Eructation of gas through the gastroesophageal sphincter before and after truncal vagotomy in dogs.

The function of the gastroesophageal sphincter (GES) to eructate gas before and after vagotomy was investigated in conscious, fed dogs. Gastric and GES pressures were measured in 5 dogs, using a perfused 4-lumen catheter with a Dent sleeve. To induce eructation, nitrogen gas was insufflated (440 ml/min) into the stomach through 1 channel of the catheter. After base-line studies were completed on each dog, bilateral truncal vagotomy was performed 5 cm cranial to the diaphragm. Mean (+/- SE) GES pressure was 51.5 +/- 1 mm of Hg before vagotomy and 28 +/- 1.7 mm of Hg after vagotomy (P less than 0.001). Mean gastric contraction rates were the same, 4.91 +/- 0.11/min and 4.78 +/- 0.06/min in dogs before and after vagotomy, respectively. During insufflation, gastric pressures increased to 11.8 +/- 0.7 mm of Hg before eructation in dogs before vagotomy and to 18.4 +/- 0.8 mm of Hg in dogs after vagotomy (P less than 0.001). Eructation occurred at intervals of 1.79 +/- 0.09 minutes before vagotomy and 5.71 +/- 0.41 minutes after vagotomy (P less than 0.001). Atropine resulted in an interval of 1.98 +/- 0.18 minutes before vagotomy. Eructation was not seen in 2 dogs after vagotomy and was sometimes not seen in the 3 others. Gastroesophageal sphincter pressure in dogs before vagotomy began to decrease 4.5 +/- 0.2 s before the GES-pressure gradient disappeared, and GES pressure remained there for 5.3 +/- 0.3 s before the gradient began to return.(ABSTRACT TRUNCATED AT 250 WORDS)