title: Beta-endorphin administration interferes with the acquisition and initial maintenance of ethanol preference in the rat.
abstract: Attention has been focused on the possibility of an interaction between the endorphinergic system and ethanol intake. In the present study, the effects of subcutaneous (SC) administration of beta-endorphin (beta-E) (0.25, 1 and 5 micrograms/kg) and/or naloxone (NX) (1 or 2.5 mg/kg) on ethanol preference (EP) have been investigated in rats. Under our procedural conditions, rats developed ethanol preference (EP) by a forced ethanol drinking session (conditioning session). Preconditioning administration of beta-E (1 microgram/kg) reduced later EP. When beta-E was administered postconditioning, the opioid affects ethanol preference depending on the dose: both 0.25 micrograms/kg and 5 microgram/kg reduced EP, but the dose of 1 microgram/kg did not alter it. Administration of beta-E (1 and 5 micrograms/kg) before the first testing session attenuated EP. NX antagonized the effects of beta-E on EP in the three experimental procedures used, indicating that mu-opioid receptors might be involved in the beta-E-induced reductions on EP. Our results provide further evidences for a beta-endorphinergic system involvement on the mechanism leading to consumption of ethanol.
authors.affiliation: Department of Psychobiology, Cajal Institute, Madrid, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Sandi
authors.forename: J
authors.initials: J
authors.lastname: Borrell
authors.forename: C
authors.initials: C
authors.lastname: Guaza
mesh_terms: D000428:Alcohol Drinking / Q000187:drug effects*; D000818:Animals; D001921:Brain / Q000187:drug effects; D002755:Choice Behavior / Q000187:drug effects*; D003216:Conditioning, Operant / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011957:Receptors, Opioid / Q000187:drug effects; D012153:Retention, Psychology / Q000187:drug effects; D001615:beta-Endorphin / Q000494:pharmacology*
chemical_list: D011957:Receptors, Opioid; D001615:beta-Endorphin