Abstract
Electrical activity of the esophageal muscle in dog was studied with a view in elucidating the nature of nervous innervation.
In resting phase esophageal muscle was kept quiescent and no muscle activity could be recorded. To obtain action potential by direct stimulation more intensive stimulus was required than the other skeretal muscles in the neck. The muscle responses induced by stimulation of the recurrent laryngeal nerve had variable time delay ranged from 2 to 10 msec. These results might be the consequence of either variable fiber size contained in the efferent nerve or mode of distribution of the endplate in the muscles.
A reflex response in the esophageal muscle was evoked by stimulation of the internal superior laryngeal nerve. A response was a asynchronous type with a latency of about 20 msec.
A relatively long latency and the repetitive nature of the discharge indicated that a response should be a polysynaptic reflex.
Sometimes stimulation of the recurrent laryngeal nerve evoked, besides a direct response from the muscle, a secondary response of considerably lower amplitude after an interval of about 20 msec.
The origin and nature of a secondary response were discussed.
