NaCl absorption across split gill lamellae of hyperregulating crabs: Transport mechanisms and their regulation

Pharmacological characterisation of apical Na+ and Cl– transport mechanisms of the anal papillae in the larval mosquitoAedes aegypti

“…In frog skin, the gradient drives Na + across the apical membrane through epithelial Na + channels (Ehrenfeld and Klein, 1997). A similar mechanism has been shown in crustacean gill (Onken and Riestenpatt, 1998) and in fish gill (Reid et al, 2003). Another proposed mechanism for Na + uptake involves the Na + /H + exchangers; however, it has been suggested that this mechanism would only be feasible under brackish or saline water conditions as the low Na + concentration in freshwater would not be sufficient for Na + /H + exchange (see Parks et al, 2008).…”

“…On the basal side of the epithelium, Cl -exits the cytosol through Cl -channels, and this movement is supported by the combined actions of apical V-type H + -ATPase and basal Na + /K + -ATPase generating a cytosol negative gradient (see Onken and Riestenpatt, 1998). For freshwater fish gills, pharmacological and molecular evidence for the involvement of Cl -/HCO 3 -exchange in Cl -uptake has recently been provided Bayaa et al, 2009).…”

The effects of hypoxia on active ionic transport processes in the gill epithelium of hyperregulating crab, Carcinus maneas

“…We suggest that this trade-off between an increase of oxygen availability by alteration of mitochondria morphology and reduction of costs for active ion transport under hypoxia in crab posterior gills, represents an osmorespiratoy compromise enabling the animal to maintain hyperosmotic conditions at least under short-term hypoxic conditions. Similarly to the Carcinus posterior gill (Onken and Riestenpatt, 1998) the thick ascending limb of vertebrate kidneys is also an ion absorptive epithelium. Both epithelia are equipped with an apical Na + / K + /2 Cl − cotransporter, and K + channels at both sides of the epithelia and a basolaterally located Na + ,K + -ATPase (Greger, 1985;Gamba and Friedman, 2009).…”

“…Reversible block of Isc in the present study suggests a modification in which energy consuming processes are down regulated during hypoxia (Boutilier, 2001). Since the crustacean gill has been characterized as a leaky epithelium (Onken and Riestenpatt, 1998)), with a relatively high ionic permeability, we also studied the effect of hypoxia on electrical conductance, across the epithelium. Oxygen limitation is generally considered an impairment of mitochondrial respiration and thus ATP synthesis.…”

Transporte de cálcio em células isoladas de hepatopâncreas do caranguejo dulcícola Dilocarcinus pagei: efeito do ATP e Ca2+

“…Mecanismos evolutivos responsáveis pelo aumento da independência dos organismos em relação às flutuações das concentrações osmóticas do ambiente incluem a diminuição da permeabilidade das superfícies corporais a água e íons (SHAW, 1959;HARRIS, 1975;GREENAWAY, 1981) Um modelo proposto atualmente para a tomada de NaCl em crustáceos (para revisões veja PÉQUEX et al;PÉQUEUX, 1995;ONKEN & RIESTENPATT, 1998) sugere que a tomada de Na + é independente de Cl -e ocorre por canais apicais para (TSE et al, 1994;MONTERO et al, 1995;KENDALL et al, 1996;BYGRAVE & BENEDETTI, 1996). Algumas proteínas como calsequestrina (MACLENNAN & WONG, 1971;BEARD et al, 2004) e calreticulina (FLIEGEL et al, 1989;GELEBART et al, 2005) (BEZPROZVANNY et al, 1991).…”