Abstract:
Zebrafish (Danio rerio) have become an important model for integrative physiological research. Zebrafish inhabit a hypo-osmotic environment; to maintain ionic and acid-base homeostasis, they must actively take up ions and secrete acid to the water. The gills in the adult and the skin at larval stage are the primary sites of ionic regulation in zebrafish. The uptake of ions in zebrafish is mediated by specific ion transporting cells termed ionocytes. Similarly, in mammals, ion reabsorption and acid excretion occur in specific cell types in the terminal region of the renal tubules (distal convoluted tubule and collecting duct). Previous studies have suggested that functional regulation of several ion transporters/channels in the zebrafish ionocytes resembles that in the mammalian renal cells. Additionally, several mechanisms involved in regulating the epithelial ion transport during metabolic acidosis are found to be similar between zebrafish and mammals. In this article, we systemically review the similarities and differences in ionic regulation between zebrafish and mammals during metabolic acidosis. We summarize the available information on the regulation of epithelial ion transporters during acidosis, with a focus on epithelial Na⁺, Cl- and Ca2+ transporters in zebrafish ionocytes and mammalian renal cells. We also discuss the neuroendocrine responses to acid exposure, and their potential role in ionic compensation. Finally, we identify several knowledge gaps that would benefit from further study.
摘要:
斑马鱼(Daniorerio)已成为综合生理研究的重要模型。斑马鱼栖息在低渗透环境中;为了维持离子和酸碱稳态,它们必须积极吸收离子并向水中分泌酸。斑马鱼的成虫和幼体阶段的皮肤是离子调节的主要部位。斑马鱼中离子的摄取是由称为离子细胞的特定离子转运细胞介导的。同样,在哺乳动物中,离子重吸收和酸排泄发生在肾小管末端区域(远曲小管和集合管)的特定细胞类型中。先前的研究表明,斑马鱼离子细胞中几种离子转运蛋白/通道的功能调节类似于哺乳动物肾细胞中的功能调节。此外,发现在代谢性酸中毒过程中涉及调节上皮离子运输的几种机制在斑马鱼和哺乳动物之间是相似的。在这篇文章中,我们系统回顾了斑马鱼和哺乳动物在代谢性酸中毒时离子调节的异同。我们总结了关于酸中毒过程中上皮离子转运蛋白调节的现有信息,以上皮Na为重点,斑马鱼离子细胞和哺乳动物肾细胞中的Cl-和Ca2转运蛋白。我们还讨论了酸暴露的神经内分泌反应,以及它们在离子补偿中的潜在作用。最后,我们确定了几个知识差距,将受益于进一步的研究。