The Central Reinforcing Properties of Ethanol Are Mediated by Endogenous Opioid Systems: Effects of Mu and Kappa Opioid Antagonists

Endogenous opioid systems are implicated in the reinforcing effects of ethanol and may play a substantial role in modulating the central reinforcing effects of ethanol early in ontogeny. This possibility was explored in the present study through the use of an olfactory conditioning paradigm with cen...

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Main Authors: Nizhnikov, Michael E., Varlinskaya, Elena I., Spear, Norman E.
Format: Online
Language:eng
spa
Published: Universidad Nacional de Córdoba 2009
Subjects:
Online Access:https://revistas.unc.edu.ar/index.php/racc/article/view/5299
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author Nizhnikov, Michael E.
Varlinskaya, Elena I.
Spear, Norman E.
author_facet Nizhnikov, Michael E.
Varlinskaya, Elena I.
Spear, Norman E.
author_sort Nizhnikov, Michael E.
collection Portal de Revistas
description Endogenous opioid systems are implicated in the reinforcing effects of ethanol and may play a substantial role in modulating the central reinforcing effects of ethanol early in ontogeny. This possibility was explored in the present study through the use of an olfactory conditioning paradigm with centrally administered ethanol serving as an unconditioned stimulus (US). In Experiment 1, newborn rat pups were treated with either a selective mu antagonist CTOP or kappa selective antagonist nor-BNI prior to olfactory conditioning. Experiment 2 tested the effectiveness of an alternative, shorter-duration kappa opioid antagonist GNTI in altering ethanol reinforcement. Experiment 3 investigated whether the effectiveness of pharmacological blockade of opioid receptors was due to the disruption of learning per se using an olfactory aversive conditioning paradigm with intraoral quinine serving as a US. Central administration of either mu or kappa opioid antagonists prior to conditioning disrupted the reinforcing effects of ethanol in newborn rats. The kappa opioid antagonist GNTI was as effective as nor-BNI. These effects of opioid antagonists on ethanol reinforcement are unlikely to be due to a disruption of all types of conditioning, since CTOP did not affect aversive reinforcement to intraoral infusions of quinine. The present results support the hypothesis that in newborn rats, the reinforcing properties of ethanol are mediated by the endogenous activity at mu and kappa opioid receptors.
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spelling oai:ojs.revistas.unc.edu.ar:article-52992019-05-07T17:44:12Z The Central Reinforcing Properties of Ethanol Are Mediated by Endogenous Opioid Systems: Effects of Mu and Kappa Opioid Antagonists Las propiedades de refuerzo central del etanol están mediadas por sistemas de opiáceos endógenos: efectos de los antagonistas de los opiáceos Mu y Kappa Nizhnikov, Michael E. Varlinskaya, Elena I. Spear, Norman E. infant rat opioid receptor ethanol conditioning infantil rata los receptores opiáceos etanol acondicionado Endogenous opioid systems are implicated in the reinforcing effects of ethanol and may play a substantial role in modulating the central reinforcing effects of ethanol early in ontogeny. This possibility was explored in the present study through the use of an olfactory conditioning paradigm with centrally administered ethanol serving as an unconditioned stimulus (US). In Experiment 1, newborn rat pups were treated with either a selective mu antagonist CTOP or kappa selective antagonist nor-BNI prior to olfactory conditioning. Experiment 2 tested the effectiveness of an alternative, shorter-duration kappa opioid antagonist GNTI in altering ethanol reinforcement. Experiment 3 investigated whether the effectiveness of pharmacological blockade of opioid receptors was due to the disruption of learning per se using an olfactory aversive conditioning paradigm with intraoral quinine serving as a US. Central administration of either mu or kappa opioid antagonists prior to conditioning disrupted the reinforcing effects of ethanol in newborn rats. The kappa opioid antagonist GNTI was as effective as nor-BNI. These effects of opioid antagonists on ethanol reinforcement are unlikely to be due to a disruption of all types of conditioning, since CTOP did not affect aversive reinforcement to intraoral infusions of quinine. The present results support the hypothesis that in newborn rats, the reinforcing properties of ethanol are mediated by the endogenous activity at mu and kappa opioid receptors. Los sistemas de opiáceos endógenos están implicados en los efectos reforzantes del alcohol y pueden desempeñar un papel sustancial en modular los efectos reforzantes centrales del etanol en la temprana ontogenia. El presente estudio indagó esta posibilidad a través de un paradigma de condicionamiento olfatorio en el que la administración central de etanol sirvió como estímulo incondicionado (EI). En el experimento 1, los neonatos de rata fueron pre-tratados con antagonistas selectivos para los receptores mu o kappa (CTOP y nor-BNI, respectivamente) y luego entrenados en condicionamiento olfatorio. El experimento 2 evaluó la capacidad de un antagonista kappa de corta duración (GNTI) en alterar la capacidad reforzante del etanol. El experimento 3 investigó si el bloqueo farmacológico de los receptores opiáceos podía causar una alteración inespecífica del condicionamiento olfatorio. Para ello se empleó como EI la administración intraoral de quinina. La administración central de los antagonistas opiáceos mu y kappa bloqueó los efectos reforzantes del etanol. La efectividad de GNTI fue similar a nor-BNI. Es poco probable que los efectos de antagonistas opiáceos sobre el reforzamiento al etanol sean explicados por una disrupción general de todos los tipos de condicionamiento; desde el momento en que CTOP no afecto el reforzamiento aversivo inducido por la infusión intraoral de quinina. Estos resultados respaldan la hipótesis de que las propiedades reforzantes del etanol en el neonato de rata están mediadas por la actividad endógena de los receptores opiáceos mu y kappa. Universidad Nacional de Córdoba 2009-09-02 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion application/pdf application/vnd.ms-powerpoint application/vnd.ms-powerpoint application/vnd.ms-powerpoint application/vnd.ms-powerpoint application/vnd.ms-powerpoint https://revistas.unc.edu.ar/index.php/racc/article/view/5299 10.32348/1852.4206.v1.n1.5299 Argentinean Journal of Behavioral Sciences; Vol 1, No 1 (2009): Revista Argentina de Ciencias del Comportamiento; 1-12 Revista Argentina de Ciencias del Comportamiento; Vol 1, No 1 (2009): Revista Argentina de Ciencias del Comportamiento; 1-12 1852-4206 10.32348/1852.4206.v1.n1 eng spa https://revistas.unc.edu.ar/index.php/racc/article/view/5299/5462 https://revistas.unc.edu.ar/index.php/racc/article/view/5299/24798 https://revistas.unc.edu.ar/index.php/racc/article/view/5299/24799 https://revistas.unc.edu.ar/index.php/racc/article/view/5299/24800 https://revistas.unc.edu.ar/index.php/racc/article/view/5299/24801 https://revistas.unc.edu.ar/index.php/racc/article/view/5299/24802 Derechos de autor 2009 Michael E. Nizhnikov, Elena I. Varlinskaya, Norman E. Spear
spellingShingle infant
rat
opioid receptor
ethanol
conditioning
infantil
rata
los receptores opiáceos
etanol
acondicionado
Nizhnikov, Michael E.
Varlinskaya, Elena I.
Spear, Norman E.
The Central Reinforcing Properties of Ethanol Are Mediated by Endogenous Opioid Systems: Effects of Mu and Kappa Opioid Antagonists
title The Central Reinforcing Properties of Ethanol Are Mediated by Endogenous Opioid Systems: Effects of Mu and Kappa Opioid Antagonists
title_alt Las propiedades de refuerzo central del etanol están mediadas por sistemas de opiáceos endógenos: efectos de los antagonistas de los opiáceos Mu y Kappa
title_full The Central Reinforcing Properties of Ethanol Are Mediated by Endogenous Opioid Systems: Effects of Mu and Kappa Opioid Antagonists
title_fullStr The Central Reinforcing Properties of Ethanol Are Mediated by Endogenous Opioid Systems: Effects of Mu and Kappa Opioid Antagonists
title_full_unstemmed The Central Reinforcing Properties of Ethanol Are Mediated by Endogenous Opioid Systems: Effects of Mu and Kappa Opioid Antagonists
title_short The Central Reinforcing Properties of Ethanol Are Mediated by Endogenous Opioid Systems: Effects of Mu and Kappa Opioid Antagonists
title_sort central reinforcing properties of ethanol are mediated by endogenous opioid systems effects of mu and kappa opioid antagonists
topic infant
rat
opioid receptor
ethanol
conditioning
infantil
rata
los receptores opiáceos
etanol
acondicionado
topic_facet infant
rat
opioid receptor
ethanol
conditioning
infantil
rata
los receptores opiáceos
etanol
acondicionado
url https://revistas.unc.edu.ar/index.php/racc/article/view/5299
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