Local cooling prolongs oesophageal transit in humans

The influence of local cooling on oesophageal transit was studied in eight healthy volunteers by oesophageal radionuclide transit. Compared with lukewarm (18 degrees C) water a significantly prolonged mean transit time (MTT) was found after ingestion of cold liquid (4 degrees C) and a slightly shorter MTT with 50 degrees C. The effect was of short duration lasting less than 2 min. The effect of atropine, morphine and naloxone, on the influence of local cooling was evaluated. Morphine (7 x 5 mg i.v.) abolished the effect of cooling on MTT. Naloxone (1 x 6 mg i.v.) reduced the effect of cooling, but the difference between 4 degrees C and 19 degrees C was significant still. Atropine (1 mg i.v.) had no effect on the increase in MTT at 4 degrees C. It is concluded that in humans local cooling increases oesophageal MTT. Local warming shortened MTT slightly. The abolishment of the influence of cooling by morphine suggests that opioids may be involved.