Suncus murinus as a new experimental model for motion sickness

Characteristics of motion sickness and effects of possible prophylactic drugs were studied using Suncus murinus (house musk shrew) for its potential use as an experimental model in motion sickness. Mild reciprocal shaking (amplitude: 10-40 mm; frequency: 0.5-3.0 Hz) induced vomiting in most of Suncus murinus within 2 min. Adaptation was observed when the motion stimulus was repeated with an interval of 2 to 3 days. During the repetitive motion training, both the ratio of sensitive animals and the number of vomiting episodes decreased, and the time from the start of shaking to the first vomiting was extended. Subcutaneous injection of scopolamine (100 mg/kg), chlorpromazine (8 mg/kg), promethazine (50 mg/kg), diphenhydramine (20 mg/kg), chlorphenylamine (20 mg/kg) and methamphetamine (2 mg/kg) decreased the emetic effect of motion sickness, but pyrilamine (20 mg/kg), meclizine (20 mg/kg) and dimenhydrinate (32 mg/kg) were not effective or very weak. These results indicate that the Suncus murinus is sensitive to the motion stimulus and antiemetic drugs are effective as prophylaxis. The Suncus murinus is useful as a new experimental animal model for motion sickness.