Human platelet calcium mobilisation in response to beta-amyloid (25-35): buffer dependency and unchanged response in Alzheimer's disease

In the present study, the effects of beta -amyloid (25-35) (A beta (25-35)) upon calcium signalling by the human platelet has been investigated. When assays were conducted using HEPES buffers, A beta (25-35), but not the inac tive peptide A beta (35-25), produced a robust increase in intracellular ca lcium that remained after removal of extracellular calcium but was abolishe d by the phospholipase C inhibitor U-73122. There was no significant differ ence bt tween the calcium response to A beta (25-35) in platelets from pati ents with Alzheimer's disease and from age-matched controls. In contrast to the robust effects on calcium mobilisation in HEPES buffers, very little c alcium response to A beta (25-35) was seen when Krebs (pH 7.8) buffer was u sed. (C) 2001 Elsevier Science Ltd. All rights reserved.