Coordination and modulation of locomotion pattern generators in Drosophila larvae:: Effects of altered biogenic amine levels by the tyramine β hydroxlyase mutation
Coordination and modulation of locomotion pattern generators in Drosophila larvae:: Effects of altered biogenic amine levels by the tyramine β hydroxlyase mutation
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DOI：
10.1523/jneurosci.4749-05.2006
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发表时间：
2006-02-01
影响因子：
5.3
通讯作者：
Wu, CF
中科院分区：
文献类型：
--
作者：
Fox, LE;Soll, DR;Wu, CF
果蝇幼虫的向前运动是由节律性的收缩波组成的，这些收缩被认为是由分段组织的中央图案生成器产生的。我们系统地描述了半完整的野生型和突变型幼虫在运动收缩波期间的尖峰活动模式。我们以前已经证明，Tβh(NM18)突变体，改变了章鱼胺和酪胺的水平，有运动缺陷。通过记录节段性神经传入，研究了驱动腹壁肌肉收缩波的神经元活动的协调性。与运动波同时发生的节律性爆发活动在野生型幼虫中经常观察到，但在Tβh(Nm18)突变体中很少看到。在切断节段神经与CNS后，野生型和Tβh(NM18)幼虫的远端残端都消除了这些中心产生的模式活动。有模式的活动持续存在于近端残肢，剥夺了来自外围的感觉反馈。同时的记录显示，不同数据段之间的爆发活动存在延迟，距离较远的数据段延迟更大。相反，在单个节段内的双边记录显示，在野生型和Tβh(NM18)幼虫中，支配每个半节段的神经具有良好的同步活动模式。值得注意的是，尽管Tβh(NM18)突变体的自发活动高度不规则，但通过头部或尾部刺激可以诱发出有节律的爆发和波动模式。这些观察表明，生物胺在运动模式产生的启动和调节中发挥了作用。这里提出的技术可以很容易地扩展到检查其他突变体的运动运动程序。
Forward locomotion of Drosophila melanogaster larvae is composed of rhythmic waves of contractions that are thought to be produced by segmentally organized central pattern generators. We present a systematic description of spike activity patterns during locomotive contraction waves in semi-intact wild-type and mutant larval preparations. We have shown previously that T beta h(nM18) mutants, with altered levels of octopamine and tyramine, have a locomotion deficit. By recording en passant from the segmental nerves, we investigated the coordination of the neuronal activity driving contraction waves of the abdominal body-wall muscles. Rhythmic bursts of activity that occurred concurrently with locomotive waves were frequently observed in wild-type larvae but were rarely seen in T beta h(nM18) mutants. These centrally generated patterned activities were eliminated in the distal stumps of both wild-type and T beta h(nM18) larvae after severing the segmental nerve from the CNS. Patterned activities persisted in the proximal stumps deprived of sensory feedback from the periphery. Simultaneous recordings demonstrated a delay in the bursting activity between different segments, with greater delay for segments that were farther apart. In contrast, bilateral recordings within a single segment revealed a well synchronized activity pattern in nerves innervating each hemisegment in both wild-type and T beta h(nM18) larvae. Significantly, rhythmic patterns of bursts and waves could be evoked in T beta h(nM18) mutants by head or tail stimulation despite their highly irregular spontaneous activities. These observations suggest a role of the biogenic amines in the initiation and modulation of motor pattern generation. The technique presented here can be readily extended to examine the locomotion motor program of other mutants.