Experimental Motion Sickness in Dogs

Abstract
Motion sickness was experimentally induced in dogs by means of a standardized swinging exposure. Susceptible dogs were selected for surgical extirpation of the labyrinths or various parts of the cerebellum. It was found that animals showed no vomiting responses to long exposures of swinging motion after bilateral labyrinthectomy or ablation of the nodulus and uvula. Even with incomplete extirpation of these structures, animals would become partially or totally resistant to motion sickness. In general, these operated animals exhibited normal responses to intravenously administered apomorphine or orally administered copper sulfate. These results indicate that motion stimulates the labyrinthine receptors, and the vestibular impulses traverse the nodulus and uvula of the cerebellum, and the chemoceptive emetic trigger zone, and finally reach the medullary vomiting center.