Calcium permeation and blocking effect in human leukaemia cells
Joint Authors
Said M. V.
Faruq A. D.
Uwaydah, M. K.
Source
Sudan Medical Laboratory Journal
Issue
Vol. 1, Issue 1 (30 Jun. 2011)
Publisher
Omdurman Islamic University Faculty of Medical Laboratory
Publication Date
2011-06-30
Country of Publication
Sudan
Main Subjects
Topics
Abstract EN
Cell-attached and inside-out patch-clamp methods were employed to identify and characterize mechanosensitive (MS) ionic channels in the plasma membrane of human myeloid leukaemia K562 cells.
A reversible activation of gadolinium-blockable mechanogated currents in response to negative pressure application was found in 58 % of stable patches (n = 317).
I-V relationships measured with a sodium-containing pipette solution showed slight inward rectification.
Data analysis revealed the presence of two different populations of channels that were distinguishable by their conductance properties (17.
2 ± 0.
3 pS and 24.
5 ± 0.
5 pS), but were indistinguishable with regard to their selective and pharmacological properties.
Ion-substitution experiments indicated that MS channels in leukaemia cells were permeable to cations but not to anions and do not discriminate between Na+ and K +.
The channels were fully impermeable to large organic cations such as Tris+ and N-methyl-D-glucamine ions (NMDG +).
Ca2+ permeation and blockade of MS channels were examined using pipettes containing different concentrations of Ca2 +.
In the presence of 2 mM CaCl2, when other cations were impermeant, both outward and inward single-channel currents were observed ; the I-V relationship showed a unitary conductance of 7.
7 ± 1.
0 pS.
The relative permeability value, PCa / PK, was equal to 0.
75, as estimated at physiological Ca2+ concentrations.
Partial or full inhibition of inward Ca2 + currents through MS channels was observed at higher concentrations of external Ca2 + (10 or 20 mM).
No MS channels were activated when using a pipette containing 90 mM CaCl2.
Monovalent mechanogated currents Sud Med Lab J.
Vol (1) : 62-77 (2011) were not significantly affected by extracellular Ca2+ at concentrations within the physiological range (0-2 mM), and at some higher Ca2+ concentrations.
American Psychological Association (APA)
Said M. V.& Faruq A. D.& Uwaydah, M. K.. 2011. Calcium permeation and blocking effect in human leukaemia cells. Sudan Medical Laboratory Journal،Vol. 1, no. 1.
https://search.emarefa.net/detail/BIM-576098
Modern Language Association (MLA)
Said M. V.…[et al.]. Calcium permeation and blocking effect in human leukaemia cells. Sudan Medical Laboratory Journal Vol. 1, no. 1 (2011).
https://search.emarefa.net/detail/BIM-576098
American Medical Association (AMA)
Said M. V.& Faruq A. D.& Uwaydah, M. K.. Calcium permeation and blocking effect in human leukaemia cells. Sudan Medical Laboratory Journal. 2011. Vol. 1, no. 1.
https://search.emarefa.net/detail/BIM-576098
Data Type
Journal Articles
Language
English
Notes
Includes bibliographical references
Record ID
BIM-576098