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Effects of Amphotericin B on Gill Water Permeability
Author(s) -
Tomicek Nanette J.,
Robertson John C.
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.a824-b
Subject(s) - gill , barrier function , mucus , paracellular transport , membrane , biophysics , secretion , chemistry , osmotic shock , microbiology and biotechnology , tight junction , amphotericin b , biology , permeability (electromagnetism) , biochemistry , fish <actinopterygii> , ecology , fishery , antifungal , gene
Fish gills are an intriguing system in which to examine barrier epithelial function and physiological exchange; regulation of the movement of water, ions, and other substances are primary gill functions. Freshwater fish inhabit significantly hypoosmotic environments, and the greatly expanded and attenuated exchange surfaces of the gill exacerbate the homeostatic challenges of an inwardly‐directed osmotic gradient. Freshwater fish have high gill plasma membrane cholesterol content, suggesting barrier membrane composition may act in restricting gill water permeation. Amphotericin B is a polyene macrolide antibiotic that acts clinically by binding to fungal membrane sterols, forming pore complexes which compromise membrane barrier integrity. We hypothesized that amphotericin B would readily form pore complexes with cholesterol in gill barrier membranes, leading to disrupted membrane function marked by water influx. Excised gill arches were incubated in either control hypoosmotic solutions or amphotericin B‐containing solutions – incubation media also contained calcium, which restricts paracellular water movement. Water influx was quantified as gill arch weight gain over time. Using this assay system, the concentration‐dependent effects of amphotericin B on osmotic water uptake were of particular interest. The impact of amphotericin B exposure on gill epithelial cell structure and mucus secretion were also assessed by microscopy.