The membrane of erythrocytes infected with malaria parasites is highly permeable to a large variety of solutes, including anions, carbohydrates, amino acids, nucleosides, organic and inorganic cations and small peptides. The altered permeability is presumed to be due to the activation of endogenous dormant channels, the new permeability pathways. The latter have been studied by different techniques—isosmotic lysis and tracer fluxes—and recently by patch-clamping. Here we analyze all available published data and we show that there is generally a good agreement between the two first methods. From the fluxes we calculate the number of channels per cell using reasonable assumptions as to the radius of the channel, and assuming that penetration through the channel is by diffusion through a water-filled space. The number of channels so calculated is <10 for most solutes, but ~400 for anions and the nucleosides thymidine and adenosine. This latter number is not far from that calculated from patch-clamp experiments. However, the anion flux measured directly by tracer is an order of magnitude larger than expected from conductance measurements. We conclude that the new permeability pathways consist of two types of channels; one is present in small number, and is charge- and size-selective. The other type is about 100-fold more abundant and is anion-selective, but does not admit non-electrolytes other than perhaps nucleosides.
The Journal of Membrane Biology – Springer Journals
Published: Jan 1, 2003
It’s your single place to instantly
discover and read the research
that matters to you.
Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.
All for just $49/month
Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly
Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.
All the latest content is available, no embargo periods.
“Whoa! It’s like Spotify but for academic articles.”@Phil_Robichaud