Consequences of intestinal inflammation on the enteric nervous system: Neuronal activation induced by inflammatory mediators

The ENS is responsible for the regulation and control of all gastrointestin al functions. Because of this critical role, and probably as a consequence of its remarkable plasticity, the ENS is often relatively well preserved in conditions where the architecture of the intestine is seriously disrupted, such as in IBD. There are structural and functional changes in the enteric innervation in animal models of experimental intestinal inflammation and i n IBD. These include both up and down regulation of transmitter expression and the induction of new genes in enteric neurons. Using Fos expression as a surrogate marker of neuronal activation it is now well established that e nteric neurons (and also enteric glia) respond to inflammation. Whether thi s "activation" is limited to a short-term functional response, such as incr eased neuronal excitability, or reflects a long-term change in some aspect of the neuronal phenotype (or both) has yet to be firmly established, but i t appears that enteric neurons are highly plastic in their response to infl ammation. Anat Rec 262:79-90, 2001. a 2001 Wiley-Liss, Inc.