损毁或阻滞面神经核腹内侧区对呼吸节律的影响

实验用兔,在乌拉坦静脉麻醉,自然呼吸或三碘季铵酚麻痹,人工通气条件下进行。观察了损毁或阻滞面神经核腹内侧区(VMNF)对呼吸节律的影响。结果如下:1.单侧损毁或利多卡因局部阻滞 VMNF 区可引起双侧膈神经放电时间延长,此效应在切断双侧颈迷走神经后尤为明显;2.膈神经吸气性放电的递增速度无明显改变。上述结果提示:VMNF 区在中枢呼吸节律调制中具有重要作用,可能是吸气切断机制负反馈神经元回路中的一个重要结构。

EFFECTS ON RESPIRATORY RHYTHMICITY BY LESION OR FOCAL BLOCK IN VENTROMEDIAL REGION OF NUCLEUS FACIALIS

Experiments were performed on 42 urethane-anesthetized rabbits of both sexes. The rabbits were either spontaneously breathing or gallamine paralyzed and artificially ventilated. Efferent phrenic nerve activity was recorded with bipolar silver electrodes. The experiment results were as follows: Unilateral mechanical lesion of focal block by microinjection of lidocaine (2%, 1 microliter) in the ventromedial region of nucleus facialis (VMNF) consistently caused apneustic-type breathing associated with no significant changes in the rate of rise of inspiratory activity. The expiratory time (Te) was only slightly affected or not changed at all. Some increase in Te was present only when a very strong apneustic effect was evoked. Respiratory effects of focal block by lidocaine in the region of VMNF were not accompanied by changes in blood pressure. No significant changes in respiratory rhythm were observed when lidocaine is microinjected in the nearby regions of VMNF. The results suggest that VMNF appears to be involved in an inspiratory off-switch mechanism.