Tokumasu M, Nakazono Y, Ide H, Akagawa K, Onimaru H
Faculty of Science and Engineering, Aoyama Gakuin University, Tokyo, 157-8572 Japan.
Jpn J Physiol. 2001 Oct;51(5):613-9. doi: 10.2170/jjphysiol.51.613.
We report on the optical imaging of spontaneous respiratory neuron bursts in the ventrolateral medulla (VLM) of medullary slices or brain stem-spinal cord preparations. A medullary slice with a thickness of 1.0-1.4 mm or brain stem-spinal cord from 0- to 4-d-old rats was stained with fluorescent voltage-sensitive dye, RH795. Optical signals were recorded as a fluorescence change by using an optical recording apparatus with a 128 x 128 photodiode array and a maximum time resolution of 0.6 ms. Motoneuronal activity was simultaneously recorded at the hypoglossal nerve roots or fourth cervical ventral roots. Fluorescence changes corresponding to the spontaneous inspiratory burst activity were detected in the hypoglossal nucleus and VLM in slice preparations, and in a limited area extending rostrocaudally in the VLM of the brain stem-spinal cord preparation. These measurements did not require signal averaging by multiple trials. Results suggest that inspiratory neurons are localized in more compact form at the level of the nucleus ambiguous than at the more rostral VLM, and that peak activity during the inspiratory phase propagates from the caudal to the rostral VLM. In 60% of brain stem-spinal cord preparations, weak and scattered fluorescence changes preceding the inspiratory burst activity were detected more predominantly in the rostral part of the VLM. The present findings show the feasibility of optical recordings for the in vitro analysis of spontaneous respiratory neuron activity in the medulla.
我们报告了延髓切片或脑干-脊髓标本腹外侧延髓（VLM）中自发性呼吸神经元爆发的光学成像。用荧光电压敏感染料RH795对厚度为1.0 - 1.4毫米的延髓切片或0至4日龄大鼠的脑干-脊髓进行染色。使用具有128×128光电二极管阵列且最大时间分辨率为0.6毫秒的光学记录设备，将光信号记录为荧光变化。同时在舌下神经根或第四颈腹根记录运动神经元活动。在切片标本的舌下神经核和VLM中，以及在脑干-脊髓标本VLM中沿前后方向延伸的有限区域内，检测到了与自发性吸气爆发活动相对应的荧光变化。这些测量不需要多次试验进行信号平均。结果表明，吸气神经元在疑核水平比在更靠前的VLM中以更紧凑的形式定位，并且吸气相期间的峰值活动从尾侧VLM向头侧VLM传播。在60%的脑干-脊髓标本中，在吸气爆发活动之前检测到的微弱且分散的荧光变化在VLM的头侧部分更为明显。本研究结果表明了光学记录用于体外分析延髓中自发性呼吸神经元活动的可行性。
