Kinetic studies of ion transport by fish gill epithelium.
Kinetic studies of ion transport by fish gill epithelium.
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鱼鳃上皮离子运输的动力学研究。
DOI：
10.1152/ajpregu.1980.238.3.r224
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发表时间：
1980
期刊：
影响因子：
--
通讯作者：
D. Evans
中科院分区：
文献类型：
--
作者：
D. Evans
大卫·埃文斯鱼鳃上皮细胞离子运输之动力学研究。Am. J. Physiol. 238（Regulatory Integrative Comp. Phvsiol. 7）：R224-R230，1980年。放射性同位素和电生理学技术使定量研究离子跨鱼上皮膜转运成为可能。目前的证据表明，淡水鱼从淡水中独立地提取Na'和Cl-，以分别交换血液中的NH'或H '和HCO或OH-。目前尚不清楚哪种替代离子交换系统在给定物种中起作用，并且提出可能存在替代交换系统以满足给定物种的特定代谢需求。它已被证明，这些交换系统的功能，酸碱调节，氮排泄，和CO？在淡水中，排泄以及离子调节是重要的，但似乎气体扩散和肾脏机制也可能起作用。因为排泄的需要高于一切，所以Na '/NH。T和可能的Na '/H'交换也发生在海鱼鳃上皮。然而，与口服相比，该系统呈现的Na+负荷似乎相对较小。c和可能的扩散Na'增益。海水鱼类中过量NaCl的挤出机制已经得到了很好的研究，但尚未确定。最近的动力学研究表明，Na'和Cl都被积极地挤出，分别交换海水K'和HCQ;然而，组织化学和放射自显影定位的建议运输酶Na'挤出（Na-K-ATP酶）表明，它是在错误的细胞位置，以促进这种直接交换系统。此外，分离的Cl--细胞上皮细胞向外运输Cl，但保持Na'处于被动平衡。尽管Na '-挤出机制的不确定性，哇巴因和硫氰酸盐的相互敏感性清楚地表明Na'和Cl-挤出是相关的。关于非硬骨鱼类物种的数据是不完整的。硬骨鱼;板鳃类;鳃上皮;鳃盖上皮; Na '; Cl-; H'; HCO，;酸碱调节; Na-K-ATP酶
EVANS, DAVID H. Kinetic studies of ion transport by fish gill epithelium. Am. J. Physiol. 238 (Regulatory Integrative Comp. Phvsiol. 7): R224-R230, 1980.-Radioisotopic and elec-c trophysiological techniques have enabled quantitative approaches to the study of ion transport across fish epithelial membranes. Present evidence indicates that freshwater fish extract Na’and Cl-, independently, from freshwater in exchange for blood NH,’or H’and HCO, or OH-, respectively. It is still unclear which of the alternative ion exchange systems function in a given species and it is proposed that alternative exchange systems may exist to meet specific metabolic needs of a given species. It has been shown that these exchange systems function in acid-base regulation, nitrogen excretion, and CO? excretion as well as ionic regulation in freshwater but it appears that gaseous diffusion and renal mechanisms may also play a role. Hecause of the overriding needs for excretion, Na’/NH. T and possibly Na’/H’ exchange also take place across the marine fish hranchial epithelium. However, the Na’load presented hv this svstem appears to be relatively small compared to oral.. c and possibly diffusional Na’gain. Mechanisms for the extrusion of excess NaCl in marine fish are well studied, but unsettled. Recent kinetic studies indicate that both Na’and Cl are actively extruded in exchange for seawater K’and HCQ;, respectively; however, histochemical and radioautographic localization of the proposed transport enzyme for Na’extrusion (Na-K-ATPase) indicate that it is in the wrong cellular position to promote such a direct exchange system. Further, isolated Cl--ceil epithelia transport Cl outward but maintain Na’in passive equilibrium. Despite the uncertainty about Na’-extrusion mechanisms, reciprocal ouabain and thiocyanate sensitivity indicate clearly that Na’and Cl-extrusion are linked. Data on nonteleostean species are fragmentary. teleost; elasmobranch; branchial epithelium; opercular epithelium; Na’; Cl-; H’; HCO,; acid-base regulation; Na-K-ATPase