Date

11-1-2012

Document Type

Dissertation

Degree Name

Ph.D.

Department

Dept. of Behavioral Neuroscience

Institution

Oregon Health & Science University

Abstract

Alcohol use disorders are a prevalent problem that can lead to harmful effects on an individuals health, functioning, and social relationships. Social interactions can in turn affect alcohol intake. It is important to study these behavioral interactions, and in particular the biological underpinnings of these behaviors, in order to understand how they influence alcohol use disorders, and how these disorders may be prevented or treated. Animal models of human disease can be particularly useful for studying the biological bases of related mechanisms and behaviors, and for testing potential treatments. However, until now, an adequate laboratory animal model of the interactions between alcohol drinking and specific adult social attachments did not exist. Thus, the aim of this dissertation was to establish a novel animal model of the interactions between social relationships and alcohol drinking. To accomplish this goal, prairie voles (Microtus ochrogaster) were used to model these behavioral interactions. Prairie voles are socially monogamous and readily form strong, lasting bonds between specific individuals, unlike traditional laboratory rodents. Also unlike most other animals, prairie voles show a natural high preference for unsweetened alcohol, as demonstrated here. These features combined make prairie voles an ideal model for examining the interactions between social bonds and alcohol drinking. Here we find that prairie voles show a higher preference for alcohol when they are housed in pairs with siblings or peers, rather than housed in isolation, and they match each other??s alcohol intake. This models the social facilitation of alcohol drinking often observed in humans. Furthermore, when a high-drinking prairie vole is paired with a low drinker, the high drinker usually decreases its alcohol intake, demonstrating a direct peer influence to decrease drinking. Susceptibility to peer influence may be predicted by individual variation in features of drinking behavior, but not by voles changing drinking patterns to drink together. A genetic polymorphism known to play a role in prairie vole social behaviors did not predict the susceptibility to alter drinking when influenced by a peer. The procedures established in the experiments described here allow us to model the important role of social influences, particularly to decrease problem drinking. In another set of experiments we tested the effects of alcohol on pair bond formation in adult prairie voles. We found that the effects were opposite for males and females: alcohol drinking during the bond formation period facilitated a preference for the partner in female prairie voles but inhibited it in males. We explored a number of possible neurobiological mechanisms behind these effects and found support for the role of several neuropeptides known to be involved in stress, anxiety, and response to alcohol. With these experiments, we establish that prairie voles can model a number of human behaviors relevant to interactions between social relationships and alcohol drinking: social facilitation of alcohol drinking, peer influence to decrease drinking, and alcohol acting to facilitate or inhibit formation of social bonds. Future studies of these behaviors and underlying neurobiological mechanisms will allow us to gain a better understanding of causes, influences, and treatment strategies that can help people with alcohol use disorders.

Identifier

doi:10.6083/M4J67DZ1

School

School of Medicine

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