[Cold and warm thermoregulation by oropharynx area and esophagus]

After being ingested, food and liquids suffer a thermal regulation process, which adapts them immediately to the body temperature by means of the mucosa diffusion. We have not found bibliographical information about this matter yet.

1) To describe the reaction of the oropharynx area and the esophagus by heat and coldness. 2) To compare both areas reaction.

Six patients (three men, three women, Age: mean 42 years old, SD 11.8), healthy individuals without both gastrointestinal and systemic disease that could after microcirculation.

Temperature measurement of liquid at mouth entrance and at 24 cm and 38 cm from dentary superior arcade using two thermocouples. Deglution of 40 ml of hot water (X 60 degrees C at entrance) or cold water (X 4 degrees C) in two draughts. Temperature measurement at both thermocouples at the end of deglution (time = 0 (zero)) and every 10 seconds. Random sequences every 30 minutes.

Using water at 60 degrees C, the temperature descended to 42 degrees C in the distal end. The oropharynx region dissipated 45% of the initial temperature while the esophagus completed the other 55%. The esophagus itself dissipated 65.6% of the 12.2 degrees C in time = 0 (zero). After 40 seconds the temperature reached the normal body temperature. In the case of the iced water (4 degrees C), the total work consisted on increasing temperature 33.6 degrees C to the normal corporal temperature. The 68.45% of the difference between the initial and the final temperature was obtained by the oropharynx region and the rest by the esophagus. In time = 0 (zero) the temperature increased up to 30 degrees C and the esophagus only contributed with 28.3% of the total work. The normal corporal temperature was reached after 40 seconds. It was observed a significant difference in the heating capacity between the oropharynx region and esophagus (p > 0.001). There was also a significant difference in the oesophagus itself between heat and coldness in time = 0 (zero) ¿65.6% (heat) Vs. 28.3% (coldness), 0.02 > p > 0.01¿ and values between time = 0 (zero) and 10-40 seconds (p > 0.001).

1) The ability of cooling was similar in both regions. 2) In the oropharynx region the capacity of heating was higher (voluntary time of deglution) than in the esophagus region. 3) The esophagus initial response before coldness was slower than oropharynx region's one. The buccal retention was greater. 4) Before both stimulus, normal corporal temperature was reached after 40 seconds.

The isothermation of coldness and heat would work through the same mechanism: the mucosa vasodilatation and the increase of blood flow. This hypothesis would be valid for all the mucosa of the digestive tract. This mechanism could be altered in inflammatory diseases. Iced water washings on bleeding wounds be counter-productive. The persistence of extreme temperatures in the environment modifies the structure of the esophagus mienteric plexus (Auerbach's plexus). Frequent ingestion of fluids above 60 degrees C would be a predisponent factor for esophagus cancer.