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Age decline in the activity of the Ca2+-sensitive K+ channel of human red blood cells.
- Source :
-
The Journal of general physiology [J Gen Physiol] 2007 May; Vol. 129 (5), pp. 429-36. - Publication Year :
- 2007
-
Abstract
- The Ca(2+)-sensitive K(+) channel of human red blood cells (RBCs) (Gardos channel, hIK1, hSK4) was implicated in the progressive densification of RBCs during normal senescence and in the mechanism of sickle cell dehydration. Saturating RBC Ca(2+) loads were shown before to induce rapid and homogeneous dehydration, suggesting that Gardos channel capacity was uniform among the RBCs, regardless of age. Using glycated hemoglobin as a reliable RBC age marker, we investigated the age-activity relation of Gardos channels by measuring the mean age of RBC subpopulations exceeding a set high density boundary during dehydration. When K(+) permeabilization was induced with valinomycin, the oldest and densest cells, which started nearest to the set density boundary, crossed it first, reflecting conservation of the normal age-density distribution pattern during dehydration. However, when Ca(2+) loads were used to induce maximal K(+) fluxes via Gardos channels in all RBCs (F(max)), the youngest RBCs passed the boundary first, ahead of the older RBCs, indicating that Gardos channel F(max) was highest in those young RBCs, and that the previously observed appearance of uniform dehydration concealed a substantial degree of age scrambling during the dehydration process. Further analysis of the Gardos channel age-activity relation revealed a monotonic decline in F(max) with cell age, with a broad quasi-Gaussian F(max) distribution among the RBCs.
- Subjects :
- Anemia, Sickle Cell blood
Anemia, Sickle Cell metabolism
Cell Movement
Erythrocytes drug effects
Glycated Hemoglobin
Hemoglobins metabolism
Humans
In Vitro Techniques
Ionophores pharmacology
Normal Distribution
Reference Values
Valinomycin pharmacology
Aging
Calcium metabolism
Dehydration metabolism
Erythrocytes metabolism
Intermediate-Conductance Calcium-Activated Potassium Channels metabolism
Potassium metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0022-1295
- Volume :
- 129
- Issue :
- 5
- Database :
- MEDLINE
- Journal :
- The Journal of general physiology
- Publication Type :
- Academic Journal
- Accession number :
- 17470662
- Full Text :
- https://doi.org/10.1085/jgp.200709766