Calcium Entry Blockers in Cardiovascular and Cerebral Dysfunctions [electronic resource] /
2 The free internal Ca+ concentration in human red cells is set according to the leak 2 and-pump principle: There is a finite passive Ca+ influx at the physiological 2 2 Ca+ -gradient across the membrane which is compensated by Ca+ pumping in the outward direction with a rate given by the degree of saturation of the A TP-fuelled Ca 2 pump at the steady-state internal Ca+ concentration. Simons (1982) recently devised a method allowing the measurement of the steady 2 2 state internal Ca+ concentration. Cells are suspended in media of different Ca+ con 2 2 tent whose Ca+ concentration is monitored by a Ca+ -selective electrode. When the cells are lysed (by digitonin) there is an upward or downward deflection of the elec 2 trode signal. At the point of zero deflection, the cellular Ca+ concentration equals that 2 of the medium. The result is, that in fresh human red blood cells the Ca+ concentra tion is ;;;; O.4,uM (this is an upper estimate; the true value may be considerably lower).
Main Authors: | , , , |
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Format: | Texto biblioteca |
Language: | eng |
Published: |
Dordrecht : Springer Netherlands,
1984
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Subjects: | Medicine., Cardiology., Medicine & Public Health., |
Online Access: | http://dx.doi.org/10.1007/978-94-009-6033-6 |
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Summary: | 2 The free internal Ca+ concentration in human red cells is set according to the leak 2 and-pump principle: There is a finite passive Ca+ influx at the physiological 2 2 Ca+ -gradient across the membrane which is compensated by Ca+ pumping in the outward direction with a rate given by the degree of saturation of the A TP-fuelled Ca 2 pump at the steady-state internal Ca+ concentration. Simons (1982) recently devised a method allowing the measurement of the steady 2 2 state internal Ca+ concentration. Cells are suspended in media of different Ca+ con 2 2 tent whose Ca+ concentration is monitored by a Ca+ -selective electrode. When the cells are lysed (by digitonin) there is an upward or downward deflection of the elec 2 trode signal. At the point of zero deflection, the cellular Ca+ concentration equals that 2 of the medium. The result is, that in fresh human red blood cells the Ca+ concentra tion is ;;;; O.4,uM (this is an upper estimate; the true value may be considerably lower). |
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