Biological Contribution to Social Influences on Alcohol Drinking: Evidence from Animal Models

Abstract

Social factors have a tremendous influence on instances of heavy drinking and in turn impact public health. However, it is extremely difficult to assess whether this influence is only a cultural phenomenon or has biological underpinnings. Research in non-human primates demonstrates that the way individuals are brought up during early development affects their future predisposition for heavy drinking, and research in rats demonstrates that social isolation, crowding or low social ranking can lead to increased alcohol intake, while social defeat can decrease drinking. Neurotransmitter mechanisms contributing to these effects (i.e., serotonin, GABA, dopamine) have begun to be elucidated. However, these studies do not exclude the possibility that social effects on drinking occur through generalized stress responses to negative social environments. Alcohol intake can also be elevated in positive social situations, for example, in rats following an interaction with an intoxicated peer. Recent studies have also begun to adapt a new rodent species, the prairie vole, to study the role of social environment in alcohol drinking. Prairie voles demonstrate a high degree of social affiliation between individuals, and many of the neurochemical mechanisms involved in regulation of these social behaviors (for example, dopamine, central vasopressin and the corticotropin releasing factor system) are also known to be involved in regulation of alcohol intake. Naltrexone, an opioid receptor antagonist approved as a pharmacotherapy for alcoholic patients, has recently been shown to decrease both partner preference and alcohol preference in voles. These findings strongly suggest that mechanisms by which social factors influence drinking have biological roots, and can be studied using rapidly developing new animal models.

Activation of μ-Opioid Receptors in the Dorsal Striatum is Necessary for Adult Social Attachment in Monogamous Prairie Voles

“…The CP represents an anatomically and physiologically parallel region of striatum that has not previously been implicated in partner preference formation. The involvement of the opiate system in the formation of adult social attachments is of particular importance as opioid antagonists, including NTX, are being used increasingly in humans as a treatment for alcoholism, opioid dependence, obesity, and fibromyalgia (Ablin and Buskila, 2010;Anacker and Ryabinin, 2010;Greenway et al, 2010;Lobmaier et al, 2010;Soyka and Rosner, 2010). Furthermore, the role of MOR in this behavior provides a vital link between the pair bonding literature and previous literature on maternal behavior, which further supports the hypothesis that the pair bonding circuitry evolved from the same mechanisms governing maternal behavior that are present in all mammals (Donaldson and Young, 2008).…”

Translational Models of Interactions Between Stress and Alcohol Consumption: Strengths and Limitations

“…In some cases, acute exposure to stressors such as footshock, cold water swim, or brief restraint increase alcohol intake (Fullgrabe et al 2007;Lynch et al 1999;Siegmund et al 2005;), whereas other studies fi nd no effect or even a negative effect of stress on alcohol intake. For example, studies have reported that single or repeated restraint stress or footshock had no effect on alcohol intake (Bowers et al 1997;Funk et al 2004;Tambour et al 2008), or that a reduction in alcohol intake was produced by social defeat stress (Anacker and Ryabinin 2010;Funk et al 2004;van Erp and Miczek 2001), novelty-related stress (Sabino et al 2006), restraint stress (Chester et al 2004;Rockman and Glavin 1986), or cold water swim (BoyceRustay et al 2008). Resolving these mixed results is challenging, as there are many potential differences, such as type of stressor, species or strain of rat or mouse, and paradigm of alcohol exposure, as evidenced in the following examples.…”

“…Research has demonstrated the importance of social support for the prevention and treatment of alcoholism in humans (Anacker and Ryabinin 2010;Brown et al 1995;Fulkerson et al 2006;Killgore et al 2008;Noone et al 1999;Pohorecky 1991;Wang et al 2009). Animal models may reveal much about basic aspects of the neural circuitry through which positive and negative social interactions regulate alcohol addiction.…”

“…Animal models may reveal much about basic aspects of the neural circuitry through which positive and negative social interactions regulate alcohol addiction. Rodent and primate studies have shown that social interaction can buffer stress-related development of addiction and, conversely, that social isolation enhances alcohol intake (Anacker and Ryabinin 2010;Roske et al 1994;Wolffgramm and Heyne 1991).…”

The Effects of Proximal and Distal Social Stimulation on Ethanol Intake in Male and Female CD-1 Mice

“…The stimulating effects of direct proximal social interactions on ethanol intake have also been reported in a number of rodent species, including rats [6,7,8,9,10,11,12,13], mice [14,15,16], and prairie voles [17,18]. It should be noted that several early investigations employing animal subjects evaluated the effects of social stimulation by comparing ethanol consumption in isolation-housed versus group-housed rodents, and found little evidence of social stimulation of ethanol drinking [7,8,16,19,20].…”