Long-term effects of transient chemically induced colitis on the visceromotor response to mechanical colorectal distension

Acute gastrointestinal infections with transient mucosal inflammation frequently precede the onset of functional GI disorders with altered visceral sensory function. We hypothesized that an acute inflammation of the mucosa is linked to long-lasting alterations of afferent visceral pathways. Utilizing abdominal wall electromyography, we tested the visceromotor response to tonic rectal distension (60 mm Hg/3 min) in fasted, conscious, male Lewis rats (n = 40) with a barostat device before and 2, 4, 15, and 17 weeks after rectal instillation of saline or trinitrobenzenesulfonic acid plus ethanol. Tissue samples from paired controls were obtained to assess histologic tissue alterations. Inflammatory changes were present up to 2 weeks after acid/ethanol instillation but not after saline instillation. Compared to baseline measurements, the visceromotor response to colorectal distension increased significantly and reached a maximum 17 weeks (P < 0.001) after induction of colitis, while it decreased in control experiments (P < 0.05). In conclusion, these data suggest that an acute inflammation has long-term effects on somatosensory functioning.