Large supraphysiologic transmembrane electrical potentials are
known to alter the molecular organization of the bilayer lipid
component of cell membranes, leading to ionic permeabilization
or "electroporation". Typically, membrane electroporation is
followed by several orders of magnitude increases in electrical
conductance and diffusive permeability to low-molecular-weight
solutes. Electroporation may be transient or stable depending
on whether the membrane eventually seals or remains permeabilized.
Factors that control sealing have not been well characterized.
This paper describes the kinetics of membrane sealing following
electroporation by pulses over a range of supraphysiologic potentials.
The increase in membrane conductance is highly nonlinear during
a -440-mV, 4-ms pulse and reaches two orders of magnitude greater
than baseline. Electroporation and relaxation sealing kinetics
are quite different, reflecting a significant hysteresis effect.
Thus, it appears that the magnitude and duration of the field
pulse are important factors in sealing.
