Bass A H
Brain Behav Evol. 1985;27(2-4):115-31. doi: 10.1159/000118725.
Among marine teleost fishes, one neuroeffector pathway for sonic communication consists of two components: a peripheral effector organ that consists of a swimbladder with associated 'drum' muscles, and a swimbladder or 'sonic' motor nucleus (SMN) located at the junction of the spinal cord and the medulla oblongata. Here, the organization of the SMN is compared in two unrelated groups of teleosts, the midshipmen, Porichthys notatus and P. myriaster, and the sea robin, Prionotus carolinus. Horseradish peroxidase (HRP), used as a retrograde tracer, revealed the position of the SMN in each species. While the SMN is a fused midline structure in midshipmen, it is bilateral in sea robins. The functional significance of these two contrasting patterns of organization remains to be explored. A third study group included mormyrid freshwater electric fish, which are also sonic. Mormyrids were included in part because an earlier study identified androgen-binding cells at a brain level comparable to that of the SMN of marine fishes. Using HRP methods, a swimbladder motor nucleus was identified at the caudal pole of the vagal motor column. However, the nucleus in mormyrids lies dorsal to the fourth ventricle and central canal, not ventral as it does in midshipmen and sea robins. Its position corresponds to the steroid-concentrating cells identified in a previous study.
在海洋硬骨鱼类中，声音交流的一条神经效应通路由两个部分组成：一个外周效应器官，它由一个带有相关“鼓”肌的鳔组成；以及一个位于脊髓和延髓交界处的鳔或“发声”运动核（SMN）。在此，对两种无关的硬骨鱼类——海鲈鱼（Porichthys notatus和P. myriaster）和海鲂（Prionotus carolinus）的SMN组织结构进行了比较。用作逆行示踪剂的辣根过氧化物酶（HRP）揭示了每个物种中SMN的位置。虽然SMN在海鲈鱼中是一个融合的中线结构，但在海鲂中是双侧的。这两种截然不同的组织结构模式的功能意义仍有待探索。第三个研究组包括也能发声的裸背电鳗科淡水鱼。将裸背电鳗科鱼类纳入研究部分是因为一项早期研究在与海洋鱼类SMN相当的脑水平上鉴定出了雄激素结合细胞。使用HRP方法，在迷走运动柱的尾极鉴定出了一个鳔运动核。然而，裸背电鳗科鱼类中的这个核位于第四脑室和中央管的背侧，而不像在海鲈鱼和海鲂中那样位于腹侧。它的位置与先前研究中鉴定出的类固醇浓缩细胞相对应。
