Site of emetic action of oral copper sulfate in dogs. (I) Thresholds of various portions of gastrointestinal tract to locally applied copper sulfate.

Emetic thresholds to copper sulfate administered into the Pavlov pouch, Forrest pouch, Thiry fistulas of the jejunum and ileum, and duodenal, jejunal and ileal catheters were measured in dogs to conjecture the site of emetic action of copper sulfate. The oral emetic threshold had been measured preoperatively. In the stomach, the pyloric antrum had a high sensitivity, while the corpus had a low sensitivity to the topically applied copper sulfate. In the intestine, the sensitivity was high in the duodenum, whereas a low sensitivity was noted in the jejunum. Almost no sensitivity was observed in the ileum. Thus it would appear that the site of the emetic action of copper sulfate was the pyloric antrum and/or duodenum.