INTRACELLULAR INOSITOL(1,4,5)-TRISPHOSPHATE RECEPTOR LEVELS ARE PRESERVED IN ALZHEIMERS-DISEASE PLATELETS

An increasing number of signal transduction disturbances have been rep orted in Alzheimer's disease. These changes are not restricted to hist opathologically changed brain areas but are seen also in peripheral ti ssues. One of the most severe disturbances is a loss of calcium-mobili zing intracellular inositol(1,4,5)trisphosphate receptors in Alzheimer cerebellar and cortical tissues. In the present study, the binding of [H-3]inositol(1,4,5)trisphosphate ([H-3]Ins(1,4,5)P-3) to the calcium -mobilizing inositol(1,4,5)trisphosphate receptors in platelet membran es from eight Alzheimer's disease patients and eight control subjects were investigated to determine its possible role as a biological marke r in Alzheimer's disease. It was found that there were no significant difference in [H-3]Ins(1,4,5)P-3 binding with respect to the number of sites measured at different protein concentrations or to the sensitiv ity of the binding to inhibition by nonradioactive Ins(1,4,5)P-3 betwe en Alzheimer disease platelets and controls. It is concluded that inos itol(1,4,5)trisphosphate receptor levels are preserved in platelets fr om patients with Alzheimer's disease. (C) 1997 Elsevier Science Inc.