Electromyographic Study of the Choledochoduodenal Junction and Duodenal Wall Muscle

Abstract

1. The action currents of a normal rabbit's choledochoduodenal junction and the duodenal wall at the same level both in their digestive process, were recorded by using two bipolar Ag-AgCl needle electrodes which were 0.3mm. in diameter and set with a interpolar distance of 1mm. 2. In the experiment, the action currents of the choledochoduodenal junction and the duodenal wall showed no marked difference in number and amplitude of grouped spikes, while there was an obvious difference observed in the intervals between spike groups. 3. According to the electromyographic variations caused by the administration of sympathomimetic and parasympathomimetic drugs, acetylcholine, pilocarpine and morphine hydrochloride were effective in bringing on acceleration of the action current of which acetylcholine the most powerful ; while amylnitrite and adrenaline worked for restraining the action current, and of the two, amylnitrite inhalation produced the more marked effect. Injection of atropine did not cause any noticeable change. In the experiment of infusing drugs into the duodenum, N/10 hydrochloric acid acted as an accelerator and 25% magnesium sulfate as a restraint; the same reactions were observed in the action current of the duodenum. Injection of morphine hydrochloride caused the choledochoduodenal junction and the duodenum to give forth two different spike patterns. 4. Altogether, the action current in the choledochoduodenal junction of a rabbit in its digestive process brings on a spike pattern different from that of the duodenum. This fact supplies us with an interesting suggestion relating to the bile flow mechanism.