Meyers J R, Copanas E H, Zottoli S J
Department of Biology, Williams College, Williamstown, Mass 01267, USA.
Brain Behav Evol. 1998;52(1):7-22. doi: 10.1159/000006548.
A comparative anatomical and behavioral approach was used to elucidate the role of medullary networks associated with Mauthner cells (M-cells) in determining the type of fast startle responses of elongate bony fish with an anguilliform type of locomotion. The M-cell initiates fast startle responses in goldfish and is thought to initiate such responses in other fish as well [Wilson, 1959; Eaton et al., 1977; Currie and Carlsen, 1987; Currie, 1991]. Goldfish M-cells have a specialized structure, termed an axon cap, that surrounds their axon hillock-initial segment region and is critical for the control of M-cell excitability. The M-cell axon cap is present in some elongate fish such as the African lungfish (Protopterus, Lepidosireniformes) and absent in others such as the American eel (Anguilla, Anguilliformes). The lungfish startle response is characterized by a rotation of the head and upper trunk, similar to the initial phase of the goldfish (Carassius, Cypriniformes) startle response. The American eel, on the other hand, displays a withdrawal-type startle response. We hypothesize that the withdrawal-type startle response of the American eel results from the absence of inhibitory networks associated with the M-cell axon cap. The correlation of the absence of an axon cap and a withdrawal-type startle response may be a general feature of all Anguilliformes and elongate ray-finned fish with an anguilliform type of locomotion.
采用比较解剖学和行为学方法，以阐明与莫特纳尔细胞（M细胞）相关的延髓网络在决定具有鳗形运动类型的细长硬骨鱼快速惊吓反应类型中的作用。M细胞引发金鱼的快速惊吓反应，并且被认为也能引发其他鱼类的此类反应[威尔逊，1959年；伊顿等人，1977年；柯里和卡尔森，1987年；柯里，1991年]。金鱼的M细胞具有一种特殊结构，称为轴突帽，它围绕着轴突丘 - 起始段区域，对控制M细胞的兴奋性至关重要。M细胞轴突帽存在于一些细长鱼类中，如非洲肺鱼（非洲肺鱼属，非洲肺鱼目），而在其他鱼类中不存在，如美洲鳗鲡（鳗鲡属，鳗鲡目）。肺鱼的惊吓反应特征是头部和上躯干的旋转，类似于金鱼（鲫属，鲤形目）惊吓反应的初始阶段。另一方面，美洲鳗鲡表现出退缩型惊吓反应。我们假设美洲鳗鲡的退缩型惊吓反应是由于缺乏与M细胞轴突帽相关的抑制性网络所致。轴突帽缺失与退缩型惊吓反应之间的相关性可能是所有鳗鲡目以及具有鳗形运动类型的细长辐鳍鱼的普遍特征。
