Localized Pain Accompanying Faradic Excitation of the Stomach and Duodenum

Abstract

The following observations, hitherto unreported, were made during the course of experiments designed to test the reaction of the human gall bladder to faradic stimulation of the gastro-intestinal tract. 1

Eleven medical students cooperated in this undertaking, several of them submitting to repeated experimentation. The device selected for stimulating the gut tract was a standard Rehfuss tube enclosing a copper wire soldered to the metal olive at the end of the tube. The other electrode consisted of a moist pad fastened to the arm of the subject. Through this circuit was sent an induction current that was almost intolerable when tested by the lips, but which was not unbearable when applied to the gut, causing sensations varying from barely perceptible, gnawing sensations, to heartburn and sharp colicky pain. With the aid of fluoroscope and barium meal, it was ascertained that when the olive was pushed against the wall of the stomach the current caused ring contraction of the gut and then increased peristalsis distal to that point. In each case the duration of the current was 10 seconds.

Figure 1 (left) records observations made upon one student on 4 different days. The circles indicate varying positions of the electrode in the gut (as determined by X-rays); the dots the site of the pain area on the abdominal wall. With the subject prone, excitation of the mid-pyloric stomach was localized at the lower middle or left epigastric regions; of the pyloric antrum, at the lower middle or right epigastrium; of the pars superior (duod.) at the right umbilical or right supra-umbilical region; of the pars descendens at the right lower epigastric, the right umbilical, or the right scrotal region; of the pars inferior (duod.) at the mid-line just below the umbilicus.