3 Ion Transport and Gill Atpases
1984; Academic Press; Linguagem: Inglês
10.1016/s1546-5098(08)60182-x
ISSN1557-8011
Autores Tópico(s)Reproductive biology and impacts on aquatic species
ResumoThis chapter describes the ion transport and gill ATPases in the fish gills. The gill epithelium is located between two liquid compartments of very different ionic composition. The gills are not only the site of entry for selected ions essential to life but also for the extrusion of other ions, such as HCO3-, NH3+ , and H+, which are the ionic forms of metabolic by-products. The magnitude of unidirectional fluxes, as well as the degree and direction of net fluxes, is dependent on the equilibrium established between the fish and its environment. Membranes are gently treated with ionic detergents, such as deoxycholate, dodecyl sulfate, or chaotropic agents, to release proteic constituents that are less strongly associated with phospholipids, (Na+, K+)-ATPase remaining in situ. Euryhaline species are an attractive model to compare branchial physiology from the adaptation medium and to relate physiological and biochemical aspects of ionic transport. The Ca2+-ATPase is also a membrane ATPase whose role in the cell is essential and evident, but it could also play a role in transepithelial transport and be implicated in the regulation of plasma Ca2+ concentration.
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