DEVELOPMENT OF RESTING MEMBRANE-POTENTIALS IN DIFFERENTIATING MURINE NEUROBLASTOMA-CELLS (N1E-115) EVALUATED BY FLOW-CYTOMETRY

With the aid of a voltage-sensitive oxonol dye, flow cytometry was use d to measure relative changes in resting membrane potential (V-m) and forward angle light scatter (FALS) profiles of a differentiating/diffe rentiated murine neuroblastoma cell line (N1E-115). Electrophysiologic al differentiation was characterized by V, establishment. The (V-m)-ti me profile was found to be seed cell concentration-dependent for cell densities of less than 2 x 10(4) cells/cm(2). At higher initial cell d ensities, under differentiating culture conditions, V, development com menced on day 2 and reached a steady- state on day 12. The relative di stribution of differentiated cells between low and high FALS has been proposed as a potential culture electrophysiological differentiation s tate index. These experiments offer a general methodology to character ize cultured excitable cells of nervous system origin, with respect to electrophysiological differentiation. This information is valuable in studies employing neuroblastoma cells as in vitro screening models fo r safety/hazard evaluation and/or risk assessment of therapeutical and industrial chemicals under development.