate escalated alcohol self-administration during acute withdrawal. In addition to excessive alcohol consumption and increased negative affect, other symptoms of alcohol dependence include compromised impulse control. Given that DYN and KOR expressions are dysregulated within prefrontal brain circuitry associated with decision-making and impulse control in alcohol-dependent humans and rodents, and have been shown to modify multiple neurotransmitter systems associated with impulse-control disorders, we hypothesized that KOR activation could contribute to impulsive phenotypes. To test this hypothesis, separate cohorts of male Wistar rats were trained in one of the two animal models of impulsivity: delay-discounting (DD) or stop-signal reaction time (SSRT) tasks, and once stable responding was observed, received intracerebroventricular (ICV) infusions of the KOR agonist U50,488 (0-50 μg) according to a within-subject dosing regimen. The results demonstrated a dissociable effect of U50,488 on impulsive phenotypes related to intolerance to delay or response inhibition, with selective effects in the SSRT. Furthermore, the pro-impulsive effects of KOR activation were rescued by pretreatment with the KOR antagonist nor-binaltorphimine (nor-BNI). Therefore, KOR activation was shown to induce an impulsive phenotype that was nor-BNI-sensitive. Dysregulation of impulsive behavior by increased DYN/KOR activity could serve to increase vulnerability for the initiation, or perpetuate existing patterns of excessive alcohol abuse and can enhance the probability of relapse in dependent individuals. Furthermore, KOR-mediated impulsivity has implications for numerous neuropsychiatric disorders.
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CRF mediates the anxiogenic and anti-rewarding, but not the anorectic effects of PACAP. Neuropsychopharmacology 2013; 38:2160-9. [PMID: 23657440 PMCID: PMC3773665 DOI: 10.1038/npp.2013.113] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 05/03/2013] [Accepted: 05/03/2013] [Indexed: 01/23/2023]
Abstract
Anxiety disorders represent the most common mental disturbances in the world, and they are characterized by an abnormal response to stress. Pituitary adenylate cyclase-activating polypeptide (PACAP) and its receptor PAC1 have been proposed to have a key role in mediating the responses to stress as well as the regulation of food intake and body weight. Corticotropin-releasing factor (CRF), the major stress peptide in the brain, has been hypothesized to be involved in PACAP effects, but the reports are conflicting so far. The present study was aimed at further characterizing the behavioral effects of PACAP in rats and at determining the role of central CRF receptors. We found that intracerebroventricular PACAP treatment induced anxiety-like behavior in the elevated plus maze test and elevated intracranial self-stimulation thresholds; both of these effects were fully blocked by concurrent treatment with the CRF receptor antagonist D-Phe-CRF(12-41). Interestingly, the CRF antagonist had no effect on PACAP-induced increased plasma corticosterone, reduction of food intake, and body weight loss. Finally, we found that PACAP increased CRF levels in the paraventricular nucleus of the hypothalamus and, importantly, in the central nucleus of the amygdala, as measured by solid phase radioimmunoassay and quantitative real-time PCR. Our results strengthen the notion that PACAP is a strong mediator of the behavioral response to stress and prove for the first time that this neuropeptide has anti-rewarding (ie, pro-depressant) effects. In addition, we identified the mechanism by which PACAP exerts its anxiogenic and pro-depressant effects, via the recruitment of the central CRF system and independently from HPA axis activation.
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Sabino V, Narayan AR, Zeric T, Steardo L, Cottone P. mTOR activation is required for the anti-alcohol effect of ketamine, but not memantine, in alcohol-preferring rats. Behav Brain Res 2013; 247:9-16. [PMID: 23466691 DOI: 10.1016/j.bbr.2013.02.030] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Revised: 02/23/2013] [Accepted: 02/25/2013] [Indexed: 02/06/2023]
Abstract
Glutamate NMDA receptors mediate many molecular and behavioral effects of alcohol, and they play a key role in the development of excessive drinking. Uncompetitive NMDA receptor antagonists may, therefore, have therapeutic potential for alcoholism. The first aim was to compare the effects of the NMDA antagonists memantine and ketamine on ethanol and saccharin drinking in alcohol-preferring rats. The second aim was to determine whether the effects of the two NMDA receptor antagonists were mediated by the mammalian target of rapamycin (mTOR). TSRI Sardinian alcohol-preferring rats were allowed to self-administer either 10% w/v ethanol or 0.08% w/v saccharin, and water. Operant responding and motor activity were assessed following administration of either memantine (0-10mg/kg) or ketamine (0-20mg/kg). Finally, ethanol self-administration was assessed in rats administered with either memantine or ketamine but pretreated with the mTOR inhibitor rapamycin (2.5mg/kg). The uncompetitive NMDA receptor antagonists memantine and ketamine dose-dependently reduced ethanol drinking in alcohol-preferring rats; while memantine had a preferential effect on alcohol over saccharin, ketamine reduced responding for both solutions. Neither antagonist induced malaise, as shown by the lack of effect on water intake and motor activity. The mTOR inhibitor rapamycin blocked the effects of ketamine, but not those of memantine. Memantine and ketamine both reduce alcohol drinking in alcohol-preferring rats, but only memantine is selective for alcohol. The effects of ketamine, but not memantine, are mediated by mTOR. The results support the therapeutic potential of uncompetitive NMDA receptor antagonists, especially memantine, in alcohol addiction.
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Affiliation(s)
- Valentina Sabino
- Laboratory of Addictive Disorders (LAD), Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA 02118, USA.
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Cottone P, Iemolo A, Narayan AR, Kwak J, Momaney D, Sabino V. The uncompetitive NMDA receptor antagonists ketamine and memantine preferentially increase the choice for a small, immediate reward in low-impulsive rats. Psychopharmacology (Berl) 2013; 226:127-38. [PMID: 23104264 PMCID: PMC3572289 DOI: 10.1007/s00213-012-2898-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Accepted: 09/23/2012] [Indexed: 02/04/2023]
Abstract
RATIONALE Impulsive behavior is categorically differentiated between impulsive action, the inability to withhold from acting out a response, and impulsive choice, the greater preference for an immediate and smaller reward over a delayed but more advantageous reward. While the effects of N-methyl-D-aspartic acid (NMDA) receptor antagonists on impulsive action have been extensively characterized, there are very few and conflicting reports on the effects of this class of drugs on impulsive choice. OBJECTIVES Using a modified adjusting delay task, we investigated the effects of uncompetitive and competitive blockade of NMDA receptors on impulsive choice. METHODS Male Wistar rats were trained in a modified adjusting delay task, which involved repeated choice between a low reinforcing solution delivered immediately and a highly reinforcing solution delivered after a variable delay. Rats were then administered either the NMDA receptor uncompetitive antagonists ketamine or memantine, or the competitive antagonists D-AP-5 or CGS 19755. RESULTS Ketamine treatment dose-dependently increased impulsive choice, and this effect was selective for low-impulsive but not high-impulsive rats. Similarly, memantine treatment dose-dependently increased impulsive choice with a preferential effect for low-impulsive rats. While D-AP-5 treatment did not affect impulsive choice, CGS 19755 increased impulsivity, however, at the same doses at which it caused a marked response inhibition. CONCLUSIONS NMDA receptor uncompetitive, but not competitive, antagonists significantly increased impulsive choice, preferentially in low-impulsive rats. These findings demonstrate that the effects of NMDA receptor blockade on impulsive choice are not generalizable and depend on the specific mechanism of action of the antagonist used.
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Affiliation(s)
- Pietro Cottone
- Department of Pharmacology, Laboratory of Addictive Disorders, Boston University School of Medicine, 72 E Concord St., R-618, Boston, MA 02118, USA. Department of Psychiatry, Laboratory of Addictive Disorders, Boston University School of Medicine, 72 E Concord St., R-618, Boston, MA 02118, USA
| | - Attilio Iemolo
- Department of Pharmacology, Laboratory of Addictive Disorders, Boston University School of Medicine, 72 E Concord St., R-618, Boston, MA 02118, USA. Department of Psychiatry, Laboratory of Addictive Disorders, Boston University School of Medicine, 72 E Concord St., R-618, Boston, MA 02118, USA
| | - Aditi R. Narayan
- Department of Pharmacology, Laboratory of Addictive Disorders, Boston University School of Medicine, 72 E Concord St., R-618, Boston, MA 02118, USA. Department of Psychiatry, Laboratory of Addictive Disorders, Boston University School of Medicine, 72 E Concord St., R-618, Boston, MA 02118, USA
| | - Jina Kwak
- Department of Pharmacology, Laboratory of Addictive Disorders, Boston University School of Medicine, 72 E Concord St., R-618, Boston, MA 02118, USA. Department of Psychiatry, Laboratory of Addictive Disorders, Boston University School of Medicine, 72 E Concord St., R-618, Boston, MA 02118, USA
| | - Duncan Momaney
- Department of Pharmacology, Laboratory of Addictive Disorders, Boston University School of Medicine, 72 E Concord St., R-618, Boston, MA 02118, USA. Department of Psychiatry, Laboratory of Addictive Disorders, Boston University School of Medicine, 72 E Concord St., R-618, Boston, MA 02118, USA
| | - Valentina Sabino
- Department of Pharmacology, Laboratory of Addictive Disorders, Boston University School of Medicine, 72 E Concord St., R-618, Boston, MA 02118, USA. Department of Psychiatry, Laboratory of Addictive Disorders, Boston University School of Medicine, 72 E Concord St., R-618, Boston, MA 02118, USA
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Cottone P, Wang X, Park JW, Valenza M, Blasio A, Kwak J, Iyer MR, Steardo L, Rice KC, Hayashi T, Sabino V. Antagonism of sigma-1 receptors blocks compulsive-like eating. Neuropsychopharmacology 2012; 37:2593-604. [PMID: 22713906 PMCID: PMC3473342 DOI: 10.1038/npp.2012.89] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2011] [Revised: 05/02/2012] [Accepted: 05/07/2012] [Indexed: 11/08/2022]
Abstract
Binge eating disorder is an addiction-like disorder characterized by episodes of rapid and excessive food consumption within discrete periods of time which occur compulsively despite negative consequences. This study was aimed at determining whether antagonism of Sigma-1 receptors (Sig-1Rs) blocked compulsive-like binge eating. We trained male wistar rats to obtain a sugary, highly palatable diet (Palatable group) or a regular chow diet (Chow control group), for 1 h a day under fixed ratio 1 operant conditioning. Following intake stabilization, we evaluated the effects of the selective Sig-1R antagonist BD-1063 on food responding. Using a light/dark conflict test, we also tested whether BD-1063 could block the time spent and the food eaten in an aversive, open compartment, where the palatable diet was offered. Furthermore, we measured Sig-1R mRNA and protein expression in several brain areas of the two groups, 24 h after the last binge session. Palatable rats rapidly developed binge-like eating, escalating the 1 h intake by four times, and doubling the eating rate and the regularity of food responding, compared to Chow rats. BD-1063 dose-dependently reduced binge-like eating and the regularity of food responding, and blocked the increased eating rate in Palatable rats. In the light/dark conflict test, BD-1063 antagonized the increased time spent in the aversive compartment and the increased intake of the palatable diet, without affecting motor activity. Finally, Palatable rats showed reduced Sig-1R mRNA expression in prefrontal and anterior cingulate cortices, and a two-fold increase in Sig-1R protein expression in anterior cingulate cortex compared to control Chow rats. These findings suggest that the Sig-1R system may contribute to the neurobiological adaptations driving compulsive-like eating, opening new avenues of investigation towards pharmacologically treating binge eating disorder.
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Affiliation(s)
- Pietro Cottone
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, Boston, MA, USA
| | - Xiaofan Wang
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, Boston, MA, USA
| | - Jin Won Park
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, Boston, MA, USA
| | - Marta Valenza
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, Boston, MA, USA
- Department of Pharmacology and Human Physiology, School of Medicine, University of Bari, Bari, Italy
| | - Angelo Blasio
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, Boston, MA, USA
- Department of Physiology and Pharmacology, University of Rome La Sapienza, Rome, Italy
| | - Jina Kwak
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, Boston, MA, USA
| | - Malliga R Iyer
- Chemical Biology Research Branch, National Institute on Drug Abuse and the National Institute on Alcohol Abuse and Alcoholism, Rockville, MD, USA
| | - Luca Steardo
- Department of Physiology and Pharmacology, University of Rome La Sapienza, Rome, Italy
| | - Kenner C Rice
- Chemical Biology Research Branch, National Institute on Drug Abuse and the National Institute on Alcohol Abuse and Alcoholism, Rockville, MD, USA
| | - Teruo Hayashi
- Cellular Stress Signaling Unit, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, USA
| | - Valentina Sabino
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, Boston, MA, USA
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Martin-Fardon R, Strong EM, Weiss F. Effect of σ1 receptor antagonism on ethanol and natural reward seeking. Neuroreport 2012; 23:809-13. [DOI: 10.1097/wnr.0b013e32835717c8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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Ogawa K, Kanbara H, Shiba K, Kitamura Y, Kozaka T, Kiwada T, Odani A. Development and evaluation of a novel radioiodinated vesamicol analog as a sigma receptor imaging agent. EJNMMI Res 2012; 2:54. [PMID: 23021206 PMCID: PMC3524758 DOI: 10.1186/2191-219x-2-54] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Accepted: 08/14/2012] [Indexed: 12/13/2022] Open
Abstract
UNLABELLED BACKGROUND Sigma receptors are highly expressed in human tumors and should be appropriate targets for developing tumor imaging agents. Previously, we synthesized a vesamicol analog, (+)-2-[4-(4-iodophenyl)piperidino]cyclohexanol ((+)-pIV), with a high affinity for sigma receptors and prepared radioiodinated (+)-pIV. As a result, (+)-[125I]pIV showed high tumor uptake in biodistribution experiments. However, the accumulation of radioactivity in normal tissues, such as the liver, was high. We supposed that some parts of the accumulation of (+)-pIV in the liver should be because of its high lipophilicity, and prepared and evaluated a more hydrophilic radiolabeled vesamicol analog, (+)-4-[1-(2-hydroxycyclohexyl)piperidine-4-yl]-2-iodophenol ((+)-IV-OH). METHODS (+)-[125I]IV-OH was prepared by the chloramine T method from the precursor. The partition coefficient of (+)-[125I]IV-OH was measured. Biodistribution experiments were performed by intravenous administration of a mixed solution of (+)-[125I]IV-OH and (+)-[131I]pIV into DU-145 tumor-bearing mice. Blocking studies were performed by intravenous injection of (+)-[125I]IV-OH mixed with an excess amount of ligand into DU-145 tumor-bearing mice. RESULTS The hydrophilicity of (+)-[125I]IV-OH was much higher than that of (+)-[125I]pIV. In biodistribution experiments, (+)-[125I]IV-OH and (+)-[131I]pIV showed high uptake in tumor tissues at 10-min post-injection. Although (+)-[131I]pIV tended to be retained in most tissues, (+)-[125I]IV-OH was cleared from most tissues. In the liver, the radioactivity level of (+)-[125I]IV-OH was significantly lower at all time points compared to those of (+)-[131I]pIV. In the blocking studies, co-injection of an excess amount of sigma ligands resulted in significant decreases of tumor/blood uptake ratios after injection of (+)-[125I]IV-OH. CONCLUSIONS The results indicate that radioiodinated (+)-IV-OH holds a potential as a sigma receptor imaging agent.
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Affiliation(s)
- Kazuma Ogawa
- Division of Pharmaceutical Sciences, Graduate School of Medical Sciences, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan.
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Iemolo A, Valenza M, Tozier L, Knapp CM, Kornetsky C, Steardo L, Sabino V, Cottone P. Withdrawal from chronic, intermittent access to a highly palatable food induces depressive-like behavior in compulsive eating rats. Behav Pharmacol 2012; 23:593-602. [PMID: 22854309 PMCID: PMC3934429 DOI: 10.1097/fbp.0b013e328357697f] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The increased availability of highly palatable foods is a major contributing factor toward the development of compulsive eating in obesity and eating disorders. It has been proposed that compulsive eating may develop as a form of self-medication to alleviate the negative emotional state associated with withdrawal from highly palatable foods. This study was aimed at determining whether withdrawal from chronic, intermittent access to a highly palatable food was responsible for the emergence of depressive-like behavior. For this purpose, a group of male Wistar rats was provided a regular chow diet 7 days a week (Chow/Chow), whereas a second group of rats was provided chow for 5 days a week, followed by a 2-day access to a highly palatable sucrose diet (Chow/Palatable). Following 7 weeks of diet alternation, depressive-like behavior was assessed during withdrawal from the highly palatable diet and following renewed access to it, using the forced swim test, the sucrose consumption test, and the intracranial self-stimulation threshold procedure. It was found that Chow/Palatable rats withdrawn from the highly palatable diet showed increased immobility time in the forced swim test and decreased sucrose intake in the sucrose consumption test compared with the control Chow/Chow rats. Interestingly, the increased immobility in the forced swim test was abolished by renewing access to the highly palatable diet. No changes were observed in the intracranial self-stimulation threshold procedure. These results validate the hypothesis that withdrawal from highly palatable food is responsible for the emergence of depressive-like behavior, and they also show that compulsive eating relieves the withdrawal-induced negative emotional state.
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Affiliation(s)
- Attilio Iemolo
- Laboratory of Addictive Disorders, Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, Massachusetts, USA
- Department of Psychiatry, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Marta Valenza
- Laboratory of Addictive Disorders, Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, Massachusetts, USA
- Department of Psychiatry, Boston University School of Medicine, Boston, Massachusetts, USA
- Department of Pharmacology and Human Physiology, University of Bari, Bari
| | - Lisa Tozier
- Department of Psychiatry, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Clifford M. Knapp
- Department of Psychiatry, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Conan Kornetsky
- Department of Psychiatry, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Luca Steardo
- Department of Physiology and Pharmacology, University of Rome La Sapienza, Rome, Italy
| | - Valentina Sabino
- Laboratory of Addictive Disorders, Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, Massachusetts, USA
- Department of Psychiatry, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Pietro Cottone
- Laboratory of Addictive Disorders, Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, Massachusetts, USA
- Department of Psychiatry, Boston University School of Medicine, Boston, Massachusetts, USA
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Lever SZ, Xu R, Fan KH, Fergason-Cantrell EA, Carmack TL, Watkinson LD, Lever JR. Synthesis, radioiodination and in vitro and in vivo sigma receptor studies of N-1-allyl-N´-4-phenethylpiperazine analogs. Nucl Med Biol 2012; 39:401-14. [PMID: 22172395 DOI: 10.1016/j.nucmedbio.2011.10.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Revised: 08/25/2011] [Accepted: 10/05/2011] [Indexed: 10/14/2022]
Abstract
INTRODUCTION Sigma-1 (σ(1)) receptor radioligands are useful for basic pharmacology studies and for imaging studies in neurology, psychiatry and oncology. We derived a hybrid structure, N-1-allyl-N´-4-phenethylpiperazine, from known ligands TPCNE and SA4503 for use as a scaffold for development of radioiodinated σ(1) receptor ligands. METHODS E-and Z-N-1-(3'-iodoallyl)-N´-4-(3″,4″-dimethoxyphenethyl)-piperazine (E-1 and Z-1), N-1-allyl-N´-4-(3',4'-dimethoxyphenethyl)-piperazine (2) and E-N-1-(3'-iodoallyl)-N´-4-(3″-methoxy-4'´-hydroxyphenethyl)-piperazine (3) were synthesized. Affinities for σ(1) and σ(2) receptors were determined. [(125)I]E-1 and [(125)I]Z-1 were prepared and evaluated in vivo in mice. [(125)I]E-1 was further evaluated in σ(1) receptor binding assays in vitro. RESULTS E-1 displayed moderately high apparent affinity (15 nM) for σ(1) sites and 84-fold selectivity against σ(2) sites. Z-1 showed similar σ(1) affinity, but only 23-fold selectivity. In contrast, 2 exhibited poor binding to both subtypes, while 3 had good affinities but poor selectivity. E-1 profiled as a probable antagonist in the phenytoin shift assay. [(125)I]E-1 and [(125)I]Z-1 were prepared in good yields and with high specific radioactivities. Log D(7.4) values (2.25 and 2.27) fall within the optimal range for in vivo studies. Both radioligands selectively labeled σ(1) receptors in mouse brain and peripheral organs in vivo. [(125)I]E-1 showed a higher level of specific binding than [(125)I]Z-1 and displayed good metabolic stability. Further, [(125)I]E-1 selectively labeled σ(1) receptors in mouse brain homogenates (K(d) 3.79 nM; B(max)=599 fmol/mg protein). CONCLUSIONS [(125)I]E-1 is a selective σ(1) receptor radioligand that exhibits properties amenable to in vitro and in vivo studies, with possible extension to single photon emission computed tomography using iodine-123.
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Affiliation(s)
- Susan Z Lever
- Department of Chemistry, University of Missouri-Columbia, Columbia, MO 65211, USA.
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Finger BC, Dinan TG, Cryan JF. Diet-induced obesity blunts the behavioural effects of ghrelin: studies in a mouse-progressive ratio task. Psychopharmacology (Berl) 2012; 220:173-81. [PMID: 21892647 DOI: 10.1007/s00213-011-2468-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Accepted: 08/22/2011] [Indexed: 10/17/2022]
Abstract
RATIONAL The ghrelinergic system is implicated in the development of obesity and in modulating central reward systems. It has been reported that diet-induced obesity causes blunted responding on food intake to ghrelin administration, associated with central ghrelin resistance. Here we investigate whether the stimulatory effects of ghrelin on the reward system are altered in diet-induced obese mice. METHODS Obesity was induced in C57BL/6J mice by feeding high-fat diet for 13 weeks. Mice were trained in an operant fixed and exponential progressive ratio task to respond for sucrose rewards. In an ad libitum fed state, ghrelin and a ghrelin receptor antagonist were administered in the progressive ratio. Alterations in the central ghrelin system in diet-induced obese mice were assessed. RESULTS Obese mice showed attenuated acquisition and performance in the fixed and progressive ratio paradigm. Most importantly, diet-induced obesity inhibited the stimulatory effects of ghrelin (2 nmol, 3 nmol/10 g) on progressive ratio responding whereas lean animals presented with increased responding. Administration of the ghrelin-receptor antagonist (D-Lys(3))-GHRP-6 (66.6 nmol/10 g) decreased performance in lean but not obese mice. This insensitivity to ghrelin receptor ligands in mice on high-fat diet was further supported by decreased mRNA expression of the ghrelin receptor in the hypothalamus and the nucleus accumbens in obese mice. CONCLUSIONS This study demonstrates that the modulatory effects of ghrelin receptor ligands are blunted in a mouse model of diet-induced obesity in a progressive ratio task. Thereby, our data extend the previously described ghrelin resistance in these mice from food intake to reward-associated behaviours.
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Affiliation(s)
- Beate C Finger
- Food for Health Ireland, University College Cork, Cork, Ireland
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A modified adjusting delay task to assess impulsive choice between isocaloric reinforcers in non-deprived male rats: effects of 5-HT₂A/C and 5-HT₁A receptor agonists. Psychopharmacology (Berl) 2012; 219:377-86. [PMID: 21989803 PMCID: PMC3936353 DOI: 10.1007/s00213-011-2517-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Accepted: 09/14/2011] [Indexed: 10/17/2022]
Abstract
RATIONALE Existing animal models of impulsivity frequently use food restriction to increase subjects' motivation. In addition, behavioral tasks that assess impulsive choice typically involve the use of reinforcers with dissimilar caloric content. These factors represent energy-homeostasis limitations, which may confound the interpretation of results and limit the applicability of these models. OBJECTIVES This study was aimed at validating face and convergent validities of a modified adjusting delay task, which assesses impulsive choice between isocaloric reinforcers in ad libitum fed rats. METHODS Male Wistar rats (n = 18) were used to assess the preferredness and reinforcing efficacy of a "supersaccharin" solution (1.5% glucose/0.4% saccharin) over a 1.5% glucose solution. A separate group of rats (n = 24) was trained in a modified adjusting delay task, which involved repeated choice between the glucose solution delivered immediately and the supersaccharin solution delivered after a variable delay. To pharmacologically validate the task, the effects of the 5-HT(2A/C) receptor agonist (±)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane [(±)-DOI] and the 5-HT(1A) receptor agonist (±)-8-hydroxy-2-(dipropylamino)tetralin hydrobromide [(±)-8-OH-DPAT] on impulsive choice were then evaluated. RESULTS Supersaccharin was highly reinforcing and uniformly preferred over the glucose solution by all subjects. Rats quickly learned the task, and impulsivity was a very stable and consistent trait. DOI and 8-OH-DPAT significantly and dose dependently increased impulsive choice in this modified adjusting delay task. CONCLUSIONS We validated a rodent task of impulsive choice, which eliminates typical energy-homeostasis limitations and, therefore, opens new avenues in the study of impulsivity in preclinical feeding and obesity research.
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Fitzsimmons JM, Lever JR, Lever SZ. Synthesis and σ 1 Receptor Binding of Halogenated N,N'-Diphenethylethylenediamines. Med Chem 2011; 1. [PMID: 23565348 DOI: 10.4172/2161-0444.1000102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Eight halogenated N,N'-diphenethylethylenediamines were synthesized, characterized and evaluated for σ1 receptor binding affinity in vitro. Measurements of lipophilicity also were obtained. The substitution pattern on one of the aromatic rings remained constant as 3,4-dichloro, while the substituents on the other aromatic ring were varied to include fluorine, bromine or iodine in either the 2-, 3- or 4- positions. Two main structure activity relationships were observed. First, halogen substitution on the 3- or 4-positions of the aromatic ring conferred higher binding affinities (Ki values 6.35 - 15.82 nM) than the corresponding substitutions at the 2-position (Ki values 12.08 - 43.15 nM). Second, derivatives containing either a bromo or fluoro substituent at a given position showed higher σ1 receptor binding affinities than derivatives with a corresponding iodo substituent. The data indicate that σ1 receptor affinity for this structural series is sensitive to steric bulk at the 2-position. Log k'w measurements for the halogenated N,N'-diphenethylethylenediamines were determined by high performance liquid chromatography, and varied from 2.54 - 3.71. In particular, the 3-fluoro analog exhibited a log k'w = 2.54 accompanied by a σ1 receptor Ki = 7.8 nM. These novel N,N'-diphenethylethylenediamines warrant further investigation in behavioral assays, and radiolabeled versions may prove suitable for in vivo studies of σ1 receptors.
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Affiliation(s)
- Jonathan M Fitzsimmons
- Departments of Chemistry, University of Missouri - Columbia, Columbia, MO, USA ; Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO, USA
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