Meal patterns and hypothalamic gene expression following chronic social stress

In the visible burrow system (VBS) model of chronic social stress male rats are housed with females resulting in a dominance hierarchy with one dominant (DOM) and three subordinate (SUB) males. Previous work has described behavioral, physiological and neuroendocrine changes during VBS stress and subsequent recovery. Specifically, SUB animals display several signs of severe stress exposure including thymic involution, adrenal hypertrophy, increased basal corticosterone, and dramatic decreases in body weight. This loss of body weight is concomitant with metabolic consequences such as changes in glucose tolerance and altered food intake strategies. SUB animals consume less food in smaller, shorter meals compared to DOM while housed in the VBS. Prior studies have examined neuropeptides known to affect food intake and found increased neuropeptide Y (NPY) expression in the dorsomedial hypothalamus of SUB animals following stress. Elevated NPY is predictive of increased meal size, but not meal number. Although, SUB animals are hyperphagic in their initial recovery from stress, it is unknown if the increased NPY expression observed in these animals is associated with altered patterns of ingestion. The current study will examine meal patterns and hypothalamic gene expression after VBS stress, 3 days of recovery, and 3 weeks of recovery. Supported by: DK066596.