Evidence for a random entry of Ca2+ into human red cells

Under the influence of a Gardos channel activator, N5309, acting through an increase of the channels Ca2+ sensitivity, it is found that the single population behavior of a suspension of human red cells, showing normal distributed osmotic resistance and density, after addition of NS309 in a time dependent manner changes to a two population distribution, with an increasing fraction of cells having high osmotic :resistance or high density. The increase with time of the high resistance fraction can be fitted to an exponential, with a time constant corresponding to about 50 min. Since the 'remaining' cell fraction is practically unchanged, this points to a sudden random activation of the individual cells. caused by Ca2+ entry through a channel like pathway. (c) 2008 Elsevier B.V. All rights reserved.