Ohnishi N, Fujiwara Y, Kamezaki T, Katsuki S. Variations of Intracellular Ca
2+ Mobilization Initiated by Nanosecond and Microsecond Electrical Pulses in HeLa Cells.
IEEE Trans Biomed Eng 2018;
66:2259-2268. [PMID:
30561339 DOI:
10.1109/tbme.2018.2886602]
[Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
GOAL
Herein, the variations in transient Ca2+ mobilizations in HeLa cells exposed to a single, non-thermal pulsed electric field (PEF) are described.
METHODS
Three PEF waveforms categorized by pulse duration and intensity were used to deduce the kinetics involved in Ca2+ mobilization. A fast microscopic fluorescent imaging system and a fluorescent molecular probe were used to observe transient intracellular Ca2+ mobilization after pulse exposure. The sources and pathways in the transient Ca2+ mobilizations were investigated using an inhibitor of inositol-1,4,5-trisphosphate receptor (IP3R) on the endoplasmic reticulum (ER) along with a Ca2+-free buffer.
RESULTS
When exposed to the 10-μs-long PEF, the Ca2+ concentration increased mainly at the cathodic region near the membrane. However, Ca2+ concentration increased at both anodic and cathodic regions when Na+ concentration in the buffer was reduced. Ca2+ concentration increased only in the presence of extracellular Ca2+.
CONCLUSION
These results suggest that the 10-μs PEF takes a large amount of extracellular Na+ into the cell through the electropermeabilized plasma membrane, especially at the anodic side, resulting in the suppression of the Ca2+ influx. On the contrary, the 20-ns-long PEF increased Ca2+ concentration in the surrounding region of the nucleus only in the presence of extracellular Ca2+. The PEF exposure with inhibition of the IP3R indicates that increased Ca2+ ions are released from the ER via the activated IP3R.
SIGNIFICANCE
These mechanisms could induce specific cell responses, such as Ca2+ oscillations, Ca2+ waves, and Ca2+ puffs.
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