Effects of chronic swim stress on EtOH-related behaviors in C57BL/6J, DBA/2J and BALB/cByJ mice

Abstract

There is a strong clinical relationship between stress and stress-related disorders and the incidence of alcohol abuse and alcoholism, and this relationship appears to be partly genetic in origin. There are marked strain differences in ethanol (EtOH)-related behaviors and reactivity to stress, but little investigation of the interaction between the two. The present study assessed the effects of chronic exposure to swim stress on EtOH-related behavior in three common inbred strains of mice, C57BL/ 6J, DBA/2J and BALB/cByJ. After establishing baseline (10%) EtOH self-administration in a twobottle free choice test, mice were exposed to daily swim stress for 14 consecutive days and EtOH consumption measured as a percent of baseline both during stress and for 10 days afterwards. A separate experiment examined the effects of 14 days of swim stress on sensitivity to the sedative/ hypnotic effects of an acute injection of 4 g/kg EtOH. Results showed that stress produced a marked and prolonged decrease in EtOH consumption in DBA/2J and BALB/cByJ, but not C57BL/6J mice. By contrast, stress increased sensitivity to the sedative/hypnotic effects of EtOH across all 3 strains. These findings demonstrate that chronic swim stress produces reductions in EtOH self-administration in a strain-dependent manner, and that these effects may be restricted to low-consuming strains. Present data also indicate a dissociation between effects of this stressor on EtOH self-administration and sensitivity to EtOH's sedative/hypnotic effects. In conclusion, strain differences, that are likely in large part genetic in nature, modify the effects of this stressor on EtOH's effects in a behaviorspecific manner. Keywords mouse; strain; ethanol; sedation; gene; drinking; swim stress; preference; two-bottle choice There is a strong epidemiological link between stress-related psychiatric disorders and alcoholism. Individuals suffering from depression or anxiety disorders, conditions often associated with stress, are more likely to abuse alcohol and become alcoholic, and tend to respond less well to therapeutic interventions [8,9,29,54]. Moreover, a history of adverse life events positively correlates with increased rates of alcoholism; although, interestingly, a proportion of individuals become abstinent following stress [19,35,46,51]. These clinic data lend support to the influential hypothesis that stress represent a significant risk factor for alcoholism [12,28]. *Corresponding author: R4N5 AP9A-L018, Abbott Laboratories, 100 Abbott Park Rd, Abbott Park, IL 60064, Ph. +1-847-937-2559, Fax +1-847-938-0072, E-mail: janel.boyce-rustay@abbott.com. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered wh...

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“…Similar controversies have been observed when employing alternative stress sources. For example, chronic 14 days of swim stress produced a significant decrease in alcohol intake in DBA/ 2J and BALB/cByJ, but not C57BL/6J mice [77]. However, restraint stress increased ethanol intake in rats [78].…”

Sex differences in the behavioral sequelae of chronic ethanol exposure

“…Ethanol drinking was assessed using a 24-hour access two-bottle choice procedure, as previously described (Boyce-Rustay, Janos, & Holmes, 2008). Ethanol-naive mice were individually housed in ‘Space Saver’ cages (Model 1145T with Model 1145T482SUDB Polysulfone cage top, Tecniplast, Buguggiate, Italy) and offered two bottles: one containing 15% (v/v) ethanol in water (unless otherwise specified) and the other containing tap water.…”

Maternal separation stress in male mice: long-term increases in alcohol intake

“…On the other hand, rats exposed to social defeat stress presented a transient suppression of alcohol intake, as well as a reduced rate of alcohol reinforcements (Van Erp and Miczek 2001). In a recent study, repeated swim stress decreased alcohol intake in mice in a strain-dependent manner (Boyce-Rustay et al 2008). …”