Use este identificador para citar ou linkar para este item: http://repositorio.inpa.gov.br/handle/123/855
Título: Low pH and calcium effects on net Na+ and K+ fluxes in two catfishes species from the Amazon River (Corydoras: Callichthyidae)
Autor(es): Aline Yuri Otsuki Matsuo
Adalberto Luis Val
Assunto: Amazônia
Peixes
Adaptação ao Ambiente
ISSN: 0100-879X
Revista: Brazilian Journal of Medical and Biological Research
Volume: 35
Resumo: 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.
URI: http://repositorio.inpa.gov.br/handle/123/855
ISSN: 0100-879X
DOI: https://dx.doi.org/10.1590/S0100-879X2002000300012
Aparece nas coleções:Coordenação de Biodiversidade (CBIO)

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