Electrophysiological properties of the Plasmodium Falciparum-induced cation conductance of human erythrocytes.

Abstract

Intraerythrocyte survival of the malaria pathogen Plasmodium Falciparum depends on the induction of the new-permeability-pathways (NPPs) in the host cell membrane. NPPs are characterized as anion- and organic osmolyte-permeable channels which also exhibit a low but significant permeability for inorganic cations. To disclose the electrophyiologial properties of this infection-induced cation permeability whole-cell currents were recorded in Plasmodium Falciparum-infected human erythrocytes (pRBC) using bath and pipette solutions with low Cl(-) concentrations. The data disclose a nonselective cation conductance (G(CAT)) which activated upon removal of extracellular Cl(-). Upon activation, G(CAT) was 0.3 +/- 0.05 nS (n=16) in control RBC and 2.0 +/- 0.3 nS (n = 32) in pRBC indicating an induction of G(CAT) during the infection. G(CAT) of pRBC exibited a relative permselectivity for monovalent cations of Cs(+)ñK(+)>Na(+)>Li(+) (P(Na)/P(K) ñ 0.5) with a significant permeability for Ca(2+). G(CAT) of pRBC was inhibited by NPPs blockers (furosemide and NPPB) and cation channel blockers (amiloride, EIPA, GdCl(3)) with the highest sensitivity to EIPA (IC(50)-0.5 microM). Most importantly, the blocker sensitivities differed between the infection-induced anion conductances and G(CAT) suggesting that G(CAT) and the anion conductances represent different channel proteins which in concert build up the NPPs.

• Authors: Christophe Duranton, Stephan Huber, Valérie Tanneur, Karl Lang, Verena Brand, Ciprian Sandu, Florian Lang
• Journal: Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology (Cell Physiol Biochem) Vol. 13 Issue 4 Pg. 189-98 ( 2003) ISSN: 1015-8987 [Print] Germany
• PMID: 12876376 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright 2003 S. Karger AG, Basel

Chemical References

• Calcium Channels
• Cations
• Amiloride
• ethylisopropylamiloride

Topics

• Amiloride (analogs & derivatives, pharmacology)
• Animals
• Calcium Channels (drug effects)
• Cations
• Erythrocytes (metabolism)
• Humans
• Ion Transport
• Patch-Clamp Techniques
• Plasmodium falciparum (physiology)