Recruitment of the intracellular Ca2+ by ultrashort electric stimuli: The impact of pulse duration

Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA. Electronic address: .
Cell calcium (Impact Factor: 4.21). 06/2013; 54(3). DOI: 10.1016/j.ceca.2013.05.008
Source: PubMed

ABSTRACT Nanosecond-duration electric stimuli are distinguished by the ability to permeabilize intracellular membranes and recruit Ca(2+) from intracellular stores. We quantified this effect in non-excitable cells (CHO) using ratiometric Ca(2+) imaging with Fura-2. In a Ca(2+)-free medium, 10-, 60-, and 300-ns stimuli evoked Ca(2+) transients by mobilization of Ca(2+) from the endoplasmic reticulum. With 2mM external Ca(2+), the transients included both extra- and intracellular components. The recruitment of intracellular Ca(2+) increased as the stimulus duration decreased. At the threshold of 200-300nM, the transients were amplified by calcium-induced calcium release. We conclude that nanosecond stimuli mimic Ca(2+) signaling while bypassing the usual receptor- and channels-mediated cascades. The recruitment of the intracellular Ca(2+) can be controlled by the duration of the stimulus.

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