Please use this identifier to cite or link to this item: https://repositorio.inpa.gov.br/handle/1/16416
Title: Low pH and calcium effects on net Na+ and K+ fluxes in two catfish species from the Amazon River (Corydoras: Callichthyidae)
Authors: Matsuo, Aline Y.O.
Val, Adalberto Luis
Keywords: Calcium Ion
Potassium Ion
Sodium Ion
Animals Experiment
Catfish
Concentration (parameters)
Controlled Study
Exposure
Nonhuman
Ph
Potassium Transport
Regulatory Mechanism
River
Sodium Transport
Species Difference
Animalsia
Callichthyidae
Catfish
Corydoras
Corydoras Schwartzi
Issue Date: 2002
metadata.dc.publisher.journal: Brazilian Journal of Medical and Biological Research
metadata.dc.relation.ispartof: Volume 35, Número 3, Pags. 361-367
Abstract: The present study analyzes Na+ and K+ disturbances caused by low pH in two catfish species from the Amazon River. Corydoras adolfoi inhabits ion-poor, black-stained, low pH (3.5-4.0) waters, while C. schwartzi is native to ion-rich waters at circumneutral pH. Fish were exposed to pH 3.5 Ca2+-free, and Ca2+-enriched (∼500 μmol/l) water to determine the protective effects of calcium. Net Na+ and K+ fluxes were measured in the water collected from the fish experimental chambers. C. adolfoi was unable to control the Na+ efflux at low pH. exhibiting Na+ loss up to -594 ± 84 nmol g-1 h-1 during the first hour. After 3 and 6 h, net Na+ flux increased by 7- and 23-fold, respectively. In C. schwartzi, at pH 3.5, the initial high Na+ loss (-1,063 ± 73 nmol g-1 h-1) was gradually attenuated. A K+ loss occurred in both species, but remained relatively constant throughout exposure. High [Ca2+] affected ion losses in both species. C. adolfoi had 70% loss attenuation, indicating incapacity to control Na+ efflux. In C. schwartzi, elevated [Ca2+] completely prevented the Na+ losses caused by exposure to low pH. Rather different patterns were seen for K+ fluxes, with C. adolfoi showing no K+ disruption when exposed to low pH/high [Ca2+]. Thus, C. adolfoi loses Na+ during acid exposure, but has the ability to control K+ loss, while C. schwartzi controls diffusive Na+ loss but exhibits a slightly higher K+ loss. Ion balance was influenced by [Ca2+] at low pH in C. schwartzi but not in C. adolfoi.
metadata.dc.identifier.doi: 10.1590/S0100-879X2002000300012
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