Study of Vestibulo-Autonomic Responses to Centrifugal Acceleration

本研究的目的是阐明前庭器官对心肺功能的影响。离心机产生较长时间(10min)的离心力，其水平臂长度为1.5m，计算机最大产量为15g。为了比较前庭的影响，将动物分为两组，一组为完整仓鼠(IH)，另一组为双侧迷路切除组(LTH)。分别从-X(从背部到腹部)、+Z(从头到尾)和-Z(从尾到头)三个方向对两只动物施加加速度。加载加速度的不同方向表现出不同的影响。+Z加速度(+Gz)对心功能的影响最大。+2Gz暴露仅引起心率和心输出量的轻微下降，但+4Gz暴露的动物有一半受到致命性损伤，心电图显示为房室传导阻滞。+Gz负荷下IH和LTH之间无明显差异。而-Z加速度(-Gz)在10g以下并不严重，但心率、心输出量和每分钟呼吸量均下降到加速的程度。LTH组的下降幅度大于IH组。这一事实表明，前庭器官可能通过自主神经系统向心肺器官发送一些防御性反射信号。

The aim of this study is to clarify how the vestibular apparatus does effect on the cardio-pulmonary functions. A relatively long period exposure (10 min) to centrifugal acceleration force were generated by a centrifuge, which has a horizontal arm length of 1.5 m, and produces up to 15 g by means of computer. In order to compare the vestibular influences, the animals used were divided into two groups, one with intact hamsters (IH), and the other with bilateral labyrinthectomized ones (LTH). Both animals were loaded by the acceleration from each one of 3 directions, -X (from back to abdomen), +Z (from head to tail) and -Z (from tail to head). Each direction of loading acceleration revealed different influences. The most effective change of cardiac function was caused by +Z acceleration (+Gz). Exposure of +2Gz caused only slight decrease of the heart rate and cardiac output, but a half of animals exposed +4Gz suffered a fatal damage, which was shown the atrio-venticular block by the ECG. No difference between IH and LTH was found by +Gz loading. While -Z acceleration (-Gz) were not serious up to 10 g, but the heart rate, the cardiac output, and minute volume of respiration were decreased in pallarel to the magnitude of acceleration. Those decreases were larger in LTH than in IH. This fact implies that the vestibular organ may send some defensive reflex signals to cardio-pulmonary organs through the autonomic nervous system.