title: Recruitment of the intracellular Ca2+ by ultrashort electric stimuli: the impact of pulse duration.
abstract: Nanosecond-duration electric stimuli are distinguished by the ability to permeabilize intracellular membranes and recruit Ca2+ from intracellular stores. We quantified this effect in non-excitable cells (CHO) using ratiometric Ca2+ imaging with Fura-2. In a Ca(2+)-free medium, 10-, 60-, and 300-ns stimuli evoked Ca2+ transients by mobilization of Ca2+ from the endoplasmic reticulum. With 2 mM external Ca2+, the transients included both extra- and intracellular components. The recruitment of intracellular Ca2+ increased as the stimulus duration decreased. At the threshold of 200-300 nM, the transients were amplified by calcium-induced calcium release. We conclude that nanosecond stimuli mimic Ca2+ signaling while bypassing the usual receptor- and channels-mediated cascades. The recruitment of the intracellular Ca2+ can be controlled by the duration of the stimulus.
authors.affiliation: Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA. iurii.semenov@gmail.com
authors.forename: Iurii
authors.initials: I
authors.lastname: Semenov
authors.forename: Shu
authors.initials: S
authors.lastname: Xiao
authors.forename: Olga N
authors.initials: ON
authors.lastname: Pakhomova
authors.forename: Andrei G
authors.initials: AG
authors.lastname: Pakhomov
mesh_terms: D000818:Animals; D016466:CHO Cells; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism; D020013:Calcium Signaling; D002463:Cell Membrane Permeability / Q000502:physiology; D006224:Cricetinae; D003412:Cricetulus; D004558:Electric Stimulation; D004721:Endoplasmic Reticulum / Q000378:metabolism; D016257:Fura-2 / Q000737:chemistry; D007425:Intracellular Membranes / Q000378:metabolism*; D018613:Microscopy, Confocal; D013997:Time Factors
chemical_list: D015220:Calcium Channels; D002118:Calcium; D016257:Fura-2
keywords: Calcium signaling; Electric field; Electropermeabilization; Electroporation; Nanosecond pulses