Swimming rhythm generation in the caudal hindbrain of the lamprey
Swimming rhythm generation in the caudal hindbrain of the lamprey
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DOI：
10.1152/jn.00851.2017
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发表时间：
2018-05-01
影响因子：
2.5
通讯作者：
Buchanan, James T.
中科院分区：
文献类型：
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作者：
Buchanan, James T.
脊髓已被确定为脊椎动物运动节律的产生部位，但研究表明幼鱼和两栖动物的尾后脑也可以产生运动节律。在这里，我们研究了成年七鳃鳗（Petromyzon marinus 和 Ichthyomyzon unicuspis）的尾部后脑是否具有产生游泳节奏的能力。七鳃鳗的后脑-脊髓过渡区包含双侧体细胞运动神经元柱，通过脊髓枕（S-O）神经投射到头部的几块肌肉。在脑干-脊髓-肌肉准备中，当对脊髓进行短暂的电刺激引起游泳活动时，这些肌肉被发现有节奏地左右交替地爆发和收缩。在没有肌肉的情况下，分离的脑干-脊髓制剂也会在 S-O 神经中产生交替的左右爆发（即虚构的游泳）。 S-O 神经爆发先于同侧第一脊髓腹根发生的爆发。使用神经系统横向切口对 S-O 区域进行物理隔离后，当向沐浴溶液中添加谷氨酸时，S-O 神经仍然表现出左右交替的节律性爆发。我们得出的结论是，七鳃鳗的 S-O 区域包含一个游泳节律发生器，它产生每个游泳周期的主导运动神经爆发，然后沿着脊髓传播以产生向前游泳。后脑-脊髓过渡区的 S-O 区可能在调节速度方面发挥作用。七鳃鳗游泳时的转向和头部方向。新的和值得注意的尽管已经明确运动节律的产生发生在脊椎动物的脊髓中。目前尚不清楚成年脊椎动物神经系统的后脑是否也能产生运动节律。在这里，我们证明成年七鳃鳗孤立的后脑-脊髓过渡区可以产生游泳节奏。此外，后脑的游泳爆发导致脊髓第一段发生爆发。
The spinal cord has been well established as the site of generation of the locomotor rhythm in vertebrates, but studies have suggested that the caudal hindbrain in larval fish and amphibians can also generate locomotor rhythms. Here, we investigated whether the caudal hindbrain of the adult lamprey (Petromyzon marinus and Ichthyomyzon unicuspis) has the ability to generate the swimming rhythm. The hindbrain-spinal cord transition zone of the lamprey contains a bilateral column of somatic motoneurons that project via the spinooccipital (S-O) nerves to several muscles of the head. In the brainstem-spinal cord-muscle preparation, these muscles were found to burst and contract rhythmically with a left-right alternation when swimming activity was evoked with a brief electrical stimulation of the spinal cord. In the absence of muscles, the isolated brainstem-spinal cord preparation also produced alternating left-right bursts in S-O nerves (i.e., fictive swimming). and the S-O nerve bursts preceded the bursts occurring in the first ipsilateral spinal ventral root. After physical isolation of the S-O region using transverse cuts of the nervous system, the S-O nerves still exhibited rhythmic bursting with left-right alternation when glutamate was added to the bathing solution. We conclude that the S-O region of the lamprey contains a swimming rhythm generator that produces the leading motor nerve bursts of each swimming cycle, which then propagate down the spinal cord to produce forward swimming. The S-O region of the hindbrain-spinal cord transition zone may play a role in regulating speed. turning, and head orientation during swimming in lamprey.NEW & NOTEWORTHY Although it has been well established that locomotor rhythm generation occurs in the spinal cord of vertebrates. it was unknown whether the hindbrain of the adult vertebrate nervous system can also generate the locomotor rhythm. Here, we show that the isolated hindbrain-spinal cord transition zone of adult lamprey can generate the swimming rhythm. In addition, the swimming bursts of the hindbrain lead the bursts occurring in the first segment of the spinal cord.