Active NaCl absorption across posterior gills of hyperosmoregulating Chasmagnathus granulatus
| Autor: | Onken, H., Tresguerres, M., Luquet, C.M. |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2003 |
| Předmět: |
Gills
Inhibitor Ion substitution Brachyura Biological Transport Active Sodium Chloride Strophanthus gratus electrolyte balance Absorption ion transport Osmoregulation Crustacea Flux measurement active transport Animals Animalia animal Anthranilic Acids Ouabain comparative study Ussing chamber Crab gill article Chasmagnathus granulata gill Water-Electrolyte Balance electrophysiology Short-circuit current Chasmagnathus granulatus anthranilic acid derivative Acetazolamide fenamic acid Transepithelial conductance Decapoda (Crustacea) physiology metabolism |
| Zdroj: | J. Exp. Biol. 2003;206(6):1017-1023 Biblioteca Digital (UBA-FCEN) Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales instacron:UBA-FCEN |
| Popis: | Split lamellae of posterior gills of Chasmagnathus granulatus adapted to 2.5‰ salinity were mounted in a modified Ussing chamber. With NaCl-saline on both sides of the preparation a transepithelial voltage (Vte) of 4.1±0.5 mV (outside positive) was measured. After voltage-clamping, the negative short-circuit current (Isc) amounted to -142±21 μA cm-2 at a conductance (Gte) of 44±5 mS cm-2. Substitution of either chloride (by nitrate) or sodium (by choline) on both sides of split gill lamellae significantly reduced Isc (by 70-80%) and Gte (by 30-50%). External CsCl (but not BaCl2 or furosemide) inhibited the negative Isc without affecting Gte. Addition of ouabain, BaCl2 or diphenylamine-2-carboxylate to the internal bath inhibited Isc at unchanged Gte. Internal acetazolamide did not affect Isc or Gte across split gill lamellae. Unidirectional Na+ influx across isolated and perfused posterior gills, however, was reduced by internal acetazolamide by approximately 20% at constant Vte. The results suggest that posterior gills of hyperosmoregulating C. granulatus display a high conductance epithelium that actively absorbs NaCl in a coupled way by an electrogenic mechanism similar to that seen in the thick ascending limb of Henle's loop and, to a minor degree, by an electroneutral mechanism, presumably via apical Na+/H+and Cl-/HCO3--antiports. Fil:Tresguerres, M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Luquet, C.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. |
| Databáze: | OpenAIRE |
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