Gastro-Conray does not alter resting lower oesophageal sphincter pressure in normal human subjects

The effect of ingestion of 60 ml sodium iothalamate (Gastro-Conray; Maybaker)--a radiographic contrast medium--on resting lower oesophageal sphincter (LOS) pressure was studied in 10 normal human volunteers. Compared with a barium meal, which does cause a fall in LOS pressure, Gastro-Conray did not affect the sphincter tone. The importance of this is discussed.