Musk shrews selectively bred for motion sickness display increased anesthesia-induced vomiting

- Musk shrews were selectively bred (High & Low) for sensitivity to motion-induced emesis.
- Isoflurane exposure produced more emesis in High compared to Low strain animals.
- Results suggest a common mechanism for motion and inhalational anesthesia-induced emesis.

Susceptibility to motion sickness is a predictor of postoperative nausea and vomiting, and studies in humans suggest that genetic factors determine sensitivity to motion sickness. The aim of the current study was to determine if a preclinical model could be selectively bred for motion-induced emesis and to assess a potential relationship to anesthesia-induced emesis. Musk shrews were tested for motion-induced emesis using a shaker plate (10 min, 1 Hz, and 4 cm of lateral displacement). Animals were rank ordered for motion-induced emesis and selectively bred to produce high and low response strains. Shrews were also tested with nicotine (5 mg/kg, sc), copper sulfate (CuSO4; 120 mg/kg, ig), and isoflurane anesthesia (10 min; 3%) to measure responses to a panel of emetic stimuli. High response strain shrews demonstrated significantly more emetic episodes to motion exposure compared to low response strain animals in the F1 and F2 generations. In F2 animals, there were no significant differences in total emetic responses or emetic latency between strains after nicotine injection or CuSO4 gavage. However, isoflurane exposure stimulated more emesis in F1 and F2 high versus low strain animals, which suggests a relationship between vestibular- and inhalational anesthesia-induced emesis. Overall, these results indicate genetic determinants of motion sickness in a preclinical model and a potential common mechanism for motion sickness and inhalational anesthesia-induced emesis. Future work may include genetic mapping of potential “emetic sensitivity genes” to develop novel therapies or diagnostics for patients with high risk of nausea and vomiting.