Effects of two different acute and subchronic stressors on gastrointestinal transit in the rat: A radiographic analysis

Abstract

Background: The reaction to stress is an adaptive response necessary for survival. When stressors are repeated, the organism adapts, although these adaptive responses can become dysregulated and result in disease, causing gastrointestinal (GI) disorders. Radiographic methods allow the non- invasive study of how a given factor affects GI transit in the same animal at different time points. These methods have never been applied to study the consequences of stress on GI motor function and their depend- ency on time and stimulus. Therefore, our aim was to characterize, using radiographic techniques, the effect on GI transit of cold- restraint (CR) and forced swim (FS) stress applied acutely and subchronically in the rat. Methods: Male Wistar rats (260– 330 g) were submitted to FS or CR stress, during 1 (acute) or 4 (subchronic) consecutive days. To study GI transit, radiographic methods were used. Radiographs were taken 0– 24 h after barium intragastric administration on the 1st or 4th day of stress, which was applied 1 h after contrast. Results: Acute FS or CR slowed down gastric and small intestinal emptying but had opposite effects in the caecum: CR tended to accelerate barium transit and feces formation while FS tended to slow these parameters down. When the stimuli were applied subchronically, GI transit was not completely normalized in most of the stud- ied parameters. Conclusion and Inferences: Mild stress alters GI transit differently depending on the nature of the stressor and its duration. Exposure to mild stressors should be consid- ered as contributing factors to different functional GI disorder