Dual-fluorescence flow cytometric analysis of membrane potential and cytoplasmic free Ca2+ concentration in embryonic rat hippocampal cells

We have demonstrated simultaneous measurement of the membrane potential and cytoplasmic free Ca2+ concentration (Ca2+]i) by utilizing a dual-laser flow cytometer in embryonic rat hippocampal cell suspensions. Veratrine, a Na+ channel activator, induced both membrane depolarization and elevation of Ca2+]i. These actions of veratrine were all reversed by the presence of tetrodotoxin (TTX). These findings suggest that Na+ channels are functionally expressed in the cells and the activation of Na+ channels increases Ca2+]i. The usefulness of the flow cytometric analysis in elucidating the expression of membrane functions in the embryonic central nervous systems (CNS) is discussed.