Department of Pathology, Immunology and Laboratory Medicine, University of Florida, College of Medicine, P.O. Box 100275, Gainesville, FL 32610, USA.
J Comp Physiol B. 2012 Jan;182(1):1-39. doi: 10.1007/s00360-011-0601-3. Epub 2011 Jul 7.
For teleost fish living in seawater, drinking the surrounding medium is necessary to avoid dehydration. This is a key component of their osmoregulatory strategy presenting the challenge of excreting excess salts while achieving a net retention of water. The intestine has an established role in osmoregulation, and its ability to effectively absorb fluid is crucial to compensating for water losses to the hyperosmotic environment. Despite this, the potential for the teleost intestine to serve as a comparative model for detailed, integrative experimental studies on epithelial water transport has so far gone largely untapped. The following review aims to present an assessment of the teleost intestine as a fluid-transporting epithelium. Beginning with a brief overview of marine teleost osmoregulation, emphasis shifts to the processing of ingested seawater by the gastrointestinal tract and the characteristics of intestinal ion and fluid transport. Particular attention is given to acid-base transfers by the intestine, specifically bicarbonate secretion, which creates the distinctly alkaline gut fluids responsible for the formation of solid calcium carbonate precipitates. The respective contributions of these unique features to intestinal fluid absorption, alongside other recognised ion transport processes, are then subsequently considered within the wider context of the classic physiological problem of epithelial water transport.
对于生活在海水中的硬骨鱼类来说，饮用周围的介质是避免脱水所必需的。这是它们渗透调节策略的一个关键组成部分，因为它们需要排泄多余的盐分，同时保持水分的净保留。肠道在渗透调节中起着重要的作用，其有效吸收液体的能力对于补偿高渗环境中的水分损失至关重要。尽管如此，硬骨鱼肠道作为上皮细胞水分运输的详细综合实验研究的比较模型的潜力，迄今尚未得到充分利用。以下综述旨在评估硬骨鱼肠道作为一种液体转运上皮。首先简要概述海洋硬骨鱼的渗透调节，然后将重点转移到胃肠道对摄入海水的处理以及肠道离子和液体转运的特征上。特别关注肠道的酸碱传递，特别是碳酸氢盐的分泌，这产生了明显碱性的肠道液体，负责形成固体碳酸钙沉淀。然后，在经典的上皮细胞水分运输生理问题的更广泛背景下，考虑这些独特特征以及其他公认的离子转运过程对肠道液体吸收的各自贡献。
