A L Sharpe 1, H H Samson. 1. Department of Physiology and Pharmacology, Center for the Neurobehavioral Study of Alcohol, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157-1083, USA. asharpe@wfubmc.edu
Abstract
BACKGROUND: The opioid system has been implicated in ethanol self-administration. Morphine, an opiate agonist, can sometimes increase the amount of ethanol consumed, and opiate antagonists such as naloxone and naltrexone decrease the amount of ethanol consumed in both animals and humans. The objective of this study was to examine the effect of naloxone on appetitive (or seeking) and consummatory behaviors by using an operant model developed to separate these two phases of self-administration. METHODS: Intraperitoneal injections of naloxone (0.3-10 mg/kg) or vehicle were given before operant self-administration sessions to assess the effect on lever pressing (appetitive behavior) and subsequent consumption. Effects were measured in two groups of rats: one self-administered a 3% sucrose solution and the other a 10% ethanol solution. RESULTS: Naloxone dose-dependently decreased ethanol and sucrose consumption by an earlier cessation of drinking in the session compared with vehicle injection days. There were some effects on appetitive responding after treatment with naloxone, but none was statistically significant. CONCLUSIONS: Naloxone may decrease ethanol self-administration by decreasing the postingestive or pharmacological effects of alcohol. This model provides a new method for examining the effects of potential pharmacotherapeutics on alcohol self-administration behavior.
BACKGROUND: The opioid system has been implicated in ethanol self-administration. Morphine, an opiate agonist, can sometimes increase the amount of ethanol consumed, and opiate antagonists such as naloxone and naltrexone decrease the amount of ethanol consumed in both animals and humans. The objective of this study was to examine the effect of naloxone on appetitive (or seeking) and consummatory behaviors by using an operant model developed to separate these two phases of self-administration. METHODS: Intraperitoneal injections of naloxone (0.3-10 mg/kg) or vehicle were given before operant self-administration sessions to assess the effect on lever pressing (appetitive behavior) and subsequent consumption. Effects were measured in two groups of rats: one self-administered a 3% sucrose solution and the other a 10% ethanol solution. RESULTS:Naloxone dose-dependently decreased ethanol and sucrose consumption by an earlier cessation of drinking in the session compared with vehicle injection days. There were some effects on appetitive responding after treatment with naloxone, but none was statistically significant. CONCLUSIONS:Naloxone may decrease ethanol self-administration by decreasing the postingestive or pharmacological effects of alcohol. This model provides a new method for examining the effects of potential pharmacotherapeutics on alcohol self-administration behavior.
Authors: Shkelzen Shabani; Lauren K Dobbs; Matthew M Ford; Gregory P Mark; Deborah A Finn; Tamara J Phillips Journal: Neuropharmacology Date: 2012-01-20 Impact factor: 5.250
Authors: Roberto Sebastián Miranda-Morales; Juan Carlos Molina; Norman E Spear; Paula Abate Journal: Psychopharmacology (Berl) Date: 2011-07-13 Impact factor: 4.530
Authors: Raúl Pastor; Laura Font; Marta Miquel; Tamara J Phillips; Carlos M G Aragon Journal: Alcohol Clin Exp Res Date: 2011-10-20 Impact factor: 3.455
Authors: Matthew M Ford; Gregory P Mark; Jeffrey D Nickel; Tamara J Phillips; Deborah A Finn Journal: Behav Brain Res Date: 2007-02-23 Impact factor: 3.332
Authors: Raymond F Anton; David J Drobes; Konstantin Voronin; Ramon Durazo-Avizu; Darlene Moak Journal: Psychopharmacology (Berl) Date: 2004-01-14 Impact factor: 4.530