ON THE SIGNIFICANCE OF NEURONAL GIANTISM IN GASTROPODS
ON THE SIGNIFICANCE OF NEURONAL GIANTISM IN GASTROPODS
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DOI：
10.2307/1542393
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发表时间：
1991-04-01
影响因子：
1.6
通讯作者：
GILLETTE, R
中科院分区：
文献类型：
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作者：
GILLETTE, R
腹足类和肺腹足类动物的中枢神经节神经元随着动物的成长而增大，有些甚至变成了名副其实的巨人。本文从比较的角度探讨神经元巨人症的起源和功能。对各种蛇支和肺门动物神经元特性的回顾表明，神经元的大小与突触后神经支配的程度直接相关。DNA内复制，导致部分或完全多倍体，支持巨大的软体动物神经元，因为它在真核细胞其他地方。显然，巨人症的功能意义在于增强物质的合成和运输，以扩大突触前功能。在较大的蜗牛中发现了巨大的神经元，它们支配着周围的大片区域；中间神经元和感觉神经元的放大程度较小，可能达到与外周效应器负载匹配的程度。神经元巨人症可能是行为简单、感觉不复杂的大型动物对外周神经支配的一种适应，这种适应使身体和中枢神经系统的生长不需要神经元数量的相应增加。在简单和复杂软体动物大脑的细胞特性的比较研究中，应该寻求对神经元巨人症的进化和适应意义的更全面的理解。
Neurons of the central ganglia of opisthobranch and pulmonate gastropods increase in size as the animals grow, some becoming veritable giants. The origins and functions of neuronal giantism are considered here from a comparative viewpoint. A review of the properties of identified neurons in a variety of opisthobranch and pulmonate species indicates that neuronal size is directly related to the extent of postsynaptic innervation. DNA endoreplication, resulting in partial or complete polyploidy, supports giantism in molluscan neurons as it does in eukaryotic cells elsewhere. Apparently, the functional significance of giantism is enhanced synthesis and transport of materials to serve an expanded presynaptic function.Giant neurons are found in larger snails where they innervate large areas of the periphery; interneurons and sensory neurons are enlarged to a lesser degree, probably to that which enables load-matching to the peripheral effectors. Neuronal giantism may be an adaptation for the innervation of the periphery in large animals with simple behaviors and uncomplex sensoria, this adaptation enabling growth of body and CNS without a proportionate increase in neuronal number. A more complete understanding of the evolutionary and adaptive significance of neuronal giantism should be sought in comparative studies of the cellular properties of simple and complex molluscan brains.