228 



Scientific Proceedings (121). 



99 (1846) 



Preliminary report on the effects of vagus stimulation on the dog's 

 stomach and the influence of asphyxia on these effects. 



By Z. BERCOVITZ. 



[From the Hull Physiological Laboratory of the University of Chicago 

 and Physiological Laboratory of Baylor Medical College, 

 Dallas, Texas.] 



In a previous report 1 attention was called to the fact that in 

 the turtle repeated vagus stimulation was followed by a progres- 

 sive decrease in the gastric response to each stimulation. It was 

 further pointed out in another report 2 that the stomach could 

 not be tetanized by prolonged vagus stimulation, also that reduc- 

 tion in the temperature of the turtle was followed by a decreased 

 gastric response to vagus stimulation. These facts seemed to 

 indicate that in the turtle a complex neuro-muscular mechanism 

 controlled the response of the stomach to vagus stimulation. 



The object of this study therefore was to determine if the dog's 

 stomach would respond to vagus stimulation in the same manner 

 as the turtle's stomach. 



Methods. 



The dogs used in this study were decerebrated in order to avoid 

 the depressing influence of an anesthetic. 



The balloon method was used for recording gastric contractions. 

 The balloon was introduced into the stomach through (a) healed 

 gastric fistula; (b) through slit in the anterior wall of the stomach 

 near the pylorus; (c) through the mouth and esophagus; id) 

 through the duodenum. The results were the same in all cases. 



In most cases a simultaneous blood pressure tracing was made 

 from the carotid artery and in others the chest was opened, 

 artificial respiration given and the heart observed directly. 



To produce asphyxia of the stomach a lifting ligature was 

 placed under the thoracic aorta. 



The animals were cooled by packing them in cracked ice until 

 the rectal temperature dropped to the desired point. As a rule 

 i\ to 2\ hours were required to cool the decerebrated dog to 23 0 C. 



1 Bercovitz and Rogers, Amer. Journ. Physiol., 1921, lv, 323. 

 7 Rogers and Bercovitz, Amer. Journ. Physiol., 1921, lvi, 257. 



