Spencer A N
J Neurobiol. 1979 Mar;10(2):95-117. doi: 10.1002/neu.480100202.
The gross and fine morphology of the major effector systems in the anthomedusan, Polyorchis penicillatus, is described and discussed in relation to the known physiological and behavioral properties of these systems. Swimming is controlled by an anastomosing network of giant neurons within the inner nerve ring and radial nerves. Although these neurons may be coupled by gap junctions it is likely that they form a syncytium. The photosensitivity of the "giants" is attributed to reflexive membranes within the cytoplasm. Giant neurons act as both the pre- and postsynaptic cell when forming synapses with other neurons of the inner nerve ring. Neuromuscular synapses between "giants" and the striated swimming muscle are found around the margin and along the radii. Swimming muscle cells are connected laterally by gap junctions and end-to-end by desmosomes which are sometimes elaborated with extra-thick filaments. Unstriated sphincter and radial muscles, the major muscles associated with crumpling, are both greatly folded over mesogloeal ridges and have processes that cross the mesogloea to contact the ring and radial canals, respectively. Synapses or other sites that might be responsible for exciting these muscles during crumpling have not been found. The ability of the endodermal lamella and canals to propagate action potentials can be accounted for by the numerous gap junctions that are seen in these tissues. The precise location where excitation is transferred to the nervous system to initiate crumpling is not known but epithelial bridges crossing the mesogloea are likely routes. Synapses between neurons originating in the outer nerve ring and tentacle longitudinal muscle can account for the control of tentacle length. Neurons of the outer nerve ring also synapse onto velar, radial fibers and the sphincter muscle. The inner and outer nerve rings have nervous connections. The organisation of the outer nerve ring and the arrangement of nerves within the endodermal plexus is described. A diagram showing the major connections and interactions of components of the effector systems is presented.
本文描述并讨论了花水母纲动物多枝多列仙水母主要效应系统的大体形态和精细形态，并将其与这些系统已知的生理和行为特性联系起来。游泳由内环神经和放射神经内的巨大神经元吻合网络控制。尽管这些神经元可能通过缝隙连接耦合，但它们很可能形成了一个合胞体。“巨型”神经元的光敏性归因于细胞质内的反射膜。巨型神经元在与内环神经的其他神经元形成突触时，既充当突触前细胞，也充当突触后细胞。“巨型”神经元与横纹肌游泳肌之间的神经肌肉突触位于边缘周围和沿半径方向。游泳肌细胞通过缝隙连接横向连接，通过桥粒端对端连接，桥粒有时会有额外的粗丝。无横纹的括约肌和放射肌是与褶皱相关的主要肌肉，它们都在中胶层嵴上大幅折叠，并有分别穿过中胶层与环管和放射管接触的突起。尚未发现可能在褶皱过程中刺激这些肌肉的突触或其他位点。内胚层薄片和管道传播动作电位的能力可以通过这些组织中大量的缝隙连接来解释。兴奋传递到神经系统以引发褶皱的确切位置尚不清楚，但穿过中胶层的上皮桥可能是途径。起源于外环神经和触手纵肌的神经元之间的突触可以解释触手长度的控制。外环神经的神经元也与缘膜、放射纤维和括约肌形成突触。内环神经和外环神经有神经连接。本文描述了外环神经的组织结构和内胚层神经丛内神经的排列。给出了一个显示效应系统各组成部分主要连接和相互作用的示意图。
