Suppressive mechanism of gastric motility by whole-body vibration

Objective: To investigate the mechanism of gastric motility suppression by exposure to whole-body vibration (WBV). Methods: The gastric motility was e valuated by electrogastrography (EGG) under food intake and autonomic nerve blocking agents in ten healthy volunteers. Sinusoidal vertical vibration w ith a frequency of 4 Hz (1.0 ms(-2) rms) was given to the subject for 10 mi n. Results: The amplitude of EGG wave and the power spectrum corresponding to the slow wave component was remarkably decreased by vibration exposure. Food intake enhanced the gastric motility about 2.5-fold in the power spect ral density. During and after vibration exposure, the response mode was sim ilar to those at fasting states. Under the influence of anticholinergic (sc opolamine) and alpha-adrenergic blocking agents (prazosin), the power spect ra were decreased. A further decrease was observed during vibration exposur e. A beta-adrenergic blocking agent (propranolol) led to a marked increase in the amplitude of EGG and its power spectrum. With pretreatment by a beta -adrenergic blocking agent, however, vibration exposure reduced both of the m. Conclusions: These results suggest that short-term exposure to WBV can s uppress the gastric myoelectric activity, the responses on which may be med iating by neurohumoral effects as well as the mechanical effect of WBV.