The vestibulo-autonomic function viewed from cardiac responses in centrifuged monkeys.
Vestibulo-autonomic function was examined as the change of cardiac parameters (HR and SV) to +Gz and -Gx accelerations for 1,000 s in intact and bilaterally labyrinthectomized monkeys. Under anesthetized conditions, HR and SV slightly changed to +2Gz acceleration in both monkeys. In +3Gz acceleration, changes were remarkable and significant. HR increased in intact monkeys by as much as 30% while it decreased in labyrinthectomized monkeys, although a moderate initial increase was observed. SV decreased in intact as well as labyrinthectomized monkeys, but the reduction was significant and larger for the latter. This implies that vestibular input could modulate autonomic function. For larger +Gz, both intact and labyrinthectomized monkeys could tolerate no more due to severe cardiac dysfunction (rapid HR and SV decrease) which appeared soon after +4Gz application. In case of -Gx application, HR increased, although slightly, in proportion to the amplitude of applied -Gx in both monkeys, with less changes in labyrinthectomized ones. SV hardly changed in smaller -Gx, while it increased in larger -Gx. Difference between intact and labyrinthectomized monkeys was observed in -6Gx and -8Gx conditions.
Department of Neurophysiology, Gifu University, School of Medicine, Japan.
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Miyata
D000054:Acceleration; D000818:Animals; D001341:Autonomic Nervous System / Q000502:physiology*; D007758:Ear, Inner / Q000502:physiology; D006112:Gravitation; D006321:Heart / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology; D008251:Macaca; D012399:Rotation; D013318:Stroke Volume / Q000502:physiology; D014724:Vestibular Function Tests