Intrinsic mechanisms controlling the mammalian gastro-oesophageal sphincter deprived of extrinsic nerve supply

The oesophagus and gastro-oesophageal junction of 13 guinea-pigs and 14 3-week-old kittens were removed and placed in oxygenated Tyrode9s solution at 36 to 37° C. Sphincteric pressures were recorded before and after oesophageal distension. In these preparations changes in the tone of the gastro-oesophageal sphincter were observed in response to lower oesophageal distension. The sphincter of the guinea-pig responded by relaxation, whereas the sphincter of the kitten responded more often by contraction. The relaxation/contraction responses of the sphincter to oesophageal distension were independent of any extrinsic nerve supply and could be abolished by removal of a circular cuff of oesophageal muscle between the source of the stimulus and the gastro-oesophageal sphincter. The intramural mechanisms affecting gastro-oesophageal sphincteric tone probably are present in all mammals, including man.