The interrelationships between gill chloride cell morphology and ionic uptake in four freshwater teleosts

• Published in: Canadian Journal of Zoology
• Main Authors: Perry, S. F., Goss, G. G., Laurent, P.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1992
• Subjects: Anguilla anguilla; European eel
• Online Access: http://dx.doi.org/10.1139/z92-245; http://www.nrcresearchpress.com/doi/pdf/10.1139/z92-245

We have investigated the role of the gill chloride cell in transbranchial Na + and Cl − uptake in four species of freshwater teleost maintained in water of identical ionic composition. The basic experimental protocol was to determine whether interspecific variability in the rates of whole body Na + or Cl − uptake could be accounted for by similar interspecific variability in the fractional area of branchial chloride cells exposed to the external environment. To investigate the underlying cause(s) of intraspecific variability, chronic (10 day) treatment with cortisol in each species was used as a tool to evoke variations in both the rates of ionic uptake and chloride cell morphology. Examination of transmission and scanning electron micrographs revealed distinctive chloride cell and pavement cell morphology in each species. The results of quantitative morphometry, based on analysis of scanning electron micrographs, demonstrated that European eel (Anguilla anguilla) possessed the lowest chloride cell fractional area on the filament epithelium (11 288 ± 2133 μm 2 /mm 2 ) followed, in increasing order, by brown bullhead catfish (Ictalurus nebulosus; 48 341 ± 7694 μm 2 /mm 2 ), tilapia (Oreochromis mossambicus; 85 194 ± 10 326 μm 2 /mm 2 ), and rainbow trout (Oncorhynchus mykiss; 146 333 ± 31 356 μm 2 /mm 2 ). With the exception of rainbow trout, chronic treatment with cortisol caused significant increases in the chloride cell fractional area of filament epithelium owing to enlargement of the surface area of individual chloride cells and (or) proliferation of chloride cells. Both the inter- and intra-specific differences in chloride cell fractional area were reflected by similar differences in whole body Cl − and Na + uptake. The results of correlation analysis revealed (with the exception of whole body Na + uptake in A. anguilla) significant correlations between chloride cell fractional area and the rates of ionic uptake within and among the four species that were examined. These data suggest that the chloride cell ...