Inductograph method for recording muscle activity, especially pyloric sphincter physiology

¹ Division of Physiology, University of Tennessee Medical Units, Memphis, Tennessee

The inductograph method for registering in vivo muscle activity under physiological conditions is described. The method is applied to a study of the physiology of the pyloric sphincter region of well-trained, unanesthetized dogs, but is readily applicable for similar studies of the heart, uterus, skeletal muscle, etc. The motor activity of the pyloric sphincter and the pyloric antrum during fasting, feeding and gastric evacuation; the response of these regions to parasympatheticomimetic and sympatheticomimetic stimulation; and the role of the sphincter in gastric evacuation is presented. These studies show that the pyloric sphincter and the pyloric antrum are either quiescent and relaxed or the pyloric sphincter contracts momentarily in a rhythmic manner four to six times a minute in response to each propagated antral peristaltic wave. The inherent rhythm of the pyloric sphincter region is almost impossible to alter, but one or more contraction cycles may be inhibited by excitement, epinephrine, atropine, etc. or the inherent rhythm in a quiescent sphincter may be made manifest by feeding, pilocarpine, etc.