Calcium bursts induced by nanosecond electric pulses.
We report here real-time imaging of calcium bursts in human lymphocytes exposed to nanosecond, megavolt-per-meter pulsed electric fields. Ultra-short (less than 30 ns), high-field (greater than 1 MV/m), electric pulses induce increases in cytosolic calcium concentration and translocation of phosphatidylserine (PS) to the outer layer of the plasma membrane in Jurkat T lymphoblasts. Pulse-induced calcium bursts occur within milliseconds and PS externalization within minutes. Caspase activation and other indicators of apoptosis follow these initial symptoms of nanosecond pulse exposure. Pulse-induced PS translocation is observed even in the presence of caspase inhibitors. Ultra-short, high-field, electroperturbative pulse effects differ substantially from those associated with electroporation, where pulses of a few tens of kilovolts-per-meter lasting a few tens of microseconds open pores in the cytoplasmic membrane. Nanosecond pulsed electric fields, because their duration is less than the plasma membrane charging time, develop voltages across intracellular structures without porating the cell.
Vernier
P Thomas
PT
Department of Electrical Engineering-Electrophysics, School of Engineering, University of Southern California, Los Angeles, CA 90089-0271, USA. vernier@mosis.org
Sun
Yinghua
Y
Marcu
Laura
L
Salemi
Sarah
S
Craft
Cheryl M
CM
Gundersen
Martin A
MA
D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002462:Cell Membrane / Q000737:chemistry; D018274:Electroporation; D006801:Humans; D017136:Ion Transport / Q000187:drug effects; D007476:Ionophores / Q000494:pharmacology; D019169:Jurkat Cells; D007700:Kinetics; D010507:Periodicity; D010718:Phosphatidylserines / Q000032:analysis; D012964:Sodium / Q000378:metabolism; D013997:Time Factors
D002121:Calcium Channel Blockers; D007476:Ionophores; D010718:Phosphatidylserines; D012964:Sodium; D002118:Calcium