Morphological and functional characterization of a novel Na+/K+-ATPase-immunoreactive, follicle-like structure on the gill septum of Japanese banded houndshark, Triakis scyllium
Morphological and functional characterization of a novel Na+/K+-ATPase-immunoreactive, follicle-like structure on the gill septum of Japanese banded houndshark, Triakis scyllium
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日本带状猎犬 Triakis scyllium 鳃隔膜上新型 Na /K -ATP 酶免疫反应性滤泡样结构的形态和功能特征
DOI：
10.1007/s00441-012-1344-5
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发表时间：
2012
影响因子：
3.6
通讯作者：
Susumu Hyodo
中科院分区：
文献类型：
--
作者：
Souichirou Takabe;Keitaro Teranishi;Shin Takaki;Makoto Kusakabe;Shigehisa Hirose;Toyoji Kaneko;Susumu Hyodo
在硬骨鱼中，鳃除了具有呼吸气体交换的主要功能之外，还充当重要的离子调节器官，这一点已得到证实。然而，对于软骨鱼类，鳃的离子调节功能仍然知之甚少。尽管在软骨鱼类中也发现了富含线粒体（MR）的细胞，但这些细胞被认为主要在酸碱调节中发挥作用。在这项研究中，除了已经在鳃丝和鳃片中描述过的NKA免疫反应性MR细胞之外，我们还发现了一种由具有基底外侧表达的Na+/K+-ATP酶（NKA）的细胞组成的新型聚集结构。这些细胞聚集体被称为滤泡排列的富含 NKA 的细胞（滤泡 NRC），仅在丝状海绵体区域和鳃隔膜的丝状间隙的静脉网的上皮衬里中发现。滤泡NRC形成单层滤泡结构，具有通向外部环境的大管腔。滤泡NRC的特征在于：（i）顶膜上发育良好的微绒毛，（ii）基底外侧膜不太明显的折叠，以及（iii）典型的连接结构，包括细胞之间的深层紧密连接。此外，细胞质中还观察到大量囊泡，其中一些囊泡与侧膜融合。滤泡NRC表达Na+/H+交换器3和Ca2+转运蛋白1。因此，滤泡NRC具有吸收性离子调节细胞的特征，这表明软骨鱼鳃对体液稳态的贡献可能比之前认为的更重要。
In teleost fishes, it is well-established that the gill serves as an important ionoregulatory organ in addition to its primary function of respiratory gas exchange. In elasmobranch fish, however, the ionoregulatory function of the gills is still poorly understood. Although mitochondria-rich (MR) cells have also been found in elasmobranch fish, these cells are considered to function primarily in acid-base regulation. In this study, we found a novel aggregate structure made up of cells with basolaterally-expressed Na+/K+-ATPase (NKA), in addition to NKA-immunoreactive MR cells that have already been described in the gill filament and lamella. The cell aggregates, named follicularly-arranged NKA-rich cells (follicular NRCs), were found exclusively in the epithelial lining of the venous web in the cavernous region of the filament and the inter-filamental space of the gill septum. The follicular NRCs form a single-layered follicular structure with a large lumen leading to the external environment. The follicular NRCs were characterized by: (i) well-developed microvilli on the apical membrane, (ii) less prominent infoldings of the basolateral membrane and (iii) typical junction structures including deep tight junction between cells. In addition, large numbers of vesicles were observed in the cytoplasm and some of them were fused to the lateral membrane. The follicular NRCs expressed Na+/H+exchanger 3 and Ca2+transporter 1. The follicular NRCs thus have the characteristics of absorptive ionoregulatory cells and this suggests that the elasmobranch gill probably contributes more importantly to body fluid homeostasis than previously thought.