Meeting Abstract

P3.147  Monday, Jan. 6 15:30  Variable Sensitivity of Lab Mice to Fluctuating Acceleration SWIDERSKI, D.L.*; KAPPY, M.; RAPHAEL, Y.; Univ. of Michigan, Ann Arbor dlswider@umich.edu

The vestibular organs of the inner ear play a critical role in maintaining balance and orientation. The dimensions of these organs can differ greatly between species that differ in locomotor ability or inhabit environments differing in spatial complexity. Tests of locomotor performance are commonly used to infer differences in vestibular function; however, locomotor performance can be influenced by many other factors. Thus, we are investigating the utility of involuntary physiological response to vestibular stimulation. Following studies on motion-sickness in humans, we tested for temporary shifts of body temperature of mice exposed to fluctuating high G acceleration. Mice were positioned on a rotating arm with the anteroposterior axis perpendicular to the plane of rotation. An automated controller generating alternating centripetal accelerations of 2G and 6G, for 10 second intervals, over a span of 2 minutes. Core body temperature was measured before acceleration, immediately after, and at regular subsequent intervals. We tested wildtype and affected mice from C57BL/6 (B6) colonies maintained for studies of vestibular mutations, wild-types lesioned bilaterally with streptomycin, and wildtype CD-1 mice. Wildtype female B6s typically exhibited a temporary 2-3° C drop but affected females did not. Also, mice that did have a temperature shift lost that response after streptomycin treatment. In contrast, wildtype male B6 mice from the same colony, generally had a smaller drop of <1.5°, and male CD1 mice showed no drop or an increase of up to 1.5°. Thus, brief exposure to controlled fluctuation of hyper-G acceleration can be used to test for loss of peripheral vestibular function under some conditions but differences between sexes and strains may reflect variations in how stress modulates physiology.