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PubMed · 8392039

pCMPS-induced changes in lens membrane permeability and transparency.

J Sanderson·G Duncan
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Abstract

PURPOSE: To investigate the role of externally facing membrane protein sulfhydryl groups in controlling lens permeability and transparency using the impermeant sulfhydryl complexing agent p-chloromercuriphenyl sulfonate (pCMPS). METHODS: Membrane permeability changes were studied by measuring lens voltage and resistance. Ion movements were monitored by measuring 22Na+ and 45Ca2+ fluxes, and internal free calcium was monitored by ion-selective microelectrodes. Opacification was quantified by photographing and analyzing back-scattered light. RESULTS: pCMPS, at concentrations above 1 microM, produced a depolarization of membrane potential and decrease in membrane resistance. These changes were accompanied by a marked stimulation in 22Na+ and 45Ca2+ influxes into the lens. There was a concomitant loss of lens transparency, mainly in the bow region. The pCMPS-induced electrical changes could be prevented by substituting N-methyl-D-glucamine for Na+ in the external medium. Na(+)-free solution alone increased 45Ca2+ influx, and the addition of pCMPS further stimulated the influx. Quinine (300 microM) was found to reduce the pCMPS-induced stimulation of 22Na+ and 45Ca2+ influxes and also to reduce opacification. CONCLUSIONS: pCMPS at low concentrations induces many of the cation permeability changes previously found to occur with age and cataract in the lens. The fact that quinine can ameliorate pCMPS-induced changes in ion movements and opacification suggests a novel approach for membrane-based anticataract strategies.

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4-ChloromercuribenzenesulfonateAnimalsCalciumCataractCell Membrane PermeabilityElectrophysiologyExtracellular SpaceLens, CrystallineMeglumineMembrane PotentialsMicroelectrodesOrgan Culture TechniquesQuinineRatsSodiumJournal ArticleResearch Support, Non-U.S. Gov't

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J Sanderson, G Duncan. 1993. pCMPS-induced changes in lens membrane permeability and transparency.. https://pubmed.ncbi.nlm.nih.gov/8392039/

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