Brain Fos expression and intestinal motor alterations during nematode-induced inflammation in the rat

Brain-gut interactions and intestinal motility were studied during pulmonary and jejunal inflammation induced by Nippostrongylus brasiliensis. Jejunal electromyographic activity was continuously recorded from day 1 before to day 28 after infection. Expression of c-fos was assessed in the brain by immunohistochemistry, and myeloperoxidase (MPO) activity was determined in lung and intestine on days 1,7,14, 21, and 28 postinfection. The cyclic intestinal motor pattern was replaced by an irregular activity from day 4, corresponding to larvae migration to the intestine, to day 14. c-fos was expressed in the caudal nucleus of the solitary tract (NTS) and lateral parabrachial nucleus (LPB) on day 1 (lung stage of N. brasiliensis) and in the medial part of the NTS, the LPB, and locus ceruleus on day 7. Pulmonary and intestinal MPO activity was increased from days 1 to 21 postinfection. During N. brasiliensis infection, c-fos expression indicates that specific and different brain nuclei are activated at the onset of pulmonary and intestinal inflammation, which is associated with motor disorders.