Effects of intracellular calcium on lens membrane permeability.
Curr Eye Res
; 4(6): 693-701, 1985 Jun.
Article
em En
| MEDLINE
| ID: mdl-2411472
ABSTRACT
The present investigation was designed to assess whether lens membrane permeability is affected by changes in levels of intracellular calcium. Lanthanum, an inhibitor of Ca-ATPase, affected an increase in the concentration of intracellular calcium (Cai) measured in cortical fiber cells. Preculture of lenses in lanthanum (1.0mM) caused an accumulation of 36Cl during subsequent culture at a rate three-fold higher than control lenses. Changes in calcium levels, however, were not responsible for the observed flux changes because a 40mV depolarization was observed to occur prior to a significant increase in calcium levels. The non-specific effects of lanthanum and other potential inhibitors of calcium transport were avoided by preculturing lenses in an ion-HEPES medium containing 20mM calcium chloride. In lenses with a six-fold increase in calcium levels there resulted only a 10% increase in 36Cl uptake over a 3 hr period. 86Rb efflux was also measured and the rate constant was unchanged compared to control lenses. Calcium accumulation did lead to a small (8mV) depolarization which may account for the small increase in chloride accumulation. By light microscopy, morphology of cortical lens fibers and the epithelium appeared unchanged in the calcium-loaded lens. The results provide little evidence that an increase in Cai leads to acute changes in lens membrane permeability.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Líquidos Corporais
/
Permeabilidade da Membrana Celular
/
Cálcio
/
Líquido Intracelular
/
Cristalino
Limite:
Humans
Idioma:
En
Revista:
Curr Eye Res
Ano de publicação:
1985
Tipo de documento:
Article