In pursuance of an investigation of oesophageal physiopathology, a study has been made of the problem of the functional regulation of the inferior oesophageal sphincter in the light of new findings. Experiments carried out on six dogs made it possible to study functional modifications of the oesophagus after vagotomy, completing the technique by administering pentagastrin for the first time in vivo. Radiological and mano metric controls showed in the post-operative period a dilated oesophagus with a fall, in the lower third, of normal pressure values that did not undergo change, unlike what happened in the non-denervated oesophagus after administration of pentagastrin. The results obtained show that the integrity of the nervous structures is not only necessary for the perfect coordination of oesophageal peristalsis, but vital for normal functional response of the inferior oesophageal sphincter, since gastrin action is always mediated by release of acetylcholine by the post-gangliar vagal nerve endings.