Mechanoreceptors and Minimal Reflex Activity Determining Claw Laterality In Developing Lobsters
Mechanoreceptors and Minimal Reflex Activity Determining Claw Laterality In Developing Lobsters
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机械感受器和最小反射活动决定龙虾发育中的爪侧向性
DOI：
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发表时间：
1992
期刊：
影响因子：
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通讯作者：
J. Pearce
中科院分区：
文献类型：
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作者：
C. Govind;J. Pearce
双侧不对称的龙虾Homarus americanus的成对的爪子是确定在第四和第五少年阶段的差异反射活动;具有更大的活动的一方成为破碎机，而对侧成为刀具。幼年龙虾饲养在这一关键时期的底层，不能把握或减少输入主要是内部mechanoreceptors（本体感受器）（通过切割的趾和chordotonal器官或tenotomizing爪张开器或关闭肌肉）未能开发破碎机爪，因此保持双侧对称：他们开发成对的刀具爪。因此，反射活动的本体感受成分涉及将爪神经节的初始偏侧化到破碎机和切割器侧。此外，龙虾与一个单一的爪子饲养没有一个底层开发了一个破碎机的完整的一面，只有当完整的爪子行使。在未行使的条件下，反射活动之间的差异与一只爪子和一侧没有一个不足以发展的破碎机爪的完整的一面。一个最小量的反射活动是必要的发展破碎机。在两只爪子都有这种最小活动量的情况下饲养的龙虾会发展出不对称的爪子，而不是成对的破碎爪。这意味着，爪神经节最初随机地一侧化为压碎侧，抑制了对侧也成为压碎侧。这就可以解释为什么我们没有培育出有成对破碎爪的龙虾，为什么它们很少在野外被发现。
Bilateral asymmetry of the paired claws of the lobster Homarus americanus is determined during the fourth and fifth juvenile stages by differential reflex activity; the side with the greater activity becomes the crusher while the contralateral side becomes the cutter. Juvenile lobsters reared during this critical period with a substratum that could not be grasped or with reduced input from predominantly internal mechanoreceptors (proprioceptors) (achieved by cutting the dactyl and its chordotonal organ or by tenotomizing the claw opener or closer muscles) failed to develop a crusher claw and hence remained bilaterally symmetrical: they developed paired cutter claws. Therefore, the proprioceptive component of the reflex activity is implicated in bringing about the initial lateralization of the claw ganglion into a crusher and a cutter side. Moreover, lobsters with a single claw reared without a substratum developed a crusher on the intact side only if the intact claw was exercised. In the unexercised condition, differences in reflex activity between the side with a claw and the side without one were insufficient for the development of a crusher claw on the intact side. A minimal amount of reflex activity is necessary for the development of a crusher. Lobsters reared with this minimal amount of activity in both claws developed asymmetrical claws rather than paired crusher claws. This means that initial lateralization of the claw ganglion into a crusher side, on a random basis, inhibited the opposite side from also becoming a crusher. This would explain why we failed to produce lobsters with paired crusher claws and why they were seldom found in the wild.