Influence of vestibular organ stimulation on stomach movement and respiration.

Some previous investigators have reported controversial results in the stomach movement in response to labyrinthine stimulation (1). The purpose of the present study was to investigate the influence of vestibular stimulation on the stomach movement and respiration in anesthetized cats, and to investigate the differences between increased and decreased responses of the stomach movement. This study used an electrophysiological technique: a bipolar stainless-steel stimulating electrode with a tip diameter of 20 microns introduced chronically into the anterior and/or lateral semicircular canal (2). The intragastric pressure was recorded by using a balloon-transducer system. Respiration was recorded by measurement of the thorax. When the peripheral labyrinth was stimulated, we found conflicting results in that the pressure in the stomach increased several times and sometimes decreased. Respiration usually became irregular or intensified. It seems that forced respiration may be involved in vestibular vomiting but we were unable to induce vomiting.