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Navarro M, Carvajal F, Lerma-Cabrera JM, Cubero I, Picker MJ, Thiele TE. Evidence that Melanocortin Receptor Agonist Melanotan-II Synergistically Augments the Ability of Naltrexone to Blunt Binge-Like Ethanol Intake in Male C57BL/6J Mice. Alcohol Clin Exp Res 2015; 39:1425-33. [PMID: 26108334 DOI: 10.1111/acer.12774] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2014] [Accepted: 05/02/2015] [Indexed: 12/11/2022]
Abstract
BACKGROUND The nonselective opioid receptor antagonist, naltrexone (NAL), reduces alcohol (ethanol [EtOH]) consumption in animals and humans and is an approved medication for treating alcohol abuse disorders. Proopiomelanocortin (POMC)-derived melanocortin (MC) and opioid peptides are produced in the same neurons in the brain, and recent preclinical evidence shows that MC receptor (MCR) agonists reduce excessive EtOH drinking in animal models. Interestingly, there is a growing body of literature revealing interactions between the MC and the opioid systems in the modulation of pain, drug tolerance, and food intake. METHODS In the present report, a mouse model of binge EtOH drinking was employed to determine whether the MCR agonist, melanotan-II (MTII), would improve the effectiveness of NAL in reducing excessive binge-like EtOH drinking when these drugs were co-administered prior to EtOH access. RESULTS Both NAL and MTII blunt binge-like EtOH drinking and associated blood EtOH levels, and when administered together, a low dose of MTII (0.26 mg/kg) produces a 7.6-fold increase in the effectiveness of NAL in reducing binge-like EtOH drinking. Using isobolographic analysis, it is demonstrated that MTII increases the effectiveness of NAL in a synergistic manner. CONCLUSIONS The current observations suggest that activators of MC signaling may represent a new approach to treating alcohol abuse disorders and a way to potentially improve existing NAL-based therapies.
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Affiliation(s)
- Montserrat Navarro
- Department of Psychology, University of North Carolina, Chapel Hill, North Carolina
| | | | | | | | - Mitchell J Picker
- Department of Psychology, University of North Carolina, Chapel Hill, North Carolina
| | - Todd E Thiele
- Department of Psychology, University of North Carolina, Chapel Hill, North Carolina.,Bowles Center for Alcohol Studies, University of North Carolina, Chapel Hill, North Carolina
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Juárez J, Barrios De Tomasi E. Naltrexone treatment produces dose-related effects on food and water intake but daily alcohol consumption is not affected. Nutr Neurosci 2013; 11:183-92. [DOI: 10.1179/147683008x301577] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Yang HD, Wang Q, Wang Z, Wang DH. Food hoarding and associated neuronal activation in brain reward circuitry in Mongolian gerbils. Physiol Behav 2011; 104:429-36. [PMID: 21570992 DOI: 10.1016/j.physbeh.2011.04.062] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Revised: 04/17/2011] [Accepted: 04/28/2011] [Indexed: 11/18/2022]
Abstract
Mongolian gerbils (Meriones unguiculatus) display food hoarding and thus provide an opportunity to study the neuromechanisms underlying this behavior. In the present study, male gerbils exhibited a bimodal expression of food hoarding behavior-some displayed high levels of food hoarding whereas others virtually lacked this behavior under normal laboratory conditions with free access to food. Food hoarding was found to be associated with an increase in neuronal activation, indicated by Fos immunoreactive (ir) staining, in several brain areas including the nucleus accumbens, ventral tegmental area (VTA), and lateral hypothalamus. Food hoarding was also associated with increases in the number of cells labeled for tyrosine hydroxylase (TH-ir), the rate limiting enzyme for dopamine conversion, and the number of cells co-labeled for TH-ir/Fos-ir in the VTA, suggesting that dopamine in the brain reward circuitry may be involved in food hoarding. Further, we found that 22 h of food deprivation induced food hoarding in some, but not all, males that naturally did not display food hoarding. In these males, however, food hoarding did not increase TH-ir or TH-ir/Fos-ir expression in the VTA. Together, these data indicate that male Mongolian gerbils display diverse phenotypes of food hoarding behavior and that dopamine in the brain reward circuitry may be involved in the control of naturally occurring, but not food deprivation-induced, food hoarding.
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Affiliation(s)
- Hui-Di Yang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
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Differential effects of chronic naltrexone treatment on food intake patterns and body weight in rats depend on their food deprivation status. Eur J Pharmacol 2011; 650:261-7. [DOI: 10.1016/j.ejphar.2010.10.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Revised: 09/23/2010] [Accepted: 10/06/2010] [Indexed: 11/17/2022]
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Measurement of naltrexone in rat brain regions and serum by high performance liquid chromatography with electrochemical detection. Chromatographia 1988. [DOI: 10.1007/bf02259022] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Kavaliers M, Innes D. Stress-induced opioid analgesia and activity in deer mice: sex and population differences. Brain Res 1987; 425:49-56. [PMID: 3427425 DOI: 10.1016/0006-8993(87)90482-3] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
We compared restraint stress-induced opioid, analgesic and locomotory responses of 4 different populations of male and female deer mice, Peromyscus maniculatus artemisiae and P. m. nebrascensis from mainlands, and P. m. angustus and P. m. triangularis from small islands. All of the deer mice displayed immobilization-induced analgesia which was blocked by the prototypical mu-opiate antagonist, naloxone (1.0 mg/kg). In all of the populations males displayed significantly greater levels of analgesia than females. In addition, the levels of opioid-induced analgesia were significantly greater in the insular than in the mainland male and female deer mice. Restraint also induced significant increases in the locomotor activity of the mainland deer mice, while significantly decreasing the activity of the insular animals. Males displayed significantly greater stress-induced changes in locomotor activity than did females. The stress-induced increases in activity were blocked by the delta-opiate antagonist, ICI 154, 129 (10 mg/kg), while the decreases in activity were inhibited by naloxone. These results demonstrate that there are marked sex and population differences in the stress-induced, opioid-mediated responses of deer mice. These 'pharmaco-ecological' findings also suggest that the island-mainland population differences in behavioral responses and ecological characteristics may, in part, be related to differences in the activity of mu-, delta- and possibly other opioid systems.
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Affiliation(s)
- M Kavaliers
- Division of Oral Biology, Faculty of Dentistry, The University of Western Ontario, London, Canada
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Kavaliers M, Innes DG. Sex and day-night differences in opiate-induced responses of insular wild deer mice, Peromyscus maniculatus triangularis. Pharmacol Biochem Behav 1987; 27:477-82. [PMID: 3659070 DOI: 10.1016/0091-3057(87)90351-0] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
We examined the effects of mu and kappa opiate agonists on the day- and night-time nociceptive, locomotory and ingestive behaviors of an island population of wild male and female deer mice, Peromyscus maniculatus triangularis. The prototypical mu opiate agonist, morphine, had significant analgesic and locomotory effects, which were blocked by naloxone, and the specific delta opiate antagonist, ICI 154,129, respectively. The specific kappa opiate agonist, U-50,488, had significant analgesic actions and inhibitory effects on locomotor activity, as well as stimulating feeding. Significant day-night variations occurred in the analgesic and activity responses, with the mu and kappa opiate agonists having significantly greater effects at night. There were also prominent sex differences in responses; male deer mice displaying significantly greater levels of mu and kappa opiate-induced analgesia and alterations in activity than female animals. These sex differences in opiate-induced effects were most pronounced at night, female deer mice displaying reduced day-night rhythms of responsiveness. These results demonstrate the existence of significant day-night rhythms and sex differences in the mu and kappa opiate behavioral responses of a wild population of rodents.
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Affiliation(s)
- M Kavaliers
- Division of Oral Biology, Faculty of Dentistry, University of Western Ontario, London, Canada
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Kavaliers M, Innes DG. Sex differences in magnetic field inhibition of morphine-induced responses of wild deer mice, Peromyscus maniculatus triangularis. Physiol Behav 1987; 40:559-62. [PMID: 3671517 DOI: 10.1016/0031-9384(87)90096-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
An exposure for 60 min to a 0.5 Hz weak rotating magnetic field (1.5-90 G) reduced the day-time locomotory and analgesic effects of morphine (10 mg/kg) in a wild population of deer mice. Peromyscus maniculatus triangularis. Females displayed significantly lower levels of morphine-induced responses and sensitivity to the inhibitory effects of the magnetic fields than did the males. These responses indicate that there are sex differences in the effects of weak magnetic fields on the opiate-mediated responses of a wild rodent, with males being more responsive to the magnetic stimuli than females.
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Affiliation(s)
- M Kavaliers
- Division of Oral Biology, Faculty of Dentistry, University of Western Ontario, London, Canada
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Kavaliers M, Hirst M. Food hoarding and ingestion in the deer mouse, Peromyscus maniculatus: selective responses to mu and kappa opiate agonists. Pharmacol Biochem Behav 1986; 25:543-8. [PMID: 3022306 DOI: 10.1016/0091-3057(86)90138-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The feeding behavior of the deer mouse, Peromyscus maniculatus, includes food hoarding as well as ingestion. Administration of the prototypical mu opiate agonist, morphine sulfate, 1-20 mg/kg, produced over three hours a significant dose-dependent stimulation of hoarding by free feeding deer mice. The specific kappa opiate agonist, U-50,488H, 0.10-10 mg/kg, markedly increased ingestion without having any augmentatory effects on hoarding. The mixed mu and kappa opiate agonist, ketocyclazocine hydrochloride, 1-10 mg/kg, as well as various combinations of morphine sulfate and U-50,488H, augmented both hoarding and ingestion. Food restriction for 24 hr caused a significant, naloxone (1.0 mg/kg) reversible, increase in food intake. Food deprivation also modified the hoarding and ingestion responses of the deer mice to the mu and kappa opiate agonists, reducing the relative amounts of food that were hoarded. These results indicate that mu and kappa opioid systems are differentially involved in the mediation of various aspects of feeding. This also suggests that environmental factors, such as food restriction, can modify the relative roles of mu and kappa opioid systems in the expression of feeding behavior.
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Kavaliers M, Hirst M. Differential opiate influences on food hoarding and intake in the deer mouse, Peromyscus maniculatus. Life Sci 1985; 37:2213-20. [PMID: 2999543 DOI: 10.1016/0024-3205(85)90574-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The feeding behavior of the deer mouse, Peromyscus maniculatus, includes food hoarding as well as ingestion. In this animal the mu opiate agonist, morphine, and the kappa opiate agonist, U-50, 488H, selectively stimulate food hoarding and ingestion, respectively. This suggests that mu and kappa opiate systems may differentially mediate primary components of natural feeding behavior.
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Abstract
This paper is the seventh in an annual series of reviews of research involving the endogenous opiate peptides, each installment being restricted to work published during the previous year. As in the past three years, the review this year is limited to non-analgesic and behavioral studies of the opiate peptides. The specific topics this year include: stress, tolerance and dependence, consummatory responses, gastric and renal activity, alcohol, mental illness, learning and memory, cardiovascular responses, respiratory effects, thermoregulation, seizures and neurological disorders, activity, and miscellaneous other topics.
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Abstract
The increased spontaneous locomotor activity (SLMA) of rats exposed to a novel environment is decreased by opiate antagonists. In the present study, naltrexone (1.0-40 mg/kg) failed to reduce the SLMA of hamsters exposed to the novel environment of activity cages. The SLMA of another group of untreated hamsters declined following 4 consecutive exposures to the activity cages. Thus, the novelty-induced increase in hamster SLMA is not sensitive to opiate antagonism. The differential sensitivity of rats and hamsters to opiate effects on activity and feeding may be due to the presence of an opiate-sensitive hibernation system in hamsters.
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