Contractions of the caudal region of the oesophagus of the cat.

1. The motility of the most caudal part of the oesophagus has been investigated in cats which were decerebrated, had the whole of the central nervous system pithed or were anaesthetized with chloralose.2. Contractions of the most caudal region of the oesophagus were evoked by its stretch and the presence in it of HCl. These reactions were obtained in all types of preparations used.3. In decerebrate preparations oesophageal contractions occurred in response to the introduction of acid into the stomach. These were not obtained after the vagus nerves had been cut.4. Slight degrees of gastric distension stimulated oesophageal contractions, greater distension was inhibitory.5. Both reductions in oesophageal activity and contractions of the oesophagus were obtained with different parameters of stimulation of efferent vagal fibres.6. Excitatory and inhibitory effects on the oesophagus were obtained from stimulation of the central end of the vagus nerves cut in the abdomen or in the neck.7. In totally pithed preparations of cats stretch of one region of the oesophagus was found to modify the activity of a distant region of the oesophagus cranial or caudal to the site of distension.8. The reactions of the caudal oesophagus were abolished by atropine.9. The importance of vago-vagal reflexes in the modification of basically direct oesophageal responses has been discussed.