Intracellular Inositol(1,4,5)-Trisphosphate Receptor Levels Are Preserved in Alzheimer’s Disease Platelets

An increasing number of signal transduction disturbances have been reported in Alzheimer’s disease. These changes are not restricted to histopathologically changed brain areas but are seen also in peripheral tissues. One of the most severe disturbances is a loss of calcium-mobilizing intracellular inositol(1,4,5)-trisphosphate receptors in Alzheimer cerebellar and cortical tissues. In the present study, the binding of [3H]inositol(1,4,5)trisphosphate ([3H]Ins(1,4,5)P3) to the calcium-mobilizing inositol(1,4,5)trisphosphate receptors in platelet membranes from eight Alzheimer’s disease patients and eight control subjects were investigated to determine its possible role as a biological marker in Alzheimer’s disease. It was found that there were no significant difference in [3H]Ins(1,4,5)P3 binding with respect to the number of sites measured at different protein concentrations or to the sensitivity of the binding to inhibition by nonradioactive Ins(1,4,5)P3 between Alzheimer disease platelets and controls. It is concluded that inositol(1,4,5)trisphosphate receptor levels are preserved in platelets from patients with Alzheimer’s disease.