Muscle function and structure of the esophagus of the baboon (Papio anubis).

A baboon (Papio anubis) was used as a model for the study of the physiology of the esophagus. This model closely resembles the human being phylogenetically and physiologically. Base-line lower esophageal sphincter pressure and peristaltic amplitude are similar to that of man. In addition, the anatomic transition from striated to smooth muscle is identical to that of the human esophagus. The sphincter-depressing effect of ketamine anesthesia was demonstrated.