Ethanol condition place aversion in [beta]-endorphin deficient mice. (South Carolina Academy of Sciences Abstracts).
Ethanol (EtOH) is postulated to produce at least some of its pleasurable effects through interaction with the endogenous opioid system. Differences in basal or EtOH-induced activation of the opioid system are thought to contribute to abuse liability. Both human and animal studies have found a relationship between levels of the opioid peptide [beta]-endorphin and EtOH response. This study utilized a conditioned place preference (CPP) paradigm to investigate pleasurable and aversive effects of EtOH in mice that differed with respect to [beta]-endorphin. Naive, adult, male and female [beta]-endorphin knockout, heterozygotes, and wildtype (C57B1/6J) mice were conditioned to a 3-chambered CPP apparatus with EtOH on one side and saline on the other side for four consecutive days. Two conditional sessions separated by five hours took place each day. Each mouse was injected intraperitoneally with either 1.0 g/kg EtOH or saline and placed into one side of the CPP apparatus for ten minutes. Each side was paired with either a pine or spruce scent and a distinguishably textured floor, each counterbalanced across sex and genotype. On the fifty day, side preference was tested for ten minutes following saline injection. Knockouts, but not heterozygotes or wildtypes, demonstrated a significant aversion to the EtOH-paired compartment. However, a two-factor ANOVA showed a significant interaction between strain and sex, suggesting that a lack of [beta]-endorphin has different effects in male and female mice. Male knockouts but not heterozygotes, avoid the EtOH-paired chamber. Side preference in females does not appear to be dependent upon [beta]-endorphin levels.
Lori Elizabeth Jones, Judith E. Grisel Department of Psychology Furman University
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|Title Annotation:||psychology research|
|Author:||Jones, Lori Elizabeth; Grisel, Judith E.|
|Publication:||Bulletin of the South Carolina Academy of Science|
|Article Type:||Brief Article|
|Date:||Jan 1, 2003|
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