Stereotaxic delivery of corticosterone to the amygdala modulates colonic sensitivity in rats

Episodes of anxiety are often associated with the onset or exacerbation of visceral pain in patients with irritable bowel syndrome (IBS). The central amygdaloid nucleus (CeA) is a key limbic structure involved in the expressi on of anxiety as well as a major site for regulating autonomic and visceral responses to stress. Previous experiments have shown that glucocorticoids can act directly at the CeA to increase the level of anxiety in rats. There fore, the goal of this study was to examine the effect of stereotaxic deliv ery of corticosterone into the CeA on the development of visceral hypersens itivity by measuring visceromotor response to colorectal distention in rats . Stereotaxic delivery of corticosterone to the CeA increases indices of an xiety and produces a hypersensitive colon as demonstrated by an exaggerated visceromotor response to colorectal distention in the F344 rat strain. Our findings suggest that modulation of anxiety by manipulating amygdala funct ion with corticosterone induced colonic hypersensitivity via descending neu ronal pathways from the CeA. (C) 2001 Elsevier Science B.V. All rights rese rved.