Nanosecond pulsed electric fields applied to biological cells are now well recognized to induce a series of intracellular responses. These evidences have paved the route toward the use of electro-manipulation techniques to noninvasively altering the biochemical state of many intracellular functions. Although of the vast experimental progress, the more fundamental understanding of these electrostatic effects is quite controversial. Recently, several models which are based on the core-shell representation have been proposed in order to clarify these effects. However, since most sub-cellular organelles generally "exhibit" much complex and convoluted morphology, these models might be quite restricted in predicting the more native intracellular responses. Given these realizations, this study aims to theoretically explore the nature of induced cellular potentials in a more realistic model. For this purpose, a 3D cytoplasmic-embedded mitochondrion model has been constructed in order to imitate the morphological structure of a native cellular system. Based on finite numerical simulations, the electrically induced transmembrane potential gradients have been computed and examined against the responses obtained based on the approximated shell models. The prominent deviations obtained between the realistic and the approximated models arouse serious thoughts regarding the compatibility of these models to the analysis of sub-cellular organelles. (c) 2009 Elsevier B.V. All rights reserved.