Relationship of Ear Vein Pressure and Carotid Blood Flow To Body Temperature in the Rabbit

Abstract

Small vein pressure has been measured in the ear of the anesthetized rabbit at different body temperatures. It is high (20 to 35 cm HOO) when the animal is hot and low (8 to 19 cm H2O) when the animal is cold. There is a reactive state at intermediate core temperature in which venous pressure shows abrupt changes and periods of fluctuation. Changes in ear skin temperature and ipsilateral carotid blood flow accompany and parallel the changes in ear small vein pressure. It is postulated that the changes in small vein pressure result from nervously induced changes in caliber of arterial vessels in the ear, probably thermoregulatory in nature.