Sucrose Preference Test to Measure Stress-induced Anhedonia

The 2-bottle choice procedure for assessing sucrose preference is a useful test to investigate anhedonia (i.e., inability to feel pleasure) in laboratory rodents, particularly in stress-based models of depression. The 2-bottle choice procedure allows for a comparison between behavioral preference for sucrose solution in drinking water compared to water only. Preference is measured by volume and/or weight of liquid consumed daily, which is then converted to a percent preference compared to a water only baseline period. Sucrose preference is attenuated by a diversity of chronic stressors, including chronic mild and unpredictable stress (Willner et al., 1992; Willner, 1997; Pothion et al., 2004) and social defeat stress (Krishnan et al., 2007). It may also be susceptible to perturbation in mouse models of drug addiction because sucrose preference is altered in drug-dependent individuals (Kampov-Polevoy et al., 1997; Bogucka-Bonikowska et al., 2002; Janowsky et al., 2003). Both stress- and drug-induced alterations in sucrose preference may stem from maladaptations in the reward pathway, which consists of the dopaminergic neurons extending from the ventral tegmental area to the nucleus accumbens (NAc). Indeed, alterations in cyclic-AMP response element binding protein (CREB) activity in NAc underlie preference for sucrose (Barrot et al., 2002). Additionally, the transcription factor ΔFosB in NAc (Wallace et al., 2008), but not dorsal hippocampus (Eagle et al., 2015), regulates natural rewards, such as sucrose consumption. Therefore, the sucrose preference test described below provides a well-validated model to assess anhedonia and the function of specific brain regions and circuits.