Stress and gastrointestinal motility in animals: a review of the literature

In the last decade an increasing number of studies have been published dealing with the effects of experimental stress on gastrointestinal functions in animals and humans. Initial interest in gastrointestinal stress responses in the late 1940s and early 1950s¹ was followed by continued interest only in experimental ulcer research.² The recent ‘revival’ of interest in stress is due to some methodological progress: first, our understanding of gastrointestinal functions, specifically gastrointestinal motility has grown after new measurement techniques became widely available to enable gastrointestinal stress effects to be determined directly-instead of its indirect outcome such as stool frequency or gastrointestinal symptoms. Second, interest has grown in functional abdominal disorders such as the irritable bowel syndrome or non-ulcer dyspepsia, which are often believed to be, at least in part, stress related.³ Finally, stress has become a major paradigm by which to investigate brain-gut interactions, specifically with respect to the yet unanswered question of the extent of autonomy or CNS control to regulate gastrointestinal functions.⁴ Our review is split into two parts. The first part focused on clinical aspects in human studies.¹ This part will deal with animal studies and discusses their relevance with respect to basic research questions.