The Oral Absorption of Water

Abstract

A perfusion system was designed whereby the oral cavity of the rabbit under urethane anesthesia could be exposed to water in isolation from the remaining gastrointestinal system and the nasal cavity. Tritiated water was recovered from one external jugular vein within 40 s of the commencement of oral perfusion. The recovery rate increased linearly up to 200 s, arriving at a level of water averaging 1.7 × 10−3 ml/ml of venous blood. Rabbits dehydrated for 24 h were observed to have a relatively continuous water intake period ranging 85–200 s from the time of reexposure to water. It may be concluded that water can be absorbed from the mouth during the drinking period of a thirsty rabbit. Under normal circumstances the level of absorption can be assumed to be greater than the experimental because of the influences of muscular activity, blood flows, and increased areas of mucosal exposure. The data may be associated with the oropharyngeal metering of water intake.