Effect of autonomic nervous system manipulations on gastric myoelectrical activity and emotional responses in healthy human subjects.

OBJECTIVE: The aim of this study was to determine the gastric myoelectrical and emotional responses provoked by two psychophysiological stimuli known to cause in one case increased sympathetic nervous system activity and in the other increased parasympathetic nervous system activity.
METHODS: Electrogastrograms (EGGs) were recorded, and interbeat intervals (IBIs) were obtained from electrocardiographic recordings from 20 subjects during baseline and in response to a shock avoidance task (shock stimulus) and forehead cooling (dive stimulus). After each experimental period, subjects reported their emotional experience by rating descriptors ranging from serenity to excitement.
RESULTS: During the shock stimulus, IBIs decreased significantly (p < .05), gastric tachyarrhythmias increased (p < .05), and emotional arousal increased, as indexed by reports of increased interest, excitement, and activation. In contrast, during the dive stimulus, IBIs increased (p < .05), but there were no associated changes in gastric myoelectrical activity or emotional arousal.
CONCLUSIONS: Acute stress can evoke arousal and dysrhythmic gastric myoelectrical activity, and these acute changes, which occur in healthy individuals, may provide insight into functional gastrointestinal disorders.