ELECTROMYOGRAPHIC STUDIES OF THE DUODENUM AND THE CHOLEDOCHO-DUODENAL JUNCTION

Abstract

Rabitts were used in these experiments. The spike potentials of the duodenum and choledocho-duodenal junction, the pressure in the common bile duct and the discharge of bile into the duodenum were recorded simultaneously in vivo.In the duodenum and the choledocho-duodenal junction, the rate of the rhythmic burst of spike potentials was 12-16 cycles/min.Similar results were obtained in both regions by the administrations of acetylcholine, prostigmine, bethanechol chloride, pilocarpine, atropine, adrenaline, morphine, cholecystokinin, secretin and amyl-nitrite. Thus, the action of the choledocho-duodenal junction is not independent of that of the duodenum.The pressure in the common bile duct rises simultaneously with the appearance of the spike potentials of the choledocho-duodenal junction.The discharge of bile into the duodenum was prevented by the muscle contraction of the choledocho-duodenal junction, when the bursts of spike potentials appeared. Bile was discharged into the duodenum by relaxation of the choledochoduodenal junction. When the pressure in the common bile duct was kept constant at about 80mm H2O, the discharge of bile into the duodenum was increased by the administration of C. C. K. during the resting intervals of the remarkable bursts of spike potentials.