Rhythmic motor activity in thin transverse slice preparations of the fetal rat spinal cord.
Rhythmic motor activity in thin transverse slice preparations of the fetal rat spinal cord.
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DOI：
10.1152/jn.01029.2003
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发表时间：
2004-07
影响因子：
2.5
通讯作者：
K. Nakayama;H. Nishimaru;N. Kudo
中科院分区：
文献类型：
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作者：
K. Nakayama;H. Nishimaru;N. Kudo
在胎儿期的最后一周，大鼠脊髓中形成了产生类似运动的节律性运动活动的网络。我们研究了早在胚胎日 (E) 16.5 时取自胎鼠的腰脊髓横切切片中诱导的协调节律性运动活动。在薄至 100 微米的切片中，5-羟色胺 (5-HT) 的浴应用诱导用 Calcium Green-1 葡聚糖标记的运动神经元节律性 [Ca(2+)](i) 升高。尽管 100 微米切片左侧和右侧的活动之间没有时间相关性，但节律性 [Ca(2+)](i) 升高的频率与完整腰脊髓中的频率相似。在所有腰椎切片中观察到这种有节奏的 [Ca(2+)](i) 升高。此外，同时阻断谷氨酸、甘氨酸和 GABA(A) 受体可以消除节律活性，这表明这些受体介导的突触传递对于这些切片中节律的产生非常重要。在从腰脊髓任何节段水平获取的厚度超过 200 微米的切片中发现左右两侧之间的同步节律活动。在这些制剂中，连合神经元与同侧运动神经元同步激活。这些结果表明，足以产生协调节律活动的神经元网络包含在 E16.5 处单个腰椎节段的一半中。这种脊髓切片是研究脊髓中神经元机制和节律产生发展的有前途的实验模型。
Networks generating locomotor-like rhythmic motor activity are formed during the last week of the fetal period in the rat spinal cord. We investigated the coordinated rhythmic motor activity induced in transverse slice preparations of the lumbar spinal cord taken from fetal rats as early as embryonic day (E) 16.5. In slices as thin as 100 microm, bath-application of 5-hydroxytryptamine (5-HT) induced rhythmic [Ca(2+)](i) elevations in motoneurons labeled with Calcium Green-1 dextran. The rhythmic [Ca(2+)](i) elevations were similar in frequency to that in the intact lumbar spinal cord, although there was no temporal correlation between the activity in the left and right sides of 100-microm slices. Such rhythmic [Ca(2+)](i) elevations were observed in the slices taken from all lumbar segments. Moreover, the rhythmic activity was abolished by simultaneous blockade of glutamate, glycine, and GABA(A) receptors, indicating that synaptic transmission mediated by these receptors is important for the generation of the rhythm in these slices. Synchronous rhythmic activity between the left-right sides was found in slices thicker than 200 microm taken from any segmental level of the lumbar spinal cord. In these preparations, commissural neurons were activated synchronously with ipsilateral motoneurons. These results indicate that the neuronal networks sufficient to generate coordinated rhythmic activity are contained in one-half of a single lumbar segment at E16.5. Such spinal cord slices are a promising experimental model to investigate the neuronal mechanisms and the development of rhythm generation in the spinal cord.