Human platelet calcium mobilisation in response to β-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 inactive peptide A beta (35-25), produced a robust increase in intracellular calcium that remained after removal of extracellular calcium but was abolished by the phospholipase C inhibitor U-73122. There was no significant difference bt tween the calcium response to A beta (25-35) in platelets from patients with Alzheimer's disease and from age-matched controls. In contrast to the robust effects on calcium mobilisation in HEPES buffers, very little calcium response to A beta (25-35) was seen when Krebs (pH 7.8) buffer was used. (C) 2001 Elsevier Science Ltd. All rights reserved.