The effects of serotonin (5-HT3) receptor antagonists on gastric tachyarrhythmia and the symptoms of motion sickness

Background: The purpose of this study was to determine the effects of the s erotonin (5-HT3) receptor-antagonist antiemetics ondansetron and granisetro n on the development of gastric tachyarrhythmia, nausea, and other symptoms of motion sickness. Methods: In a double-blind, counterbalanced, repeated measures design, 12 motion sickness susceptible college students participat ed in 3 sessions with an intersession interval of 1 wk. Participants receiv ed either 8 mg of ondansetron, 2 mg of granisetron, or placebo 1 h before e xposure to a rotating optokinetic drum. Electrogastrograms (EGCs) were reco rded during a 6-min baseline period and a subsequent 16-min drum rotation p eriod. Subjective symptoms of motion sickness (SSMS) were obtained every 3 min during drum rotation. Results: During drum rotation, gastric tachyarrhy thmia increased significantly more during the placebo condition than during either of the serotonin (5-HT3,) receptor antagonist conditions. However, maximum SSMS scores were not different among conditions. Conclusions: The s erotonin (5-HT3) receptor antagonists inhibited the development of tachyarr hythmia, but did not prevent the development of nausea and other symptoms o f motion sickness. The antiemetics ondansetron and granisetron may act as g astric anti-dysrhythmics, but their ability to arrest. the development of g astric tachyarrhythmia was not sufficient for the prevention of nausea.