Studies on the transit of the content in the chicken gastro-intestine. II. Relationship between movements of gizzard and duodenum and the transit of contents in the small intestine

In their previous report, the authors suggested that some part of the contents of the duodenum and ileum might be transferred conversely into the gizzard in chickens. It has been presumed that the antiperistalsis of the duodenum may probably be one of the factors of this phenomenon. Therefore, the present experiments were carried out to observe the relationship between the movements of the gizzard and duodenum and the transit of the contents of the duodenum. 1. By the abdominal-window method, it was witnessed that the movement of the gizzard was a strong and globular contractile one, that the peristalsis of the duodenum was an induced movement, and that immediately after the end of peristalsis occurred the antiperistalsis once or three times. 2. Relationship of the difference in the time of starting between the movement of the gizzard and that of the duodenum was observed simultaneously by the electromyographic, mechanographic, and abdominal-window methods. It was clear that the peristalsis of the duodenum occurred in the contractile period of the gizzard and that the antiperistalsis of the duodenum appeared in the relaxing period of the gizzard. The contractile pressure of the movement of the gizzard was 150-170 mm Hg. 3. Approximately 100 mg of bilirubin was measured in the gizzard. A volume of 0.2 ml of the marker (Na2&lt15&gtCrO4) warmed at 38°C was injected selectively into the duodenum through a cannula which had been inserted chronically into the hepatic bile duct. In 1 hour, 18.9% of the dosed radioactivity was distributed in the gizzard. 4. In an in vivo experiment, atropine (0.2 mg/kg intramuscularly) suppressed markedly the contractile force and frequency of the movement of the gizzard and of the peristalsis of the duodenum. On the other hand, the contractile force of the antiperistalsis of the duodenum decreased slightly, but its frequency increased markedly. In these conditions, the same volume of the marker was injected into the duodenum, but no dosed radioactivity was distributed in the gizzard in 1 hour. The quantity of the marker distributed in the upper segment of the duodenum was larger in an atropinized chicken than in an intact chicken. It was approximately equal to that distributed in the gizzard in the intact chicken. There was no difference in the quantity of the marker in the lower segment of the duodenum or in the small intestine between the atropinized and the intact chickens. 5. From these experimental results, it was made clear