AJP - Regulatory, Integrative and Comparative Physiology, Vol 255, Issue 3 464-R469, Copyright © 1988 by American Physiological Society
Oscillating heat flow from rabbit's pinna
F. S. Mohler and J. E. Heath
Department of Physiology and Biophysics, University of Illinois, Urbana 61801.
Thermal characteristics of the pinnae of the ears of New Zealand White
rabbits (Oryctolagus cuniculus) were measured with an infrared imaging
system, and vasomotor oscillations were observed to occur spontaneously in
the pinnae of all rabbits at an ambient temperature of 20 degrees C.
Measured fluctuations in surface temperature were used to characterize the
observed vasomotor oscillations, whereas heat loss from the pinnae was
calculated using the mean pinna temperatures. The pulsing related to
thermoregulation had a mean frequency of approximately 0.025 Hz with a mean
amplitude of approximately 0.35 degrees C. When surface temperature was
measured simultaneously from both pinnae of individual rabbits, the thermal
pulsing was synchronous in the two pinnae. Many of the characteristics of
the vasomotor rhythm measured in the pinnae of rabbits were consistent with
an active and controlled oscillation, and a possible thermoregulatory role
for a controlled vasomotor oscillation is discussed.
