Effects of systemic opioid receptor ligands on ethanol- and sucrose seeking and drinking in alcohol-preferring (P) and Long Evans rats

Angela Henderson-Redmond, Cristine Czachowski

Research output: Contribution to journalArticle

28 Scopus citations

Abstract

The endogenous opioid system has been implicated in mediating the reinforcing effects of ethanol (EtOH). Naltrexone (NTX), an opioid antagonist with concentration-dependent selectivity for the mu receptor, naltrindole (NTI), a selective delta receptor antagonist, and U50,488H, a selective kappa receptor agonist were examined in both alcohol-preferring (P) and nonselected (Long Evans (LE)) rats to determine whether they differentially affected the seeking and consumption of EtOH and sucrose. Using the sipper-tube model, rats reinforced with either 2 % sucrose or 10 % EtOH were injected with vehicle and either NTI (2.5, 5.0, or 10.0 mg/kg), U50 (2.5, 5.0, or 10.0 mg/kg), low-dose NTX (0.1, 0.3, or 1.0 mg/kg), or high-dose NTX (1.0, 3.0, or 10.0 mg/kg). Subsequent intakes (consummatory) or lever responses (seeking) were assessed. Overall, NTI, U50, and NTX attenuated intake and responding for sucrose and EtOH, with EtOH-reinforced P rats being the most sensitive to the effects of NTI on intake and seeking. U50 treatment decreased intake and seeking in both P and LE rats but did not selectively reduce EtOH intake or seeking in either line. P rats were more sensitive than LE rats to lower doses of NTX, and these doses more selectively attenuated responding for EtOH than sucrose. Higher doses of NTX suppressed intake and responding across both lines and reinforcers. These results suggest that drugs selective for the opioid receptors may be good pharmacotherapeutic targets, particularly in those with an underlying genetic predisposition for greater EtOH preference/intake.

Original languageEnglish (US)
Pages (from-to)4309-4321
Number of pages13
JournalPsychopharmacology
Volume231
Issue number22
DOIs
StatePublished - Nov 2014

Keywords

  • Alcohol
  • Motivation
  • Naltrexone
  • Naltrindole
  • Opioid receptor
  • Reinforcement
  • Self-administration
  • U50,488H

ASJC Scopus subject areas

  • Pharmacology

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