Animals were subjected to either the CMS protocol or the non-stress protocol (handled daily). Each day, 1–3 stressors were administered according to a set schedule. The complete regimen lasted 7 days/wk for 3 wks. This protocol is modeled after Willner (2005) in that no individual stressor is considered severe but that the unpredictability of the protocol constitutes much of the stress. The stressors were: 1) 5 min swim in 20° C water, 2) cage rotation (social stress), 3) 18-hr social isolation with damp bedding, 4) 14-hr food deprivation, 14-hr water deprivation or 14-hr food and water deprivation, 5) 30 min physical restraint, 6) 30 min strobe light exposure and 7) 3-hr cage tilt. In previous studies, we observed that this particular CMS protocol resulted in decreased body weight gain in both male and female animals and reduced sucrose preference in male animals (Reich et al., 2009). These effects are in accordance with the published behavioral effects of CMS protocols (Hill et al, 2005; Willner, 2005).
