Models of electric field interactions with biological cells predict that pulses with durations shorter than the charging time of the outer membrane can penetrate and affect intracellular structures. Several other methods have been used to calculate the transmembrane potential with varying degrees of sophistication. Data on the dielectric constants and conductivities of cell membranes and cytoplasm, as well as other organelles, required for theoretical analyses have been obtained using dielectric spectroscopy of cells. Traditionally, the neglect of the intracellular regions for potential bioelectric phenomena can be attributed to the notion that intracellular organelles are generally shielded from external electric fields by the outer membranes. The Smoluchowski equation has been applied for the voltage-dependent description of the nonlinear membrane resistance and pore development. Physically, the radial displacement of the pore walls is facilitated by the electric field–driven Maxwell stress tensor created at the membrane–electrolyte interface.