Distinct pH homeostatic features in lymphoblasts from Alzheimer's disease patients.

Epstein-Barr-transformed lymphocytes from Alzheimer's disease patients showed the following distinct features in controlling the intracellular pH compared with cells from normal age-matched controls: (1) The alphaIgM-induced intracellular acidification was more pronounced in Alzheimer's disease than control cells and this effect appears to be associated with a loss of effectiveness of a Ca2+/calmodulin-dependent mechanism in controlling the activity of the Na+/H+ exchanger; and (2) the intracellular H+-buffering capacity and the rate of proton efflux in response to an acid load were both decreased in Alzheimer's disease cells. It is concluded that the amplitude of the intracellular pH changes under acid-loading conditions will always be greater in Alzheimer's disease than in control cells.